Heart Rate Investigation

Our heart is a muscle which functions as a very powerful pump to transport blood around the body. It beats somewhere between 60 and 100 times a minute, but can beat even faster than that if needed. Nutrients and oxygen are transported to cells in the body and waste products taken away. The right side of the heart receives blood from the body and pumps it to the lungs, while the left side pumps from the lungs to the rest of the body.

Just before each beat the heart fills with blood, it then contracts which squeezes the blood along.

When we need more energy,  for example to run, the heart beats faster to pump more oxygen around the body. When your heart beats it sends a wave of pressure through all of your veins in your body. You can feel this pressure in some areas of the body (such as when a vein passes over a piece of bone). We call this your pulse. One place to feel your pulse is on your wrist in a straight line at the base of your thumb.

If you count your pulse for 1 minute that gives you your pulse rate. You can do it for shorter periods but you must remember to then convert it to beats per minute. So if you time it for 30 seconds you would have to double your pulse count to get the number of beats per minute.

When the heart beats faster, the pulse rate is higher.


  • A stopwatch
  • Pen/Paper


  • Record pulse rate at rest, by counting pulse beats on the wrist for 1 minute.
  • Run up and down the hallway or do star jumps for 1 minute.
  • Immediately record pulse rate again
  • Rest for 1 minute.
  • Record pulse rate again.
  • How long does it take for pulse rate to return to the resting level?

  heart rate

Helps child to understand.

That the heart pumps to circulate blood around the body.

The effect of exercise on pulse rate.

For younger children, you could draw around them and then show them where their heart is on the picture.

Science for kids

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This post is part of our special summer science series.

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Day 2 – Slipping and Sliding

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