Teacher sheet · Ages 10–11 · about 45–50 minutes
Muscles: three kinds, pairs and tiredness
Lesson page: echoesof.science/school/muscles/ages-10-11/ · Pupil worksheet: echoesof.science/school/muscles/ages-10-11/print/
Learning aims
- Name and locate skeletal, smooth and cardiac muscle.
- Explain voluntary and involuntary muscle.
- Explain antagonistic pairs (flexor/extensor, prime mover/antagonist).
- Carry out a fair test on muscle fatigue and describe a pattern.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: list everything your muscles have done since you woke up. |
| 10 min | Read the text; sort the class list into voluntary and involuntary. |
| 20 min | Clothes-peg fatigue fair test in pairs. |
| 5 min | Game: Which kind of muscle? |
| 5 min | Quiz. |
Materials for the experiment
- One spring clothes peg per pair (all the same kind)
- A stopwatch or classroom clock with a seconds hand
- A pencil and the results table
Safety: Use ordinary wooden or plastic pegs, not strong clips. Squeeze only your own fingers' peg, never someone's skin. Stop if your hand hurts (tired is fine, pain is not). Pupils with a hand injury can be the timer and counter.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| Muscles push and pull. | Muscles can only pull (contract); a partner muscle pulls the other way. |
| Only skeletal muscles are 'real' muscles. | Smooth and cardiac muscle are muscle too: they work without us thinking about it. |
| A tired muscle is damaged. | Fatigue means the muscle cannot keep contracting for now; after rest it usually recovers. |
Worksheet answers
- Skeletal (arms, legs, face), smooth (stomach, intestines, blood vessels), cardiac (heart).
- Muscles can only pull; a flexor pulls to bend the joint and an extensor pulls to straighten it again.
- Usually fewer squeezes in each round: the muscles are getting fatigued.
- So that only one thing changes (the rounds without rest); otherwise a different peg or hand could cause the difference.
Quiz answers
- Where is smooth muscle found? In the walls of the stomach and blood vessels. Smooth muscle lines the stomach, intestines and blood vessels.[1]
- Which kind of muscle can you control when you want to? Skeletal muscle. Skeletal muscle is voluntary.[1]
- What does an extensor do? Straightens a joint. Extensors straighten a limb; flexors bend it.[1]
- What connects a muscle to a bone? A tendon. Tendons are strong bands that connect muscles to bones.[5]
- Why do you shiver when you are cold? Muscles make heat when they work. Skeletal muscles produce heat, for example when shivering.[3]
- In the peg test, what must you change between rounds to keep it fair? Nothing: same peg, hand and time. Only the number of rounds without rest changes.[4]
Going further
Repeat the test with the other hand. Is your writing hand better? Make a class bar chart of the means.
Sources used in this lesson
- [1] Your Muscles (KidsHealth (Nemours Children's Health)): reliability Medium-high
- [2] Anatomy and Physiology 2e, 10.1 Overview of Muscle Tissues (OpenStax, Rice University): reliability High
- [3] Anatomy and Physiology 2e, 10.2 Skeletal Muscle (OpenStax, Rice University): reliability High
- [4] Anatomy and Physiology 2e, 10.3 Muscle Fiber Contraction and Relaxation (OpenStax, Rice University): reliability High
- [5] Anatomy and Physiology 2e, 11.1 Interactions of Skeletal Muscles, Their Fascicle Arrangement, and Their Lever Systems (OpenStax, Rice University): reliability High
- [6] College Physics 2e, 9.6 Forces and Torques in Muscles and Joints (OpenStax, Rice University): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/muscles/sources/
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