🔬 Science · The Human Body

How Muscles Move Bones

Understand that muscles work in pairs to move bones: when one muscle contracts (gets shorter and pulls), the opposite muscle relaxes, and that some muscles are voluntary (we choose to use them) while others like the heart are involuntary (they work automatically)

Typical age: 7–9 years

“Can your child bend their arm and explain that one muscle is pulling while the other is relaxing — and that their heart muscle works without them thinking about it?”

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Needs first

Naming Major Bones
Muscle pairs contract to move bones; knowing named bones helps understand which muscles act on them
Bones & MusclesREQUIRED
Understanding muscle pairs builds on knowing muscles attached to bones allow movement

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