Download Activity #1: Mechanical vs. Chemical Digestion

NAME:____________________________
DATE:_____________
Digest This! - Digestive System Lab
Essential Question: What happens to the food you eat at lunch?
Activity #1: Mechanical vs. Chemical Digestion
Think about the differences we’ve learned between mechanical and chemical digestion, and what they do to
help our bodies break down the food we eat into nutrients our body can use.
1) Create a Venn diagram comparing and contrasting the two types of digestion: mechanical and chemical
Include:
 where each takes place
 which organs in the digestive tract carry out mechanical digestion
 which organs carry out chemical digestion
 which organs do both
Activity #2: Digestion in the Mouth, Part 1
A. Each person in the lab group needs two unsalted soda crackers from the teacher.
B. Chew the crackers for two minutes without swallowing.
2) What physical changes did you notice about the crackers?
3) What chemical changes (changes in taste) did you notice about the crackers?
4) How would you describe the taste as you chewed the crackers?
Activity #3: Digestion in the Mouth, Part 2
A. One person from the lab group should get two suckers from your teacher. Unwrap both suckers.
B. Put one sucker in your mouth. Place the extra sucker in a beaker full of water.
C. Keeping your mouth closed, you may suck but NOT chew the sucker. Without chewing, record
in Data Table 1 the time it takes for the sucker to completely dissolve in your mouth.
D. Record the time it took for the sucker to dissolve in water from start to finish. (You may need to go
on to the next activities while waiting…)
Data Table 1
Start Time
Stop Time
Total Time
Sucker dissolving in mouth
Sucker dissolving in water
5) Which sucker dissolved first? What caused that sucker to “disappear”?
Activity #4: Hands on Digestion (stomach)
A. Get 2 plastic sandwich bags and 2 crackers from the teacher. You also need a graduated cylinder
B. Place one cracker in each bag. Carefully pour 60 mL (1/4 cup) of vinegar into each sandwich bag.
C. Designate one bag to represent “No Muscular Action” (stomach 1) and the other bag to represent
“With Muscular Action” (stomach 2).
D. Taking note of the time, observe the contents of stomach 1. Record your initial observations under
“No Muscular Action” in Data Table 2. Place the bag off to the side and check/record observations
again in 5 minutes. Try not to move the bag too much as you make your observations.
E. Take stomach 2 and gently squeeze the bag 6 times being sure not to rip or accidently open it.
Record your initial observation under “With Muscular Action” in Data Table 2. Place the bag off to
the side. Each time you check the bag squeeze it 6 more times, then record your
observations. Record your observations every 5 minutes.
F. While waiting, go on to Activity #5, but watch your time carefully!
Data Table 2
Time
Observation No Muscular Action
Observation With Muscular Action
Initial
(Steps 1-5)
Trial 1
(After 5
minutes)
Trial 2
(After 10
minutes)
Trial 3
(After 15
minutes)
6) Why did we add vinegar to the bags?
7) What differences did you see between the two bags?
8) Which “stomach” did a better job “digesting” the crackers? Why?
Activity #5: How do Villi aid the Small Intestine in Absorption?
A. Get 4 paper towels per group, two beakers, and a graduated cylinder.
B. Using the graduated cylinder, pour 100 mL of water into each beaker.
C. In the first beaker, dip one folded paper towel. In the second beaker, dip 3 folded paper towels.
D. Wait 30 seconds, and record the volume of water left in the cup (using a graduated cylinder).
Data Table 3
Beginning amount of water
1 paper towel
3 paper towels
Remaining water in cup
9) Which paper towel had the largest surface area?
10) Which cup had the least amount of water remaining? Why?
11) How is this like how villi in our small intestine help our small intestine absorb more nutrients?
Activity #6: Digestive System Model
At this point, you should have your digestive system model colored, pieced together, and
honored with a creative name. Once all of this is complete make sure you add the following to
your model:
1) Labels/Key- All of the digestive system organs present in the model should be
labeled (arrows or color key) and a short description of the function provided (i.e.
Esophagus moves food by peristalsis)
2) Type of Digestion- Along with each description should include whether this section
of the digestive system uses mechanical, chemical, or both types of digestion. (Be
sure to explain what this means, i.e. mouth completes mechanical digestion by using
the teeth and chemical digestion by using the saliva)
3) Enzymes- For the digestive organs that complete chemical digestion be sure to list
any enzymes that are present.