Share 1.7 Moving Your Bones (Collins Science 4)
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What two things work together so you can move?
Skeleton and muscles.
What are the muscles around our skeleton attached to?
The bones.
When a muscle gets shorter, what is it doing?
Contracting.
True or False: Muscles can push bones.
False (They can only pull).
Why do muscles need to work in pairs?
Because they can only pull, not push.
Is the elbow a bone or a joint?
A joint.
When you bend your arm, does the front muscle contract or relax?
It contracts (gets shorter/fatter).
When you straighten your arm, what happens to the lower arm?
It moves down.
How many sets of muscles control the elbow?
Two (front and back).
If a muscle is "relaxing," does it get longer or shorter?
Longer.
Describe a contracting muscle in three words.
Fatter, harder, and shorter.
Describe a relaxing muscle in three words.
Thinner, softer, and longer.
What happens to the muscle at the back of the arm when you bend it?
It relaxes (gets thinner).
What happens to the muscle at the back of the arm when you straighten it?
It contracts (gets fatter).
Muscles have to ______ to make a bone move.
Shorten (or pull).
What is the main job of the skeleton and muscles together?
To allow us to move.
