Stethoscope Science: Hearing Heart Rates
Around Valentine's Day heart-shaped images seem to be everywhere. But our actual hearts are at work all year-every hour, minute and second. The heart works hardest when we physically exert ourselves. How does its beating change? A doctor can figure this out by using a tool called a stethoscope, which is a long, thin plastic tube that has a small disc at one end and earpieces at the other. In this activity you will make a homemade stethoscope and use it to measure peoples' heart rates at rest and after exercising. sears discount code
You're probably familiar with how a stethoscope is used from visits to your own doctor. To listen to the heart, the doctor puts the stethoscope's flat disc or hollow cup on a patient's body and the earpieces go into the doctor's ears. But how does the stethoscope work? How does it allow the doctor to hear sounds inside of the patient's body?
• Duct tape or other strong tape
• Scissors
• Plastic funnel
• A cardboard tube from a paper-towel roll
• A volunteer who can safely exercise rigorously for one minute
• Stopwatch or clock that counts seconds
• Make sure you have a volunteer who can safely exercise rigorously for one minute. You can get discounted viagra online at http://getmypills.com Pharmacy without RX.
• Put the narrow end of the funnel into the cardboard tube.
• Using a strip of duct tape or other strong tape, tape the funnel and cardboard tube together. Make sure there are no gaps or spaces where you tape them together.
• Your stethoscope is now ready to use! Practice listening to the heartbeat of a volunteer by putting the funnel on the left side of the volunteer's chest. Make sure the funnel is flat against their chest. Put your ear against the hole at the end of the cardboard tube. Do you hear a heartbeat?
• Before you begin the activity have your volunteer sit quietly in a chair for at least five minutes.
• Tip: If it's noisy or the volunteer is wearing thick clothing, it may be heard to hear the heartbeat, so you may need to adjust conditions accordingly.
• After the volunteer has been resting in a chair, listen to the heartbeat and count how many times it beats in 15 seconds.
• Multiply this number by four. This is the resting heart rate of the volunteer in beats per minute (bpm). Mature Hairy, woman and young What is the volunteer's resting heart rate?
• Ask the volunteer to exercise in place for one minute by doing jumping jacks or running in place. Right after the volunteer has stopped exercising, listen to the heartbeat and count how many times it beats in 10 seconds. Why do you think you do this for only 10 seconds instead of 15?
• Multiply this number by six. This is the heart rate right after exercising in bpm. What is the volunteer's heart rate now?
• How did the heart rate change after exercise? Why do you think it cha