What it shows
A life-size or half-size skeleton built from waste shows the main bones of the body, how the skull protects the brain, how the ribs make a cage around the heart and lungs, and where the joints let us bend.
The science
The skeleton holds the body up, protects soft organs and gives muscles something to pull on. The skull, ribs and backbone protect the brain, heart, lungs and spinal cord. Bones meet at joints: the elbow and knee are hinge joints that bend one way, the shoulder and hip are ball-and-socket joints that turn in many directions, and the backbone is a chain of small bones (vertebrae) that lets us bend and twist.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Toilet-roll and kitchen-roll cardboard tubes (about 20)
- Drinking straws and old pens for finger bones
- Bottle caps for joints and vertebrae
- A 1 litre bottle or a paper ball for the skull
- Thick cardboard for the ribs and pelvis
- Thread, split pins, glue and tape
- A marker for labels
Safety
For this project: An adult must cut thick cardboard and poke holes for the split pins. Keep small caps away from children under 3.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
9 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Draw a simple skeleton on a big sheet of paper and decide the size of your model.
Thread bottle caps on a string, cap after cap, to make the backbone with its many vertebrae.
Use long tubes for the thigh and upper arm bones and pairs of thinner tubes for the lower arm and lower leg.
Cut curved cardboard strips for ribs and glue them to the backbone to make a cage.
Cut a flat cardboard pelvis and a pair of shoulder blades and attach the legs and arms with split pins so they can move.
Make hands and feet from straw pieces joined by thread.
Glue the bottle or paper-ball skull on top and draw the eye sockets and jaw.
Label the main bones: skull, ribs, backbone, humerus, radius, ulna, pelvis, femur, tibia, fibula.
Show the hinge joints bending one way and the ball-and-socket joints turning.
What you should see
A standing or hanging skeleton with labelled bones whose arms and legs move at the joints, showing which joints bend and which turn.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1How many bones does an adult have?
About 206.
2Which bones protect the heart and lungs?
The ribs, together with the breastbone and backbone.
3What kind of joint is the knee?
A hinge joint; it bends in one direction only.
4Why is the backbone made of many small bones?
So that it can bend and twist while still protecting the spinal cord.
Take it further
Add rubber-band muscles across the elbow to show how a muscle pair bends and straightens the arm.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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