THE HEART STOPPER

Overview:

 Students learn about the relationships between the heart and the blood vessels by using a simple pump system.

Objective:

 To create a model that simulates a heart attack by creating a blockage in the arteries that feeds into the heart.

Skills:

 Observation, collecting data, recording, inferring, drawing conclusions

Materials
Needed:
  • Spray cleaner pump bottle (pin-point nozzle removed) e.g., the type used for solutions that clean glass, appliances, etc.
  • Red food coloring added to water
  • 3 sections of clear plastic tubing: 1 of 61-cm length, and 2 of 30-cm ( available in the pet store)
  • 1 clear glass or plastic "T" junction for tubing
  • 2 measuring cups or beakers ( 1 marked "heart" and the other "body")
  • 4 different sized screws: 5mm,4mm,3mm,2mm ( any sizes will do as long as they vary in size)
  • 1 clothespin
  • 1 heavy twist-tie
  • 1 sheet of graph paper per pupil or group to record results
  • Paper towels or a cloth towel
  • Heart Stopper Student Worksheet

Preparation:
  1. Mix red food coloring with enough water to fill the spray bottle and the measuring cup or beaker you are using.
  2. Fill the spray bottle with the red-colored water. ( Note: The solution in the spray bottle provides stability for assembly)
  3. Attach the 62-cm tube to the bottle with the large twist-tie at one end and the "T" junction on the other end.

Lesson
Suggestions:

 Introduction:
In this exercise, you will work with a spray bottle to simulate the heart, clear plastic tubes to simulate arteries, and screws held in place with clothespins to simulate blockages.

As the blockage increases in size, the force needed to pump is increased,. simulating increased heart force. During this exercise you may rupture an artery, so it is necessary to have paper towels or a cloth towel nearby.

How do blood pressure and sensitivity of arteries relate? If a screw is "blown out" of the tube during the exercise, you have simulated a blood clot moving in the system. Explore the possibilities using the simple pump system provided for you.

Procedure:

 Students should work in groups of four. One student will pump; another changes screws; another measuring fluid, and the fourth student records the data and does the graph plotting. Student have the following directions on their worksheet, The Heart Stopper Data Table.
  1. Pump the bottle as many times as your heart beats in one minute in the inactive mode. This can be timed quickly, or return to the data in the lesson, Heart Throbs. Note any difficulty the pumper might have had.
  2. Collect the water in the beakers and measure it. Record the measurement.
  3. Insert the smallest (2mm) screw in the end of the short tube and secure it with a clothspin.
  4. Repeat steps one and two.
  5. Replace the screw, increase the size of the screw used, pump. measure the water output, and record the data until you have data for each sized screw.

Extra
Challenages:
  1. Have students increase heart rate, and then repeat the above process. With each blockage will the amout of fluid pumped to the heart decrease in the same proportions, as it did in the first expirment? Have students make inferences on what happens when the heart works twice as fast as usual.
  2. Change the name "heart muscle" on the measuring cup to "the brain." The concept of the stroke can then be displayed. A stroke is caused by a blood clot in an artery of the brain.
  3. Have students research the causes of arterial blockage and look for ways in which lifestyles influence such problems.
Go to: The Heart Stopper Student Worksheet

This lesson plan in an excerpt from RX for Science Literacy, a 300-page teacher manual published by the North Carolina Association for Biomedical Research (NCABR). The manual captures the complex research process in an easy-to-use format and is filled with background information, handouts, lesson plans and activities to assist teachers in the classroom. You can learn more about the manual and order it online from NCABR.


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