Steps to make a model of …

Aim:

To make a homemade Stethoscope.

Apparatus Required

• A tubing piece
• Scissors
• A balloon
• A timer
• Rubber band

Procedure

• Take a tubing and fit a funnel at both the ends.
• Enlarge the balloon by blowing and then let the air out.
• Cut top third of the balloon.
• Stretch the top of the balloon tightly above the open end of any one of the funnels. You can use a band to hold it in the correct place.

• Sit in a quiet place and keep the end of the funnel with a balloon on your chest, towards the left centre on the skin.
• Keep the other funnel over the ear. You can hear a little beating sound.
• Make use of the timer to count the number of beats you hear in 20 seconds. Multiply this value by three to calculate how much your heart beats in a minute.
• Try doing more tests like running for 5 minutes and check how fast your heart beats.