Every time the valves in your heart open and close to let blood flow through, it makes a 'dub-dub' sound. If you’ve ever wondered what your heart sounds like you can listen to your own heartbeat with a stethoscope made from rubber tubing, 2 funnels and a balloon. The typical stethoscopes that you see doctors using have a flat, round chest piece which is covered by a thin, tightly stretched piece of plastic called a diaphragm. When pressed against the chest it vibrates when a sound occurs and travels up the hollow tubing to the earpieces.
This stethoscope works on the same basis. The balloon stretched over the funnel becomes the diaphragm picking up the sounds and the smaller tunnel acting as the earpiece.
You will need:
1 large funnel
1 small funnel
1 balloon
Length of rubber tubing - you’ll need to make sure that your tubing can either fit inside or over the funnel spouts
Duct tape.
1 small funnel
1 balloon
Length of rubber tubing - you’ll need to make sure that your tubing can either fit inside or over the funnel spouts
Duct tape.
Method
Insert the funnels either into each end of the rubber tubing and seal with your duct tape.
Blow the balloon up to stretch it out and then let the air out. Cut the end off the balloon and stretch it over the large funnel securing with your tape. Make sure your balloon is stretched as tight as possible and completely airtight so the vibrations from your heartbeat can travel through the tubing! Just a note here - we actually used a pair of rubber gloves and it worked, but the thinner balloon will pick up the vibrations of the heartbeat better. The stethoscope also has a better chance of working if you use the smaller funnel as the listening end and place the large funnel with the balloon in the centre of your chest, just over the heart.
If you’re struggling to hear your heartbeat, try moving the stethoscope slightly to the left and make sure the room is very quiet. You can also try running around or do some star jumps to get your heart going and listening to the increased heart rate!
