The 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 are 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 your veins. 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.
Heart Rate Investigation
How does exercise affect heart rate?
- A stopwatch
How to set up a heart rate investigation
- Record your pulse rate at rest, by counting pulse beats on the wrist for 1 minute.
- Run around outside 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 the pulse rate to return to the resting level?
Use my handy heart rate and exercise investigation results table to record your results or design your own!
This activity helps children to understand
That the heart pumps to circulate blood around the body.
The effect of exercise on pulse rate.
For younger children, draw around them on a big sheet of paper and mark where the heart is.
More human body science for kids
Did you know you can make a stethoscope with a cardboard tube and tape?
We love this DNA candy model!
Finally, how about a play dough model of the brain?
If you like this type of science experiment, you’ll love my book Gross Science which contains 60 deliciously icky experiments for kids!
Last Updated on July 4, 2023 by Emma Vanstone