In the year 1816, Rene Laennec discovered the Stethoscope. Before the discovery of stethoscope doctors used to hear heart beat by keeping ear on the chest of the patient. Laennec found that paper tube helps to hear the heart beat perfectly. Then he used a bamboo instead of paper tube to hear heart beat. Laennec called it stethoscope.

Activity-3

Let us repeat the work done by Laennec.

Make a paper tube 10 inch long and one inch in diameter. Keep one end of it on the chest of your friend on a point one inch to the left side to the centre around 6 inches below from his or her neck. Keep your ear at the other end. Listen carefully and count the heart beats for a minute.

Also count down your friend’s pulse rate. Note observations of at least 10 students of your class in the following tabular form.




Let us plot histogram on heart beat and pulse rate of different persons as shown in the sample graph. Here

blue bar indicates heart beat, red bar indicates pulse rate.

What is the relationship between the heart beat and the pulse?

Can we say, the pulse rate is always equal to the heart beat?

You might have studied there is a relation between pulse rate and heart beat.



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