1. Walk-In
Take out notebook, folder, pencil box. Copy this week’s AGENDA. Write name on paper, tape to candy donations, and put into period basket.

2. Background Review
1. What is digestion? 2. Does the digestive system consist of many pieces? Explain.

3. Lab Overview
In this lab, we will model the movement of food through the digestive system, by moving a tennis ball through a piece of plastic tubing, to . The tube will be marked with digestive organs and their distances from one organ to the next organ.

4. How does food move through the digestive system?
Experiment Question
How does food move through the digestive system?

5. Hypothesis
If food is swallowed, then it moves through the digestive system because _______________

6. Materials Lab sheet Tennis Ball Meter Stick Long Plastic Tube
Masking Tape
*The plastic tube represents the digestive system

7. Lab Sheet Please do not write on your lab sheet.
Read the procedure with your group.
When you measure to mark where an organ goes, do you go from the last organ or from the beginning of the tube?

8. Procedure – How to Mark the Tubing
Place a small piece of tape at the distance you measure. Mark on the tape the name of the organ and the distance FROM THE LAST ORGAN.

9. Procedure continued
3. Everyone – Take turns measuring organ lengths and labeling. Use the chart on your lab sheet to measure.
Everyone – Take turns moving the ball through the “digestive system”.
Discuss the organs the “food” is moving past, and what is happening at each.

10. Procedure Person B – Get the plastic tube and tennis ball.
Person C – Get the meter stick, tape and marker.

11. Organ Lengths Organ Length: cm Mouth 11
Esophagus (use mouth as starting point) 25
Stomach 22
Small Intestine
690
Large Intestine
152
Rectum 14

12. Clean -Up Person D – Remove the tape pieces and throw away.
Everyone – Help fold (not roll!) the tube neatly.
Person A – Return the tennis ball and tube.
Person D – Return the marker, meter stick and tape.
Everyone – Answer the five questions on your sheet.

13. Walk-In Take out notebook, folder, pencil box.
Answer these questions about yesterday’s lab:
How does food move through the digestive system?
What did the squeezing of your hands represent?
What do you think the digestive system is made of if it can squeeze like that?

14. Peristalsis
Peristalsis is the squeezing of muscles of the esophagus to move food down to the stomach.
It would move food toward the stomach even if you were standing on your head!

15. Sphincters
Sphincters are rings of muscles that act like valves, to let food go forward but not backward.

16. Muscles Squeeze
Food moves through the digestive system by CONTRACTIONS (squeezing) of muscles.