Whether you want to make a stethoscope as part of a set of Healthy Heart activities or simply because your child is curious about how the one at the doctor’s office works, it’s a simple activity that requires just a few household materials. With it, you can help your child hear the difference between his resting and active heart rates as well as the difference between the sound of his heart rate and that of other people in your house.
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- a flexible tube (a Slinky pop toob toy is a great one, but a paper towel tube or a foot-long piece of dryer vent tubing will work, too)
- small funnel
- duct tape
- a medium-size balloon
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Ask your child the following questions to help her formulate a hypothesis about why a stethoscope might work better than listening with a naked ear to the heartbeat:
How does a doctor hear your heartbeat?
Why do you think a stethoscope works?
How do you think we’ll be using these materials to make your own stethoscope?
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Make the Stethoscope
- Put the small end of the funnel in one end of the pop toob, paper towel tube or dryer vent tubing. Push the funnel as far you can into the tube to insure a snug fit.
- Tape the funnel into place using duct tape. (we used bright green duct tape for our stethoscope, but any color works just as well.)
- Inflate the balloon to stretch it out. Let the air out and then cut the neck off of the balloon.
- Stretch the remaining part of the balloon tightly over the open end of the funnel, duct taping it into... place. This creates a tympanic membrane for your stethoscope. Now it's ready to use.
- Place the funnel end of the stethoscope on your child’s heart and the end of the tube to his ear.
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Questions to Ask
Why did we put the balloon on the funnel?
What do you hear with your stethoscope?
How fast is your heart beating?
Jog around the house or run in place for a few minutes and listen again. Do you hear a difference?
Does your heart beat faster or slower than an adult’s heart Why?
Is there a difference in your heartbeat versus that of another child close to your age?Continue to 5 of 5 below.
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What’s Going On
The homemade stethoscope helps your child hear his heart better because the tube and funnel amplify and focus sound waves. Adding a tympanic membrane also helps to amplify the vibrations of the sound waves.
Extend the Learning
- If you used a pop toob or dryer venting, let your child experiment with creating different shapes with the tube. Is there one way that helps conduct sound better?
- Listen carefully: Do you hear one sound or two sounds in your heartbeat? You should hear two: a long, lower sound... and a short, higher sound. The sounds are made by different sets of valves letting blood in and out of your heart.