Materi 3 Science 4-Why do we need skeleton

1.3 Why do we need
a skeleton?

Grade 4
Chapter 1: Skeletons

Why do we need a
skeleton?

1. Protects organs
• Skull protects brains.
• Ribs protect lungs and heart.

2. Support skin
Our skeleton supports our body. It makes a
strong frame inside the body. We cannot
squash our body easily because of our
skeleton. It gives us body shape and makes it
firm. Our skeleton also protects our organs.

3. Make red blood cells

4. Used to create movement with muscles

Let’s compare the
skeletons!

What are the
differences?

What would Skeletons grow
happen to a
baby if his ● We grow and get bigger because
skeleton did our skeleton grows.
not grow?
● An adult’s skeleton is much
The baby will stay bigger than a child’s skeleton.
small and will not
grow into a child. ● An adult’s skeleton has stop
growing.

● Although your bones stop
growing when you are around 20,
they do constantly rebuild new
bone cells.

Comparing bones sizes!

Using a tape measure, measure the length of

your:
• Upper arm bone
• Thigh bone
• Shin bone

Bone Length in cm
Upper arm bone
Me Teacher/ Friend
Thigh bone
Shine bone

Whose bones are longer?

Look at the photo!
What’s wrong?

A fracture

• Sometimes we fall or have accidents and break
our bones.

• A broken bone is called A FRACTURE.
• Doctors take a special photo called an X-ray to

see if a bone is broken or not.
• X-rays are photos that let us see inside our

bodies.

• Fractures are always painful. Some very small
fractures may not be hurt at first, but eventually
you will feel some pain.

• When fracture heals, the bone is stronger than
before the break. This is not so. The bone will be as
strong as it was before, especially in young people,
but not stronger. In older people, the healed bone
may be weaker.

Do all animals have skeletons?

• Not all animals have skeleton.
• Worms and jellyfish do not have a skeleton.
• An animal with no skeleton is called AN INVERTEBRATE.

For examples:

Solve it!

Why do fractures in old people
take much longer to heal
than fractures in children?

Thank you

Ms. Ulfah and Ms. Ningrum