Chapter 1: Light and Your Body

Chapter Introduction

The sun is rising somewhere right now. Somewhere on Earth, the sky is turning from blue-black to dark gray to pale orange to bright gold. Birds are starting to sing. The world is waking up.

Hi. I am the Rooster.

I teach about light. I am the bird who wakes up before the sun. Every morning, I sit on a fence and watch the sky get lighter. I crow when the first ray of sun appears. I do not need a clock. I am a clock. Roosters have been doing this for thousands of years, ever since people first started keeping chickens. The sun comes up. The Rooster crows. The day begins.

That is what this chapter is about. Light. The sun. The day-night cycle that your body has been built to follow.

This is the first time you and I are talking about light together. I am cheerful. I am attentive. I am alert without being anxious. I love mornings — but I also love sunsets, and even quiet dark nights. Light has many sides. We will look at them together.

In this chapter, you will learn three big ideas.

The first big idea is that your body has a clock that follows the sun. Morning light tells your body "it's day, time to be awake." Evening dark tells your body "it's night, time to slow down." This has been true for as long as people have been people.

The second big idea is how light helps you. Morning sunlight helps you wake up, feel alert, and sleep better at night. The Cat (Coach Sleep) and I work very closely on this — the Cat handles the night side of the cycle, I handle the day side. We are partners.

The third big idea is the most important one. Light needs care. Looking at the sun can hurt your eyes — never do it. Bright screens at night can make sleep hard. Some kids feel sad in dark winters. The Bear, the Turtle, the Cat, the Lion, the Penguin, the Camel, the Dolphin, and I all agree on the rules for taking care of yourself.

Are you ready? Look toward your nearest window for a moment. Notice the light. The Rooster is calm. The Rooster is ready. Begin.

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Lesson 1.1: Light and Your Body's Day

Learning Objectives

By the end of this lesson, you will be able to:

• Tell that your body has a clock that follows the sun
• Notice that morning light feels different from evening light
• Name three kinds of light (sunlight, indoor light, screen light)
• Understand that kids in different places have different amounts of light
• Notice how morning light makes you feel compared to evening light

Key Terms

The Rooster Crows

The Rooster has been watching the sky for a long, long time. I will tell you what I have seen.

The sun rises in the morning. The sun sets in the evening. The world is bright during the day. The world is dark during the night. Every day, every night, all your life. This has been happening since long before you were born, since long before your great-great-grandparents were born, since long before the first people walked on the Earth.

Your body knows this rhythm. Inside your body, deep inside your brain, there is a small clock that has been counting time since you were a baby. Your body's clock follows the sun [1, 2]. Morning comes — your body says "wake up, get going." Evening comes — your body says "slow down, get ready to sleep." Night comes — your body says "sleep now, repair, dream."

You do not have to think about any of this. Your body does it on its own. It is one of the smartest things your body does.

The Rooster knows this rhythm because the Rooster is built around it. So are you. So is almost every animal on Earth.

What Light Does for Your Body

Light does many things. Some of them you can see. Some of them you cannot see at all — but your body still notices.

Here is the most important thing the Rooster wants you to know at your age. Light tells your body what time of day it is.

When light enters your eyes — even when you are not looking right at it — special parts in your eyes notice. They send a signal to the small clock in your brain. The clock reads the light and figures out: morning? afternoon? evening? night? Then the clock helps the rest of your body get ready for what comes next [1, 3].

Morning light says: Time to wake up. Be alert. Get going.

Evening dim light says: Time to wind down. Get ready to rest.

Nighttime darkness says: Time to sleep deeply. Let the body fix itself.

Your body listens to these signals all day, every day. Most kids never know it is happening. The Rooster wants you to know.

Three Kinds of Light

Not all light is the same. The Rooster wants you to know about three big kinds of light.

1. Sunlight. This is light that comes from the sun itself. Sunlight is the strongest light on Earth. Even on a cloudy day, sunlight outside is much brighter than the lights inside your house. The body's clock pays more attention to sunlight than to any other kind of light [4].

2. Indoor light. This is the light from lamps, ceiling lights, kitchen lights, classroom lights. Indoor light is much dimmer than sunlight, even when it feels bright to your eyes. Your body's clock notices indoor light but does not get as strong a signal from it as from sunlight.

3. Screen light. This is the light from phones, tablets, TVs, computers — anything with a glowing screen. Screen light is bright and full of blue colors. It can be tricky. Even at night, when your body should be getting ready for sleep, a bright screen close to your face can tell your body's clock "wait, it might still be day." The Cat told you about this in Your Sleep and You. The Rooster agrees.

The Rooster is not saying screens are bad. Screens are part of life. The Rooster is just saying: screens are a special kind of light, and your body's clock notices them.

Kids in Different Places Have Different Light

The Rooster wants you to know something important.

Kids live in many different places on Earth. Some places have very different amounts of light.

• Kids near the equator (the middle line of the Earth) get about the same amount of daylight all year long. Sunrise and sunset happen at almost the same time every day.
• Kids in the far north or far south (like Alaska, parts of Canada, Norway, Sweden, the southern tip of South America) have very different summers and winters. In summer, the sun is up almost all day and night. In winter, the sun is up for only a few hours, or not at all.
• Kids in the middle (most of the United States, much of Europe, much of Asia, most of South America) have summer days with lots of daylight and winter days with less.

If you live somewhere with long dark winters, you may have noticed that mornings feel different in winter than in summer. That is normal. Bodies handle this — but bodies do better when grown-ups help with light during the dark months. The Rooster will say more in Lesson 2 and Lesson 3.

The Rooster is for every kid in every place. Long winter, long summer, in between — your body is doing the same job everywhere.

Some Bodies Notice Light Differently

The Rooster wants to say one more thing before this lesson ends.

Some kids have bodies that notice light differently than other kids' bodies.

• Some kids have low vision or are blind. Their eyes work differently. But here is something amazing — their bodies still know what time of day it is. The body has other ways to read the rhythm of day and night, not just through the eyes. The body clock still works.
• Some kids have light-sensitive bodies. Bright lights or certain kinds of light can give them headaches or even migraines. If you are one of these kids, you and your trusted grown-ups know what helps you.
• Some kids have eye conditions that need special care. Their eye doctor and trusted grown-ups help.
• Some kids wear glasses. Their eyes work great with the right help. The Rooster loves glasses — they are tools, like inhalers are tools (the Dolphin told you about inhalers).

All of these bodies are normal. The Rooster never compares one kid's eyes or light-sense to another's. Bodies are different. Light stories are different. Yours is yours.

Notice the Light Around You Right Now

Here is a small thing the Rooster loves doing.

Stop reading for a moment. Look around the room. Notice the light.

• Where is the brightest light coming from? A window? A lamp? A screen? An overhead light?
• Is the light warm (yellow-orange) or cool (white-blue)?
• Is the room mostly bright or mostly dim?
• Is it morning, afternoon, or evening where you are?
• How does the light feel? Energizing? Calming? Sleepy?

There are no right answers. The Rooster just wants you to notice.

Most kids never look at light this way. Once you start, you will see things you never saw before. The Rooster thinks that is one of the small gifts of this chapter.

Lesson Check

1. What does your body's clock follow?
2. What does morning light tell your body? What does evening dim light tell your body?
3. Name three kinds of light the Rooster talked about.
4. Do all kids get the same amount of daylight where they live? What does the Rooster say about that?
5. Look around the room you are in. Where is the brightest light coming from?

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Lesson 1.2: How Light Helps You

Learning Objectives

By the end of this lesson, you will be able to:

• Name three ways morning sunlight helps your body
• Tell why the Cat and the Rooster work together
• Understand why bright screens close to bedtime can make sleep harder
• Name four general practices that help most kids with light
• Notice your own morning and evening light

Key Terms

A Quick Rooster Story

The Rooster wakes early. Before the sun comes up, the Rooster is already on the fence, looking east. The first hint of light — a tiny lift of color in the sky — and the Rooster is awake.

Why? Because the morning is the most important part of the day for setting your body's clock. The first light of the day tells your body: the day is starting. Get ready.

The Cat lives the other end of this story. The Cat naps a lot — but the Cat is especially busy at night, when sleep is happening. The Cat takes over when the sun goes down.

The Rooster handles morning. The Cat handles night. We are partners in the day-night cycle. We agree on almost everything.

Morning Light Helps You

Here is something the Rooster wants every kid to know. Morning sunlight is one of the best things you can do for your body — for free.

When you get some sunlight in the morning, your body's clock gets a clear signal: yes, it is day, time to be awake. After that signal, three things happen:

1. You wake up better. Your body's clock helps you feel more alert, more energetic, more ready to do things [1, 3]. Some kids who get morning sunlight find that the foggy "just-woke-up" feeling lifts faster.

2. You sleep better that night. This is the magic part. Morning sunlight sets your body's clock so that when night comes, your body knows it is time to sleep. Kids who get some morning sunlight often fall asleep easier and sleep more deeply [5, 6]. The Cat agrees — morning sunlight is one of the things that makes the Cat's job easier.

3. You often feel a little happier. Bright light in the morning can lift mood. This is one reason mornings of bright weather feel different from mornings of dark, gloomy weather. Your body responds to the light.

The Rooster is not going to tell you exactly how long to be in the morning sun or exactly what time. Your trusted grown-ups know your family's schedule. Some kids look out a window for a few minutes. Some kids walk to school. Some kids play outside before school. Some kids open curtains. All of these are great. The body's clock is happy with any of them.

About Vitamin D

The Bear told you about vitamins in Food and Your Body. Vitamins are tiny parts of food that keep your body running well. The Bear mentioned vitamin D — the vitamin that helps your bones get strong.

The Rooster has a small addition to what the Bear said. Your body can also make vitamin D from sunlight on your skin.

When sunlight (only the kind from the sun, not from indoor lights or screens) touches your skin, your body uses some of it to make vitamin D. That vitamin D then helps your bones grow and stay strong. This is one more reason getting some sunlight matters — especially in the summer when sun is plentiful [7].

In winter, when sun is weaker and you cover up with clothes, your body makes less vitamin D from the sun. Many kids in cold or far-north places need vitamin D from food (eggs, fish, milk, some kinds of mushrooms) or from a vitamin pill in winter. Your trusted grown-ups and doctor know what is right for you.

The Bear and the Rooster agree on this: food and sunlight work together for your body.

Evening Light Helps You Wind Down

Now flip the story.

In the evening, as the sun goes down, the world gets dimmer. Your eyes notice. Your body's clock notices. Slowly, your body starts to make its own natural sleep helper — a small chemical that says time to wind down. Your eyes get heavier. Your thoughts slow down. Bedtime starts to feel like a good idea [8].

This is your body doing its job. The Cat already told you in Your Sleep and You that your body has a built-in slow-down for night. The Rooster adds: light is the main signal that starts that slow-down.

When the light is dim in the evening, your body knows. When the light is bright, your body can get confused.

Why Screens Before Bed Are Tricky

This is the part where the Cat and the Rooster team up.

Bright screens — phones, tablets, TVs, computers — give off bright blue-rich light. Bright blue light is the kind of light the sky has during the day. So when your eyes see a bright screen at night, your body's clock can get tricked. It thinks: wait, it might be day still. Then your body slows down its sleep-helper signal. You feel less sleepy, even when it is way past bedtime [9].

This is why so many grown-ups and so many kids have trouble going to sleep when they used a screen right before bed. The body's clock got the wrong signal.

The Rooster is not saying screens are bad. Screens are part of life. The Rooster is just saying: screens close to bedtime can make sleep harder. Your family decides what works for you. Some families have rules about screens and bedtime. Some families do not. The Cat and the Rooster both think turning screens off — and dimming other lights — about an hour before bedtime helps most kids sleep better. Your trusted grown-ups know what is right.

Four Things That Help Most Kids With Light

The Rooster is not going to tell you exactly what your day should look like. Your family knows your weather, your home, your school, your schedule.

What the Rooster can share is four general things that help most kids with light. These are general human practices, not rules-you-must-follow. People have been doing them — without thinking about it — for thousands of years.

1. Get some sunlight in the morning when you can. Open the curtains. Look outside. Eat breakfast near a window. Walk to school. Play outside before school. Any of these are great. Even five minutes of morning sunlight helps your body's clock more than an hour of indoor light. You do not need to stare into the sun (the Rooster will be firm about this in Lesson 3). You just need to be in a place where bright outdoor light reaches your eyes.

2. Spend time outside during the day. Recess. Walking. Playing. Helping in the yard. Going to the park. The more sunlight your body's clock gets during the day, the better it works.

3. Dim the lights as bedtime gets close. As evening comes, dimmer lights help your body get ready for sleep. Many families turn off bright overhead lights and use lamps instead. Some families dim their lamps. The Cat agrees: a dim home in the evening is a sleep-friendly home.

4. Limit screens close to bedtime. Screens are bright and tricky for the body's clock. Your trusted grown-ups make the rules about screens in your family. The Cat and the Rooster both think most kids sleep better when screens go off some time before bed.

These four are not magic. They are just things that help. If you do most of them already, great. If you do not, talk to a trusted grown-up about what fits your family.

Coaches Working Together

The Rooster works closely with the other coaches. We all teach different things, but we all agree about a lot.

• The Bear (Food) said real food and vitamins help your body. The Rooster adds: sunlight gives you vitamin D, and food gives you the rest. They work together.
• The Turtle (Brain) said your brain works better when your body is taken care of. The Rooster says: morning sunlight helps your brain feel awake and ready for the day.
• The Cat (Sleep) is my closest partner. The Cat handles the night side of the cycle. I handle the day side. We are a team. You will hear the Rooster and the Cat agree more than any other coach pair. Morning sunlight and good night sleep are two halves of the same thing.
• The Lion (Move) said your body is built to move. The Rooster says: moving outside in the morning gets you sunlight and movement at the same time. Two coaches, one walk.
• The Penguin (Cold) teaches cold weather. Cold places often have less winter light. The Penguin and I are good friends for kids in cold dark winters.
• The Camel (Hot) teaches heat and sun safety. The Rooster and the Camel agree on sun protection — sunscreen, hat, shade for strong sun.
• The Dolphin (Breath) teaches breath. A morning walk with slow breaths is a beautiful way to start the day. The Rooster and the Dolphin team up here too.

The Rooster loves being part of this team. So are you, your family, your friends, your teachers, and the trusted grown-ups in your life.

Notice Your Morning and Evening

Here is a small thing the Rooster wants you to try.

Tomorrow morning, when you first wake up, notice the light. Is it bright? Dim? Sunny? Cloudy? Indoor only? Mixed?

Tomorrow evening, before bed, notice the light again. Same questions.

The next day, notice once more. Same questions.

The Rooster is not asking you to write anything down (unless you want to — you will get to in the end-of-chapter activity). Just notice. Two minutes. Once in the morning, once at night. Maybe both you and a trusted grown-up can do this together.

Most kids never look at their morning light or evening light. Now you do. The Rooster thinks that is wonderful.

Lesson Check

1. Name two ways morning sunlight helps your body.
2. Why do the Cat and the Rooster work together so closely?
3. Why can bright screens close to bedtime make sleep harder?
4. Name three of the four general practices that help most kids with light.
5. The Bear said vitamin D helps your bones. Where can your body get vitamin D besides food?

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Lesson 1.3: Light Safety

Learning Objectives

By the end of this lesson, you will be able to:

• Know the most important rule about your eyes and the sun
• Tell what to do if there is a solar eclipse
• Name three things that protect your eyes from strong light
• Recognize seasonal feelings that some kids have in dark winters
• Know what to do if a feeling about light or season feels really big

Key Terms

The Rooster Is Honest

The Rooster is going to be honest with you. Light is mostly wonderful. Sunlight is one of the best things on Earth. Morning light helps you. Evening dim light helps you sleep. Your body's clock follows the light without you having to think about it.

But light can also hurt you if you do not take care. The Rooster wants you to know the rules. Not to scare you. To help you take care of yourself.

The most important thing in this whole chapter is this: light is mostly good, but you must take care of your eyes. The Rooster will say more.

The Most Important Rule: Never Look at the Sun

The Rooster needs to say this clearly because it is the most important light rule there is.

Never look directly at the sun. Not for a moment. Not on a dare. Not to test what happens. Not because the sun looks pretty. Not because it is low in the sky and seems softer.

Looking at the sun — even for a few seconds — can hurt the back of your eyes in a way that does not heal. This is a hurt that can last forever [10]. Your eyes do not feel pain when this happens, which is why some kids think the sun is safe to look at. It is not.

When the Rooster says never look at the sun, the Rooster means never. Even when the sun is rising or setting. Even when there is a haze or a cloud. Even when grown-ups are around. The rule does not change.

You can absolutely be outside in sunlight. You can play. You can walk. You can run. You can squint and notice the light. You can look at the brightness near the sun, like the sky around it. What you cannot do is look right at the sun itself.

If you want morning sunlight to help your body's clock, that is great. Stand outside. Look at the sky in general. Look at the trees, the buildings, the ground. The sunlight reaches your eyes from all directions. You do not have to look at the sun to get the benefit.

The Rooster is firm about this because the Rooster loves your eyes.

Special Rule: Solar Eclipses

Sometimes the moon passes in front of the sun. This is called a solar eclipse. It is rare. Most kids only see one or two in their whole childhood. When it happens, the sky goes dim in the middle of the day, and grown-ups get excited. People want to look up. People want to see.

Here is the rule: during a solar eclipse, you still cannot look at the sun without special glasses. Even when the moon is in front of the sun. Even during the dimmest part. Eclipses can hurt eyes badly, and many people have been hurt because they thought the eclipse made the sun safe to look at. It does not.

The only safe way to look at the sun during an eclipse is with special eclipse glasses — very dark, certified glasses made for eclipse viewing. Regular sunglasses do NOT work, no matter how dark they are. Looking through a regular camera, a phone, or a regular telescope without a special filter is also not safe.

If a solar eclipse happens where you live, your trusted grown-ups will help you decide how to enjoy it safely [11]. They might find eclipse glasses. They might watch the eclipse on a TV or computer instead. They might use a pinhole projector — a fun science trick where you can watch the shape of the eclipse on the ground without looking up.

The Rooster says this rule the same way the Penguin says the cold-water rule and the Camel says the hot-car rule. Some rules are non-negotiable. This is one of them.

Other Eye Safety Rules

A few smaller rules that matter:

• Never point lasers at your eyes or anyone else's eyes. Laser pointers, laser toys, laser pens — even tiny ones — can hurt eyes. Lasers in toys are usually pretty weak, but lasers in pointers and bigger gadgets can damage the back of the eye [12]. Treat them carefully.
• Wear sunglasses in very bright sun. Sunglasses block some of the strong light. They keep your eyes more comfortable. They also protect your eyes over many years. (The Camel said this about hot sunny days. The Rooster agrees for any very bright sun.)
• Wear safety goggles or glasses if a grown-up gives them to you. Some activities (chemistry, woodworking, certain games) can throw things at your eyes. Goggles protect.
• If you wear glasses, take care of them. Your eye doctor and trusted grown-ups have taught you. Keep them clean. Keep them safe.

The Rooster cares about your eyes a lot. You have only one pair. They have to last your whole life.

Screens at Night Make Sleep Hard

The Cat already taught you this in Your Sleep and You. The Dolphin and I both agree. Bright screens close to bedtime can make sleep harder.

If you are using a screen close to bedtime and your eyes are wide open at lights-out time, your body's clock may have gotten confused by the screen light. Your trusted grown-ups decide what works for your family. Some families have screen-time rules. Some families do not. Either way, the Rooster wants you to know why screen light at night is tricky — so you can notice it in your own body.

Some Kids Have Light-Sensitive Bodies

The Rooster also wants to talk about kids whose bodies notice light very strongly.

Some kids get headaches or migraines from bright lights. A migraine is a bad kind of headache that can come with feeling sick, seeing strange shapes, and being very bothered by light or sound. If you are one of these kids, you and your trusted grown-ups know what helps — quiet dark rooms, certain medicines, knowing what triggers your migraines.

Some kids have eye conditions that make their eyes more sensitive to light. They may wear special glasses, including tinted ones. Their eye doctor helps.

Some kids have autism or other sensory differences and find very bright lights, fluorescent lights, or certain flickering lights hard. That is real. Trusted grown-ups can help find better lights or quieter spaces.

If you are one of these kids, the Rooster sees you. Your body is just doing what your body does. There is no wrong way to have a body. The Rooster never makes anyone feel bad for needing different light than other kids.

Seasonal Feelings — When Winter Feels Heavy

Here is something the Rooster wants you to know that not many people talk to kids about.

In winter, when days are short and dark, some people feel different. They might feel sadder, more tired, less interested in things they usually love, or just kind of heavy. This happens to kids as well as grown-ups. It is called seasonal feelings, and it happens because there is less daylight for the body's clock to use [13, 14].

This is not a sign that something is wrong with the kid. It is the body responding to less light. In spring and summer, when days get longer, the feelings often lift on their own.

But while it is happening, kids and grown-ups can do things that help:

• Get more morning light when you can. Even on a cloudy winter day, outdoor light is much brighter than indoor light.
• Spend time outside during daylight hours. Bundle up. Go for walks. Play in the snow.
• Move your body (the Lion taught you this — moving helps feelings).
• Eat real food (the Bear taught you this — including foods with vitamin D in winter).
• Sleep well (the Cat taught you this).
• Tell a trusted grown-up if the heavy feelings are sticking around or getting bigger. (The Turtle taught you this most clearly in Your Brain and You.)

Seasonal feelings can be small (a few cloudy days feel a little blue) or bigger (a whole winter feels heavy). If your feelings are sticking around longer than a few days, or getting bigger, tell a trusted grown-up. Doctors and counselors can help. There are also special bright-light lamps that can help some people in winter — but those are used with a grown-up's guidance, not on your own.

When to Tell a Grown-Up Right Away

The Rooster has the same kind of list the other coaches have. Tell a trusted grown-up right away if:

• You looked at the sun or a laser and your eyes hurt or feel weird
• You have a sharp eye injury (something poked you, something splashed in your eye, you fell and hit your eye)
• A very bad headache is making it hard to see, or coming with feeling sick
• Your feelings have felt heavy or dark for many days during a dark season and they are not lifting
• Something just feels wrong with your eyes or your feelings

You do not need to be sure. You do not need to figure it out yourself. If something feels wrong, tell a grown-up. That is your part. The grown-up handles the rest.

For eye emergencies — when something has hurt your eye or your vision suddenly changes — the grown-up may take you to a doctor right away. If something is very serious, grown-ups can call 911. The Lion, the Penguin, the Camel, the Dolphin, and the Rooster all agree: kids tell grown-ups, grown-ups handle big calls.

When a Feeling Feels Really Scary or Unsafe

The Rooster is going to be careful and clear here, because this part matters most.

Sometimes a feeling can get really big. Maybe a heavy winter feeling sticks around for weeks. Maybe it gets darker than usual. Maybe a feeling makes you not want to be here. Maybe a feeling makes you want to hurt yourself.

If a feeling like that ever comes up — at any time, in any season — tell a trusted grown-up right away. Not later. Right then. The grown-up will not be mad. The grown-up will be glad you told them.

There are special phone numbers grown-ups can use when feelings get really scary or unsafe. The Rooster wants you to know these exist, so that if a feeling like this ever happens, you can tell a grown-up, and the grown-up can use one of these helpers. You do not have to remember the numbers. The grown-ups in your life can use them.

For an eye injury or any emergency — when someone is hurt or needs help right away:

• A grown-up can call 911. In the United States, 911 is the phone number for emergencies. Real people answer fast and send help. Kids your age do not call 911 on their own (unless a grown-up has taught you to and there is no grown-up around) — you tell a grown-up, and the grown-up makes the call.

Helpers grown-ups can call when feelings feel really scary or unsafe:

• The 988 Suicide and Crisis Lifeline: a grown-up can call or text 988, day or night. Real people answer. They help right away.
• Crisis Text Line: a grown-up can text the word HOME to 741741, day or night. Real people answer by text.

Helpers grown-ups can call about other big or hard worries:

• SAMHSA National Helpline: 1-800-662-4357, day or night. Real people answer.

These helpers are for grown-ups to use when you and they need them. Kids your age do not call helplines on their own. You tell a trusted grown-up first. The grown-up takes care of the rest.

The Bear, the Turtle, the Cat, the Lion, the Penguin, the Camel, the Dolphin, and I are all saying the same thing. We agree. You are part of a team. You are not alone.

Light Is the Body's Oldest Friend

The Rooster will end this lesson with one quiet thought.

Light is the body's oldest friend. The sun has been rising and setting for as long as Earth has existed. Animals have been waking with the sun and resting with the dark for hundreds of millions of years. Your body's clock is older than human history — older than your great-great-grandparents, older than all the languages, older than every story ever told.

You inherited that clock. It still works. Even if you live in a city with lots of indoor lights and screens, your body is still listening for the sun.

The Rooster's job is to help you notice. Open a curtain. Step outside. Look at the sky (not the sun!). Notice the morning. Notice the evening. Notice the difference. Once you start, you will see the day-night cycle everywhere — in how you feel, in how you sleep, in how your body wakes up and winds down.

The Rooster will see you again at higher grades. The Rooster will teach you more then. For now, this is enough.

The Rooster is calm. The Rooster is ready. The Rooster is in your corner.

Lesson Check

1. What is the most important rule about your eyes and the sun?
2. If a solar eclipse happens, can you look at it with regular sunglasses?
3. Name two things that protect your eyes from strong light.
4. What are seasonal feelings? What can help with them?
5. If a feeling about your eyes, your light, or your season ever feels really scary or unsafe, what is the first thing the Rooster says you should do?

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End-of-Chapter Activity: A Day of Light

The Rooster has one activity for you. It is gentle. It takes one day of noticing, with a trusted grown-up's help at the end. You can do this any day.

What You Need

• A piece of paper or a small notebook
• A pencil or crayons
• One day of your normal life
• A trusted grown-up to share with

What You Do

Step 1 — Make a light sheet. At the top of your paper, write the date. Below the date, make four boxes: Morning, Midday, Evening, Bedtime. Leave room under each one.

Step 2 — Notice four times across the day. Four times during one normal day, pause and notice the light around you. For each time, write down or draw:

• What kind of light is around me? (sunlight, indoor light, screen light, mix?)
• Is it bright or dim?
• How does it feel? How do I feel right now?

Examples:

• Morning, 7:30 a.m.: Mostly indoor light, a little sunlight through the kitchen window. Bright but soft. Feel a little sleepy still, a little hungry.
• Midday, 12:30 p.m.: Lots of sunlight outside at recess. Very bright. Feel energetic and warm.
• Evening, 6:00 p.m.: Indoor lights on, sky outside getting orange-pink. Feel calm and a little tired.
• Bedtime, 8:30 p.m.: Lamp light only, very dim. Feel sleepy.

Step 3 — Pick your favorite light moment. At the bottom of your sheet, write: My favorite light today was ______. Which moment did you enjoy the most? Why?

Step 4 — Notice screens. In a corner of your sheet, write down about how much time you used a screen today. (Best guess is fine.) Did you use a screen right before bedtime? How did sleep feel afterward?

Step 5 — Share with a trusted grown-up. Show your light sheet to a trusted grown-up. Ask them: Do you notice the light during your day? What is your favorite light? Listen to their answer. Most grown-ups have never thought about it. You will hear something new.

Step 6 — Keep the sheet. Save your light sheet somewhere safe. The Rooster thinks light sheets are interesting to look back at later.

What You Will Get From This

You will start to see the rhythm of light in your day — something most kids never notice. You will find a favorite light moment that is yours. You will share a small new noticing with a trusted grown-up.

That is a tiny habit. It is also a big skill. The Rooster thinks both are true.

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Vocabulary Review

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Chapter Review

These questions are not a test. They are a way to check what you remember. Take your time. Look back at the lessons if you need to. There are no tricks.

1. What does your body's clock follow?

2. Name two ways morning sunlight helps your body.

3. Why can bright screens close to bedtime make sleep harder?

4. What is the most important rule about your eyes and the sun?

5. During a solar eclipse, what kind of glasses are safe? What kind are NOT safe?

6. If a feeling about light or season ever feels really big or hard, what is the first thing the Rooster says you should do?

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Instructor's Guide

This guide is for parents, caregivers, teachers, and other grown-ups using this chapter with a child in Grade 3 (ages 8-9).

What This Chapter Teaches

This is the first chapter the child will read about light in the CryoCove Library. It is the foundation. The chapter teaches three big ideas at age-appropriate depth:

1. Light and your body's day. Your body has a built-in clock that follows the sun. Morning light says "be awake"; evening dim light says "wind down"; night dark says "sleep." Three kinds of light are introduced: sunlight (strongest), indoor light (much dimmer than it feels), and screen light (bright and tricky for the body's clock). The chapter explicitly includes kids in different latitudes (long winter darkness, equatorial year-round light, everywhere in between), kids who are blind or have low vision (their bodies still respond to light cycles through other channels), and kids with light-sensitive bodies (migraine, autism with sensory differences, certain eye conditions). Inclusion is load-bearing.

2. How light helps you. Morning sunlight helps wake up alert, sleep better that night, and feel a little happier. The Bear's vitamin D thread is picked up: skin makes vitamin D from sunlight. The Cat (Sleep) and Rooster (Light) day/night partnership is explicit and celebrated. Four general practices are introduced as research-informed things-that-help: get some morning sunlight when you can, spend time outside during the day, dim the lights as bedtime gets close, limit screens close to bedtime. None of these are prescriptive protocols (no lux measurements, no "X minutes within Y hours after waking" framing) — they are general human practices people have followed for thousands of years.

3. Light safety. This is the safety-critical lesson, paralleling the prior G3 Lesson 3 structures. The chapter's most distinctive load-bearing safety message is the eye-safety rule: never look directly at the sun, ever. Solar retinopathy is permanent and quick. The chapter teaches this clearly, includes the special-case solar eclipse rule (only certified eclipse glasses are safe; regular sunglasses are NOT), and adds laser safety, sunglasses recommendations, and general eye-care framing. Screens-and-sleep carries forward from the Cat chapter with the Rooster adding the why. Seasonal feelings are introduced at preventive depth — some kids feel sadder/more tired in dark winters; trusted-grown-up framing reinforces the Turtle's mental-health framework. Migraines, vision differences, sensory differences are all named and normalized. The two-tier protective framing matches prior G3 chapters: everyday light worry → trusted grown-up; emergency (eye injury, severe headache from light, sustained heavy winter feelings) → 911 via a grown-up.

What This Chapter Does NOT Teach

This chapter is intentionally light on certain content that becomes appropriate at later grades — and rigorously avoids one content area entirely:

• NO LIGHT-EXPOSURE PROTOCOLS. No prescriptive "morning sunlight protocols" (no lux measurements, no "within the first hour after waking" framing, no specific durations, no branded routines). The Rooster at G3 teaches the general rhythm of day and night, period. The most-named popular morning-sunlight protocol in current culture is associated with one of the five K-12-firewall-excluded wellness figures; the chapter teaches the underlying biology (which is real and research-informed) without ever naming the figure or the branded protocol.
• No circadian biology vocabulary beyond simplest. SCN, melatonin technical pharmacology, photoreceptors, ipRGCs, chronotype, zeitgeber, lux scale — none of these are named at G3. Grade 6 introduces the basics (wavelength, eye anatomy, lux).
• No light-therapy device prescriptions. Bright-light therapy lamps for SAD are mentioned briefly in the seasonal-feelings section as something used with a doctor's guidance, never as a kid-managed protocol.
• No vitamin D dosing. The chapter mentions that some kids in dark winter climates may need vitamin D from food or a pill, with the trusted grown-up and doctor handling specifics.
• No detailed eye-anatomy or vision-science vocabulary. Grade 6 introduces rods, cones, ipRGCs.

If your child asks questions in these areas, the best answer is: "That is a great question. Let's figure it out together." Then you, the trusted grown-up, decide what to share.

How to Support the Child

A few things you can do that align with the chapter's framing:

• Make morning sunlight easy. Open curtains at breakfast. Eat near a window. Walk to school when you can. None of this needs to be a "protocol" — the chapter explicitly avoids that framing. Just morning light, in whatever amount your family's life allows.
• Reinforce the never-look-at-the-sun rule. This is a one-conversation rule that protects your child for life. Solar retinopathy is permanent and quick. Make it concrete: never stare at the sun, ever, even briefly, even at sunset.
• Plan for solar eclipses. When an eclipse is coming to your area, plan ahead for certified eclipse glasses (ISO 12312-2 standard) or pinhole-projector viewing. If safe viewing is not possible for your family, watching on TV or computer is also fine. The thrill of an eclipse is real; eye injury is not worth the risk.
• Be matter-of-fact about screens at bedtime. Most evidence-informed family practice involves dimming bright screens for some time before bed. Your family's specific rules are yours to set; awareness of the why supports thoughtful decisions.
• Notice seasonal mood shifts. Some kids do feel heavier in dark winters. Light, movement, and ordinary trusted-grown-up support help most of them. If you live in a far-north climate, this is worth knowing.
• For kids with vision differences, migraines, or sensory differences: the chapter is for them too. Hold their experience as normal and supported.
• Be the one your child can come to about a light worry. The chapter explicitly tells the child to talk to a trusted grown-up. Make sure they know you are that grown-up.

Watching for Warning Signs

Children ages 8-9 are not too young to develop concerning patterns around light, vision, or seasonal mood. The chapter is preventive, not reactive. But if you notice any of the following, please contact your pediatrician or a qualified clinician:

• A child reporting sudden eye pain, blurred vision, or seeing spots after looking at the sun or any bright light — seek eye care urgently.
• A child with sustained heavy feelings during a dark season (lasting more than two to three weeks, with sleep changes, appetite changes, withdrawal) — seasonal affective patterns in children warrant clinical attention.
• A child with frequent migraines or worsening photosensitivity — pediatric neurology / ophthalmology referral may be appropriate.
• A child with unusual eye-rubbing, squinting, or vision changes — eye doctor evaluation.
• Any mention of not wanting to be here, wanting to hurt themselves, or feeling hopeless — these require immediate response, regardless of season.

Verified resources (May 2026):

• 988 Suicide and Crisis Lifeline: call or text 988, 24/7.
• 911: for any acute medical or safety emergency, including eye injuries with vision changes and severe sudden headaches.
• Crisis Text Line: text HOME to 741741, 24/7.
• SAMHSA National Helpline: 1-800-662-4357, 24/7.
• Your pediatrician is the best starting place for any non-emergency light, vision, or seasonal mood concern. For eye-specific concerns, a pediatric ophthalmologist or your child's optometrist.

Note: the NEDA helpline (1-800-931-2237) is not functional as of this writing. Use the National Alliance for Eating Disorders number (866-662-1235) instead if relevant.

Pacing

If you are using this chapter in a classroom:

If you are using this chapter at home, two lessons per week is comfortable. Lesson 3 is the longest and most safety-critical; budget extra time, and the never-look-at-the-sun rule and the eclipse rule are worth reinforcing every year, especially before any known upcoming eclipse.

Lesson Check Answers

Lesson 1.1:

1. The sun. (Your body's clock follows the rising and setting of the sun.) 2. Morning light says "be awake, get going." Evening dim light says "wind down, get ready for sleep." 3. Sunlight, indoor light, and screen light. 4. No. Kids near the equator have similar daylight all year. Kids in the far north or south have very long summer days and very short winter days. Kids in the middle have summer and winter differences. 5. The child's own observation. Any honest answer is correct.

Lesson 1.2:

1. Any two of: helps you wake up alert, helps you sleep better that night, often makes you feel a little happier, helps your body make vitamin D. 2. Because the Rooster handles the day side of the day-night cycle and the Cat handles the night side — they are partners. Morning sunlight and good night sleep are two halves of the same thing. 3. Because bright blue-rich screen light is the kind of light the sky has during the day, so screens at night can trick the body's clock into thinking it is still daytime. 4. Any three of: get some morning sunlight when you can, spend time outside during the day, dim the lights as bedtime gets close, limit screens close to bedtime. 5. From sunlight on the skin. (The Bear added that vitamin D also comes from food.)

Lesson 1.3:

1. Never look directly at the sun. (Not for a moment. Not on a dare. Not ever.) 2. No. Regular sunglasses do NOT protect your eyes during an eclipse. Only certified eclipse glasses are safe. (You can also use a pinhole projector or watch on TV.) 3. Any two of: never look at the sun, wear sunglasses in bright sun, wear a sun hat, never point lasers at eyes, wear safety goggles when grown-ups give them, take care of glasses. 4. Feelings that come and go with the seasons — some people feel sadder or more tired in dark winters. Things that help: more morning light, time outside, moving, real food, sleep, and telling a trusted grown-up if heavy feelings stick around. 5. Tell a trusted grown-up right away. The grown-up can call a crisis line or 911 if needed.

Chapter Review Answers

1. The sun (and the natural day-night cycle). 2. Any two of: wake up alert, sleep better that night, feel happier, help body make vitamin D. 3. Bright blue-rich screen light tricks the body's clock into thinking it is still day, so the body slows down its sleep-helper signal. 4. Never look directly at the sun, ever. 5. Certified eclipse glasses are safe. Regular sunglasses are NOT safe, no matter how dark. 6. Tell a trusted grown-up right away. The grown-up can call a doctor, a crisis line, or 911 if needed.

Discussion Prompts

Open-ended questions to ask the child after the chapter:

1. What is one thing you noticed about light today that you had not noticed before?
2. Do you usually get morning sunlight before school? What could make it easier to get some?
3. What is your favorite kind of light — morning, midday, evening, indoor, screen, candle? Why?
4. The Rooster and the Cat are day/night partners. What does that mean to you?
5. If a younger sibling tried to look at the sun, what would you say to them?
6. Have you ever noticed feeling different in winter than in summer? What is it like for you?
7. What is one of the four general light practices you would like to try this week?
8. The Rooster says light is the body's oldest friend. What do you think that means?

Common Child Questions

• "Can I look at the sun if it's setting? It looks so pretty." No. Even at sunset, the sun is bright enough to hurt the back of your eyes. Look at the colors in the sky around the sun. Look at the clouds. Look at the trees. But not at the sun itself.
• "What if I looked at the sun for a second already?" Tell a trusted grown-up. Most kids who briefly glance at the sun are fine. But if your eyes hurt, your vision is blurry, or you see spots that do not go away, an eye doctor should check.
• "Why does morning light wake me up?" Light enters your eyes and tells the small clock in your brain "it is morning." The clock then tells the rest of your body to wake up and get ready for the day. This has been happening to humans for thousands of years.
• "Are screens really that bad at night?" Not bad — tricky. Screen light is bright blue light, the kind your body's clock reads as "day." Using a screen close to bedtime can confuse the clock and make falling asleep harder. Your family decides what works for you.
• "Why am I more tired in winter?" Less daylight, especially less morning sunlight, can make your body's clock work differently. Many people feel a little more tired or low in dark months. It is normal. Things help — outside time, morning light, movement, real food, sleep, and trusted grown-ups.
• "What is special about eclipses?" During a solar eclipse, the moon goes in front of the sun and the sky gets dark in the middle of the day. It looks safe to look up because it is dimmer. But the sun is still strong. Looking at it without certified eclipse glasses can hurt your eyes badly.
• "Why do I get headaches from bright lights?" Some kids' bodies are very sensitive to light, especially certain kinds (fluorescent lights, flashing lights, very bright sun). This is normal. Your doctor and trusted grown-ups can help you figure out what helps.
• "Can I get sunburn from indoor light?" Almost never. Sunburn happens from a specific kind of light (ultraviolet, or UV) that comes from the sun. Most indoor lights do not have much UV. Tanning beds do, which is why doctors say tanning beds are not safe for kids.
• "I'm blind. Does my body still have a clock?" Yes. Your body has other ways to follow the day-night rhythm besides through the eyes. The clock still works. Your trusted grown-ups know your body well.

Parent Communication Template

Dear families,

Your child is beginning the first chapter of the CryoCove Library Coach Light curriculum — Light and Your Body. This is a Grade 3 chapter at the very start of a long curriculum that will continue through high school and beyond.

What the chapter covers:

• That your body has a built-in clock that follows the sun's day-night cycle
• Three kinds of light (sunlight, indoor light, screen light) and how each affects the body's clock
• That kids in different climates and with different bodies (blind/low vision, light-sensitive, migraine-prone, autism with sensory differences) all have their own light story
• How morning sunlight helps wake-up, sleep, mood, and vitamin D
• The Cat/Rooster day-night partnership
• Four general practices that help most kids with light (morning sunlight when you can, outside time, dim evening lights, screen limits close to bedtime)
• Eye safety — most importantly, never look directly at the sun, including during solar eclipses (only certified eclipse glasses are safe)
• Seasonal feelings in dark winters and when to tell a grown-up

Tone: The chapter is cheerful, attentive, morning-energetic, and inclusive. The Rooster never compares one child's eyes or light-sense to another. Light is framed for the rhythms of a normal day and night — never as a prescriptive protocol with specific durations, intensities, or branded routines.

What this chapter does not teach: any branded morning-sunlight protocols, prescriptive lux measurements or durations, detailed circadian biology vocabulary, light-therapy device dosing, vitamin D specific amounts, or detailed eye anatomy. These arrive at later grades.

End-of-chapter activity: Your child will spend one day noticing the light around them four times (morning, midday, evening, bedtime), pick a favorite light moment, notice their screen time, and share with a trusted grown-up (you, if available). Please support this — it invites the child into a noticing habit most adults have never developed.

A note on Lesson 3: Lesson 3 covers light safety. The chapter's most important safety rule is never look directly at the sun, ever, even briefly, even at sunset. The solar-eclipse special case (only certified eclipse glasses are safe; regular sunglasses are NOT) is taught explicitly. Laser-pointer eye-injury risk and screen-and-sleep are also covered. Seasonal feelings are introduced gently at preventive depth — some kids feel heavier in dark winters, and trusted-grown-up framing is reinforced. 911 framing for emergencies is used at age-appropriate depth, parallel to the prior G3 chapters.

Warning signs we ask families to notice: Beyond the acute eye-injury and sustained-seasonal-mood signs the chapter teaches, please watch for any child showing unusual sun-staring behavior (often a TikTok-style dare or curiosity), worsening photosensitivity or migraines, or any mention of not wanting to be here. The chapter does not introduce or normalize any light-exposure practice that could be replicated unsafely.

If you have any questions, please reach out to your child's teacher or to us at the CryoCove team.

Warmly, The CryoCove Curriculum Team

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Illustration Briefs

Lesson 1.1 — The Sun's Day Placement: After "The Rooster Crows." Scene: A wide gentle scene showing the sun's journey across the sky in three panels reading left-to-right. Panel 1: dawn — pink-and-gold sky over a peaceful house and yard, a Rooster perched on a fence facing the rising sun, no shadows yet. Panel 2: midday — bright clear sky, the sun overhead, a child playing outside with a small dog. Panel 3: evening — golden-orange sunset over the same house, a child sitting on the porch with a cup of something warm, lights starting to come on in the house windows. A long curving arrow connects the three panels, showing the sun's path across the sky. Mood: peaceful, daily, the rhythm of a normal day. Show diverse skin tones and family settings across the chapter's illustrations. Critically: never show anyone looking at the sun directly. Aspect ratio: 16:9 web, 4:3 print.

Lesson 1.2 — Four General Light Practices Placement: After "Four Things That Help Most Kids With Light." Scene: A simple four-panel illustration showing the four practices. Panel 1: a child in pajamas looking out a sunny morning window, smiling, with a bowl of cereal on the table. Label: "Get some morning sunlight." Panel 2: a child playing outside under blue sky with a friend, a Rooster watching nearby. Label: "Spend time outside during the day." Panel 3: a softly lit living room in the evening — a parent reading with a child under one warm lamp, no overhead lights, no screens visible. Label: "Dim the lights as bedtime gets close." Panel 4: a kitchen with a phone and tablet sitting in a small basket on a shelf, a child reading a paper book in a comfy chair. Label: "Limit screens close to bedtime." Coach Light (the Rooster) stands warmly to one side of the four panels with wings slightly raised in a friendly way. Show diverse skin tones across the kids. Mood: warm, practical, cheerful, never product-marketing. Aspect ratio: 16:9 web, 4:3 print.

Lesson 1.3 — Eyes for the World, Not for the Sun Placement: After "Other Eye Safety Rules." Scene: A simple, calm scene that does NOT scare the reader. Show a child outside on a sunny day wearing regular sunglasses and a sun hat, looking at the world around them — NOT at the sun. A trusted grown-up is nearby, also wearing sunglasses, pointing at something interesting in the trees. Above the scene, a small clear text box reads: "Eyes are for seeing the world — not for staring at the sun." Coach Light (the Rooster) stands nearby with one wing gently raised, looking pleased. Show diverse skin tones. Mood: bright, safe, warm, never scary. The illustration teaches the right thing — looking at the world around — not the wrong thing. Critically: never depict anyone looking at the sun, even with sunglasses on. Aspect ratio: 16:9 web, 4:3 print.

Optional — Lesson 1.3: Seasonal Feelings Placement: After "Seasonal Feelings — When Winter Feels Heavy." Scene: A simple, warm illustration showing a child in winter clothes (coat, hat, mittens) outside on a snowy day, looking up at a softly cloudy winter sky with a thin band of pale sun light through the clouds. The child has a thoughtful expression — a little quiet, but okay. A trusted grown-up walks beside them, holding a steaming mug, smiling gently. Snow on the ground, a few trees, a soft pale daylight. Coach Light (the Rooster) stands at the edge of the scene, watching kindly. A small label reads: "Some kids feel heavier in dark winters. That is okay — there are things that help, and trusted grown-ups are part of them." Mood: gentle, real, never sad-stereotype, never bleak. The illustration normalizes seasonal feelings without dwelling. Show diverse skin tones. Aspect ratio: 16:9 web, 4:3 print.

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Citations

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2. Foster, R. G., & Kreitzman, L. (2017). Circadian Rhythms: A Very Short Introduction. Oxford University Press.

3. Lockley, S. W., & Foster, R. G. (2012). Sleep: A Very Short Introduction. Oxford University Press.

4. Hattar, S., Liao, H.-W., Takao, M., Berson, D. M., & Yau, K.-W. (2002). Melanopsin-containing retinal ganglion cells: architecture, projections, and intrinsic photosensitivity. Science, 295(5557), 1065-1070.

5. Wright, K. P. Jr., McHill, A. W., Birks, B. R., Griffin, B. R., Rusterholz, T., & Chinoy, E. D. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology, 23(16), 1554-1558.

6. Tarokh, L., Saletin, J. M., & Carskadon, M. A. (2016). Sleep in adolescence: physiology, cognition and mental health. Neuroscience and Biobehavioral Reviews, 70, 182-188.

7. Holick, M. F. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281.

8. Lewy, A. J., Wehr, T. A., Goodwin, F. K., Newsome, D. A., & Markey, S. P. (1980). Light suppresses melatonin secretion in humans. Science, 210(4475), 1267-1269.

9. Hale, L., & Guan, S. (2015). Screen time and sleep among school-aged children and adolescents: a systematic literature review. Sleep Medicine Reviews, 21, 50-58.

10. Yannuzzi, L. A., Fisher, Y. L., Krueger, A., & Slakter, J. (1987). Solar retinopathy: a photobiologic and geophysical analysis. Transactions of the American Ophthalmological Society, 85, 120-158.

11. Chou, R., Dines, J. P., Maples, J. L., Mosley, J. F., Aldoroty, R. A., & Beverstock, G. C. (2017). Eye safety during solar eclipses. American Academy of Ophthalmology Clinical Statement. aao.org.

12. Birtel, J., Harmening, W. M., Krohne, T. U., Holz, F. G., Issa, P. C., & Herrmann, P. (2017). Retinal injury following laser pointer exposure. Deutsches Ärzteblatt International, 114(49), 831-837.

13. Swedo, S. E., Pleeter, J. D., Richter, D. M., Hoffman, C. L., Allen, A. J., Hamburger, S. D., Turner, E. H., Yamada, E. M., & Rosenthal, N. E. (1995). Rates of seasonal affective disorder in children and adolescents. American Journal of Psychiatry, 152(7), 1016-1019.

14. American Academy of Pediatrics, Council on Communications and Media. (2016). Media and young minds. Pediatrics, 138(5), e20162591.