“The Siphon-Pump Heart Model” Lesson 14: 14.1 “The Siphon-Pump Heart Model”

QUESTION: How does the human heart work?

HYPOTHESIS: I believe…because…

PROCEDURE: p. 123-124

Explore how the pump works: Use one pump and one cup of water to test the pump. See picture on p. 122 Be sure that the ends of both tubes remain in or pointed toward the water in the cup.

DATA: 1. What makes the water begin to flow through the pump? 2. Through which tube, the stiff one or the flexible one, does water enter the pump?

3. What keeps the water from flowing back through the tube when you release the bulb?

4. Listen closely as you squeeze the bulb 4. Listen closely as you squeeze the bulb. Can you hear any clicking sounds? If so, what seems to be causing them?

Work with your group to create a “closed” circulatory system: Use both pumps and both containers of water. Connect the parts so the water flows continuously through the model. You cannot add water to the cups. About the same amount of water must remain in each cup at all times.

To Complete Student Sheet 14.1c: Copy the names of the heart structures in the appropriate blanks using the picture displayed on the screen.

Compare Figure A & Figure B on student sheet 14.1b: The upside-down siphon pump system models the human circulatory system. As you refer to the two figures, complete the following activities:

Using student sheet 14.1c as a guide, label the human heart diagram on student sheet 14.1b. Also label the parts of the siphon-pump model as they represent the structures of the human heart.

Color-code the following on both illustrations on 14.1b: Left atrium—blue Left ventricle—red Right atrium—brown Right ventricle—black Human body—yellow Valves—green Aorta—orange Lungs—purple

Also on Sheet 14.1b: Study the arrows on Figure B that show the path of water through the model. Draw similar arrows on Figure A to show the direction of blood through the human heart.

Student Sheet 14.1a: Draw arrows to show the path that blood takes as it circulates through the human body.

DATA (cont.): 1. When you are operating your model heart, you should be able to hear the familiar “lub-dub” sound as well as see what causes it. Explain what causes the sound.

2. Why is the heart considered a double pump? 3. What is the function of the valves in the heart? 4. What do we mean when we say humans have a “closed” circulatory system?

VOCABULARY: Double pump Atria Ventricles Recirculate Closed system

CONCLUSION: Be sure to use complete sentences. Be sure to look back at your original question. Be sure to use your vocabulary words.