1. Science - Year 3/4A Autumn 2
Animals Including Humans
Fit For Success
Session 5
Teaching PowerPoint
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2. We use our muscles for everything we do!

3. When we do sport regularly it builds up the strength in the muscles we are using. Sports people do exercises to build up strength in the muscles they need.

4. When our muscles are working hard, they need more oxygen than usual
When our muscles are working hard, they need more oxygen than usual. Have you noticed that you breathe faster and more deeply when you exercise?

5. Oxygen is in the air that is all around us
Oxygen is in the air that is all around us. But how does it get to our muscles?
When we breathe in, air fills our lungs. Our lungs are two spongy bags inside our ribcage.
Place your hands over your lower ribs and take a deep breath in. What can you feel?
Your ribs move upwards and outwards as your lungs fill up with air.

6. Wind Pipe
Your wind pipe divides in two and takes the air to your lungs. When you take a deep breath, your lungs expand rather like a balloon that is being inflated
Lungs

7. Your body breathes by using a powerful muscle called the diaphragm.
When it is relaxed the diaphragm is curved upwards like this.
When you breath in, the diaphragm contracts which pulls it downwards, creating more space in the chest.

8. This diagram shows the same thing from the side.
Here the diaphragm is relaxed and there is not much space in the chest, so air is forced out of the lungs.
Here the diaphragm has contracted to make more space in the chest, so air is drawn into the lungs.

9. You can try this out using an empty plastic drinking bottle.
If you squeeze the bottle, air is pushed out because there is less space for air in the bottle.
If you stop squeezing and let the bottle return to its usual shape, air will be sucked back inside to fill the extra space.
Put your hands on your lower ribs once again and take a deep breath. Imagine your diaphragm pushing downwards to make more space in your chest, allowing your lungs to fill with air.
Now breathe out slowly, your diaphragm is relaxing (returning to its domed shape). It is squeezing air out as there becomes less and less space in your chest.

10. Once your lungs have put oxygen in your blood, it is pumped around your body by your heart. The oxygen can then reach the muscles where it is needed to give you energy.
Lungs
Heart

11. Some members of the Teignford Hockey Team say they get out of breath when running around the pitch; others report tiredness towards the end of a session.
Why might this be?

12. We could help the Teignford Hockey players by finding out whether improving their fitness levels would stop them getting so out of breath at training and matches.
Here are 2 questions we could investigate:
Do people who exercise a lot get their breath back more quickly after strenuous exercise?
Do people who exercise a lot pant less after a burst of strenuous exercise?
To investigate these questions we will need to measure people’s breathing rate which means counting how many breaths they take in a minute.

13. Measuring breathing
It is not always easy to count someone else’s breaths so you could make a breathometer to help
Stick a strip of card to the top of a small sheet of tissue paper. Then cut the tissue into vertical strips.
Hold the strip of card at the person’s eye level so the strips of tissue paper are hanging a little in front of their mouth and nose. You will notice the strips fluttering as the person breathes out.
Practise in a group of three. One person should time a minute, by saying “Start” and then “Stop” one minute later. The second person should breathe normally and the third person should hold up the breathometer and count.
Now swap roles

14. How many breaths did you take in a minute?
Anything between 12 and 20 breaths a minute is normal
This is your resting breathing rate

15. To investigate our questions we will also have to get people to do some strenuous exercise. Have you got any ideas?
Here are some you may have thought of
How will you keep it fair?

16. Let’s investigate!