1. The Stomach Lab What liquids does the stomach need for digestion?

2. Test Tube A: Day 1 10 ml of pepsin

3. Test Tube B: Day 1 10 ml Hydrochloric Acid

4. Test Tube C : Day 1 5 ml of Pepsin 5 ml of Hydrochloric Acid

5. Test Tube D : Day 1 Dilute Pepsin 5 ml Pepsin 5 ml Water

6. Test Tube E : Day 1 Dilute acid 5 ml acid 5 ml water

7. Test Tube F : Day 1 10 ml water Think about why we have the test tube with water.

8. Test Tube A – 10 ml Pepsin Day 1 Day 2 - 3

9. Test Tube B – 10 ml Acid Day 1 Day 2 - 3

10. Test Tube C – 5 ml of Pepsin and 5 ml of Acid Day 1 Day 2 - 3

11. Test Tube D – Dilute Pepsin Day 1 Day 2 - 3

12. Test Tube E – Dilute Acid Day 1 Day 2 - 3

13. Test Tube F – 10 ml Water Day 1 Day 2 - 3

14. Post Lab Questions 1) Which liquids were the best at digesting the egg white? 2) What did this lab demonstrate about the ability of HCl (acid) alone to digest food? How do you know? 3) What did this lab demonstrate about the ability of pepsin alone to digest food? How do you know? 4) Which do you think plays a greater role in digestion, pepsin, HCl (acid), or the pepsin and HCl (acid) together? Explain why. 5) How did test tubes A,B, and C help you draw conclusion about food digestion in this investigation? In other words, what does this say about what the stomach needs to digest food? 6) Why was it necessary to have all 6 test tubes? Explain. What does the test tube with water show us?