1. Lab Report- Mechanical and Chemical Digestion

2. Background Information
What is mechanical digestion?
Mechanical digestion is movement that breaks food down into smaller pieces.
Example: teeth crushing food in the mouth.
What is chemical digestion?
Chemical digestion is when chemicals are added to change food into different substances.
Example: Amylase in saliva changes bread into starch and sugar.

3. Purpose-
How does mechanical digestion affect the rate of chemical digestion?

4. Prediction
If we allow one antacid to remain whole, and crush the others into pieces, then
because

5. Plan- Materials 3 antacid tablets 30 ml of acetic acid (vinegar)
1 25 ml graduated cylinder
plastic stirring rod
plastic cup
1 pair of scissors/plastic knife
device for a timer

6. Plan- Procedure
1. ONE partner will take graduated cylinder to the vinegar station. Pour 10 ml of vinegar into the graduated cylinder.
2. Once you are sure your measurements are correct, carefully walk the graduated cylinder back to your seat and pour the 10 ml of vinegar into your plastic cup.
3. Start your timer.
4. Place 1 antacid tablet into the beaker with the vinegar.
5. Record observations every 30 seconds for a total of 3 minutes.

7. Plan- Procedure
7. Repeat steps 1-6 using an antacid tablet that you very carefully cut into 4 pieces. (Very carefully!)
8. Repeat steps 1-6 using an antacid tablet that you crush inside the snack baggie. Take care to keep the bag intact!

8. Data Collection Tablet Number Consistency Time (sec) Observations -
What is happening to the tablet?
Estimate the percent of the tablet that remains 1
Whole 30 60 90
120
150
180 2
4 pieces

9. Data Collection Tablet Number Consistency Time (sec) Observations
(What is happening to the tablet?)
Estimate the percent of the tablet that remains 3
Crushed 30 60 90
120
150
180

10. Conclusions
Do you see any patterns or trends in your data? If so, what are they?
Create a line graph for each estimated percent point. (There will be 3 lines in all)

11. Claims and Evidence
What is the answer to your prediction question? How does mechanical digestion affect the rate of chemical digestion?
What data do you have that supports your answer? Give specific examples.

12. Reflection What did you learn from this lab?
Discuss any errors or potential errors.
If you were asked to do this lab again, what would you do differently?

13. WRAP-UP All solid waste should be thrown into the trash can
All liquid waste should be washed down the sink while running water
Wipe work area down with a damp paper towel. I should not see any crumbs or trash on tables
Place safety glasses, scissors, etc. and items for next class at the station