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TE Activity: Do You Have the Strength?

In this activity, students squeeze a tennis ball to demonstrate the strength of the human heart. Working in teams, they think of ways to keep the heart beating if the natural mechanism were to fail. The goal of this activity is to get students to understand the strength and resilience of the heart.

Engineers design instruments to help (or replace) the heart when something goes wrong. For example, they have designed tiny stents (a wire mesh tube used to prop open an artery during an angioplasty) to place in clogged arteries, they have developed a mechanical heart, and they have designed replacements for veins and heart valves. Engineers also develop surgical equipment and medical equipment to locate and monitor heart rates. Aerospace engineers are working to combat the loss of heart muscle in space. These engineers are trying to counter the microgravity affects by developing exercise equipment (treadmills, bicycles, etc.) for astronauts to keep their hearts healthy while traveling in space (astronauts usually work out at least two hours a day).

Learning Objectives
Materials
Introduction/Motivation
Procedure
Attachments
Troubleshooting Tips
Assessment
Extensions
Activity Scaling

Grade Level: 4 (3-5)	Group Size: 2
Time Required: 25 minutes	Activity Dependency : None
Expendable Cost Per Group : US$ .50
Keywords: heart, heartbeat, cardiac muscle, artificial heart, strength, pump

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Colorado Math
- 1. construct, read, and interpret displays of data including tables, charts, pictographs, and bar graphs; (Grades 0 - 4) [2005]
- 2. describe patterns and other relationships using tables, graphs, and open sentences; (Grades 0 - 4) [2005]
- 3. use numbers to count, to measure, to label, and to indicate location; (Grades 0 - 4) [2005]
- 5. select and use appropriate standard and non-standard units of measurement in problem-solving situations. (Grades 0 - 4) [2005]
Colorado Science
- Standard 1: Students understand the processes of scientific investigation and design, conduct, communicate about, and evaluate such investigations. (Grades 0 - 12) [1995]
- Standard 5: Students know and understand interrelationships among science, technology, and human activity and how they can affect the world. (Grades 0 - 12) [1995]
- Standard 6: Students understand that science involves a particular way of knowing and understand common connections among scientific disciplines. (Grades 0 - 12) [1995]
- 3.3 Students know and understand how the human body functions, factors that influence its structures and functions, and how these structures and functions compare with those of other organisms. (Grades 0 - 12) [1995]

The heart is a special muscle that never gets tired. The heart is able to alter the flow of blood through the body depending on the body's requirements. Have you ever noticed that your heart beats harder when you are exercising, stressed or frightened? Even at times when you heart has to work harder, it has to produce a force strong enough so that blood can reach all the parts of your body. Blood carries oxygen, and even the tips of your fingers and toes need oxygen to work properly.

The heart works like a pump: it pushes blood around your body through your blood vessels. The harder you are working (i.e., exercising), the faster your heart pumps blood through your body. Have you used a pump to get air into a bicycle tire or a basketball? How about pumping water from a well with a hand pump? Either way, you can become tired from pumping too long. The heart has to stay strong and healthy so that it can keep efficiently pumping throughout your entire life. Pumps can break down with use, and the heart can become clogged or break down just like any other pump. Sometimes, the heart can become clogged with fat when we eat too many fatty foods. If the heart stops pumping, our body is in big trouble!

Engineers design instruments to help (or replace) the heart when something goes wrong. For example, they have designed tiny devices to place in a clogged artery to allow blood to flow. Also, they have developed a purely mechanical heart for someone whose heart is no longer working properly, and they have even designed replacements for veins and heart valves. Engineers also develop surgical equipment to assist doctors and help patients survive during surgery.

How strong do you think your heart is? Well, today we are going to do a short activity that will help us discover how strong the heart muscle really is. Then we will take that new knowledge and think like engineers who design devices to help the heart pump work properly.

Before the Activity

Gather all necessary supplies.
Print out the Tennis Ball Squeeze Worksheet for each student.

With the Students

Ask students how strong they think their heart is. Record responses on the board. Let's see if we can be as strong as our heart.
Divide students into groups of two.
Pass out materials to each group.
Tell one student to hold the tennis ball in their strongest hand (generally, their writing hand).
Squeeze the ball as hard as possible; then, release the grip without dropping the ball.
Tell students that this is very similar to the force of one pump of the heart, but the difference is that the heart does not get tired.
Now, have the student squeeze the tennis ball as fast and as hard as they can for ten seconds, 30 seconds, and one minute. Their partner should count the number of squeezes, and record the results on the Tennis Ball Squeeze Worksheet.
Switch ball squeezer and counter, and repeat steps 4-7.
Share the group results with the entire class. Discuss with the students if it became harder to squeeze the tennis ball as time passed. Did anyone's hand hurt after squeezing for one minute? Imagine if you had to squeeze that tennis ball all day without stopping. You might get tired! That is how strong your heart is!
Engineers design devices to fix the heart when something has gone wrong. Ask the students to imagine that they must design a heart. Have them brainstorm ways to keep the heart pumping for ten years, plus have the strength to move blood through the body.

Pre-Activity Assessment

Discussion Questions: Solicit, integrate and summarize student responses.

How strong do you think your heart is? How hard does it need to pump to push blood throughout your body?

Activity Embedded Assessment

Worksheet: Have the students record measurements and follow along with the activity on their Tennis Ball Squeeze Worksheet. After students have finished their worksheet, have them compare answers with their peers.

Post-Activity Assessment

Engineering Poster: Using the knowledge they learned about the strength of the heart, have students create a poster of a design of a device to fix the heart when something has gone wrong. Have them title their posters with an engineering firm name that they make up (e.g., Shaky Heart Engineering Firm). Have the students work in teams of two to four if possible.

Integrated Teaching and Learning Program and Laboratory, University of Colorado at Boulder Jessica Todd, Julie Marquez, Sara Born, Denali Lander, Malinda Schaefer Zarske, Janet Yowell © 2004 by Regents of the University of Colorado
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0226322. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last Modified: August 30, 2006