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Digest This! (redirected from Digest-This)

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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) Below, create a Double Bubble thinking map 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







                                         mechanical                                                                                                chemical

                                          digestion                                                                                                  digestion












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?  What chemical changes (changes in taste) did you notice about the crackers?  How would you describe the taste as you chewed the crackers?  Record your observations below:





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 250 mL beaker half full of water.  Set the beaker aside.

C. Keeping your mouth closed, you may suck on 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 from start to finish. 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…) 

D. When finished, record both your stopping and total times.


3) Data Table 1


Start Time

Stop Time

Total Time

Sucker dissolving in mouth




Sucker dissolving in water





4)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 100 mL graduated cylinder.  rs.

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!


5) Data Table 2



Observation No Muscular Action

(BAG 1)

Observation With Muscular Action  (BAG 2)


(Steps 1-5)





Trial 1

(After 5




Trial 2

(After 10




Trial 3

(After 15





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 250 mL beakers, and a 100 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) in Data Table 3.


9) Data Table 3


Beginning amount of water

Remaining water in cup

1 paper towel




3 paper towels





10) Which paper towel had the largest surface area?



11) Which cup had the least amount of water remaining?  Why?



12) How is this like how villi in our small intestine help our small intestine absorb more nutrients?



Activity #6:  How Long is the Digestive System?

You will measure, using a meter stick, and construct a representation of the length of your digestive tracts using yarn, scissors, and tape.

A. Take a piece of yarn (red), measure, and cut from the back of your ears to the front of your lips to get the length of your mouth.

2. Take a piece of yarn (orange), measure, and cut from the bottom of your chin to bottom of your sternum to get the lengths of their esophagus.

3. Take a piece of yarn (yellow), measure, and cut from your thumb to your pinkie to get the length of your stomach.

4. Take a piece of yarn (green), measure, and cut from your heads to your feet and multiply that by four to get the length of your small intestines.

5. Take a piece of yarn (blue), measure, and cut from your heads to your feet once to get the length of your large intestines.

6. Connect the pieces of yarn using tape, and measure the total length of the yarn to get the approximate total lengths of your digestive tract.

7. Record the different digestive tract lengths in the class in Data Table 4.  Record your group’s average on the Smart Board and in Data Table 5.  Create a Bar Graph to compare the average digestive tract lengths of lab group to lab group.  Don’t forget to label your x-axis and y-axis!


13) Data Table 4


Measurement (inches)




















14) Data Table 5

Lab Groups

Average Measurement (inches)























15) Bar Graph






Check out this animation of the digestive system!



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