Section I — Coach Water — Water and Your Body
This section covers Chapter 2, Lessons 2.1 through 2.4.
Part A — Vocabulary (20 points, 2 points each)
Select the best answer for each question.
1. An ion is:
A) A type of cloud B) An atom or molecule that has gained or lost electrons and carries an electrical charge C) A bone D) A muscle
2. Sodium (Na⁺) is:
A) The main positive ion inside cells B) The main positive ion outside cells — workhorse of extracellular fluid balance C) A type of bone D) Always present in equal amounts inside and outside cells
3. Potassium (K⁺) is:
A) The main positive ion outside cells B) The main positive ion inside cells C) A vitamin D) A muscle
4. The sodium-potassium pump is:
A) A device used at the gym B) A protein in every cell membrane that uses energy to push Na⁺ out and pull K⁺ in — runs constantly C) A bone in the arm D) The same as a heart pump
5. A nephron is:
A) A type of food B) The tiny tube-shaped functional unit of the kidney — about 1 million in each kidney C) A type of bone D) A blood cell
6. The glomerulus is:
A) A type of bone B) A tight tuft of capillaries at the start of each nephron — where blood is filtered under pressure C) A muscle in the back D) The same as the bladder
7. ADH (antidiuretic hormone) is:
A) A signal for sleep B) A hormone released by the pituitary gland that tells the kidney to reabsorb more water C) A vitamin D) A type of muscle
8. Hyponatremia is:
A) High blood sodium B) Low blood sodium — most commonly caused (in healthy people) by drinking far more water than the kidney can excrete, especially without replacing sodium during long heavy exercise C) The same as dehydration D) A bone disease
9. Diuresis is:
A) A vitamin B) Increased urine output C) The same as constipation D) A type of skin condition
10. Cerebral edema is:
A) A normal feeling of dizziness B) Swelling of the brain — the most dangerous consequence of severe hyponatremia C) A muscle name D) A bone problem
Part B — Concept Comprehension (20 points, 2 points each)
Select the best answer for each question.
11. Your kidneys filter approximately how much fluid per day across all nephrons?
A) 1 liter B) 18 liters C) About 180 liters D) 1,000 liters
12. Of that filtered fluid, approximately what fraction is reabsorbed into the bloodstream?
A) About 1% B) About 25% C) About 50% D) About 99% (only ~1.5 L per day becomes urine)
13. The kidney decides how much water to keep mostly by responding to:
A) The temperature outside B) ADH released by the pituitary in response to changes in blood salt concentration detected by the hypothalamus C) What you ate last D) Your mood
14. Coffee in normal amounts (for habitual drinkers) is:
A) Always dehydrating B) About as hydrating as plain water — caffeine is a mild diuretic but the water in the cup outweighs it C) Required for life D) The same as alcohol
15. Milk is:
A) Slightly more hydrating than plain water because its small amounts of sodium, potassium, and protein slow water excretion B) Always dehydrating C) The same as cola D) A type of metal
16. During a long marathon in heat, drinking only plain water with no sodium replacement can lead to:
A) Improved hydration without limits B) Exercise-associated hyponatremia — blood sodium drops dangerously, can cause headache, confusion, seizures, brain swelling, and in severe cases death C) Faster running D) Better digestion
17. John Snow is famous for:
A) Inventing modern bottled water B) His 1854 Broad Street cholera map, which helped prove that contaminated water spread cholera and became foundational to public health C) Discovering the kidney D) Inventing the toilet
18. Alkaline water claims to "alkalinize the body" are:
A) Strongly supported by research B) Not supported by biology — stomach acid neutralizes the water immediately, and the body controls its own pH tightly through kidneys, lungs, and blood buffers C) Only true at high altitude D) Required by law
19. Around the world today, approximately how many people lack reliably clean drinking water?
A) Nobody — clean water is universal B) About 2 billion C) About 200 D) Less than 1,000
20. Coach Water's main message at Grade 7 is:
A) Drink as much water as possible B) The body's water and electrolyte balance is precisely managed; understanding the system shows why both dehydration and overhydration are problems, and why honest hydration practice respects the system C) Stop drinking water D) Bottled water is always safer
Part C — Application (30 points, 6 points each)
Write 2-4 complete sentences for each question.
21. Explain in your own words how the kidney manages body water. Use the words filtration, reabsorption, and ADH. Include the rough math (180 L → ~1.5 L).
22. Safety recognition. A friend is running their first long race in the heat and plans to "drink as much plain water as possible to stay safe." Using everything Lesson 2.3 taught about hyponatremia, explain why this plan can be dangerous and what the better approach is.
23. Compare milk and coffee to plain water as hydration sources. Why does milk hydrate slightly better than water, and why does coffee hydrate about the same as water for habitual drinkers?
24. A wellness influencer claims that drinking "alkaline water" will make your body alkaline and prevent disease. Using the science from Lesson 2.4 (stomach acid, body pH control), explain why this claim does not match biology.
25. Briefly describe how John Snow's Broad Street map (1854) helped establish modern public health. Why does Coach Water bring this up — what is the connection to your tap water today?
Continue to Section J — Synthesis Essay.