Part 1 — Lessons (30)
1. The Human Body Systems
Your body has systems that each do an important job:
- Digestive system — breaks down food for energy (mouth, stomach, intestines).
- Respiratory system — takes in oxygen and breathes out carbon dioxide (lungs).
- Circulatory system — the heart pumps blood through vessels to every part of you.
The systems work together to keep you alive and healthy.
2. The Digestive System
The digestive system breaks food into tiny pieces your body can use.
Food goes from the mouth down the food pipe to the stomach, then into the intestines, where the goodness is taken into the blood. Waste leaves the body at the end.
3. The Respiratory System
The respiratory system helps you breathe.
You breathe in oxygen through your nose and mouth. It travels down to your lungs, where oxygen passes into the blood. You breathe out carbon dioxide as waste.
4. The Circulatory System
The circulatory system moves blood around your body.
The heart is a muscle that pumps blood through tubes called blood vessels. Blood carries oxygen and food to every part of you and takes away waste.
5. Forces and Motion
A force can start, stop, speed up, slow down or change the direction of a moving object.
Gravity pulls things down to Earth. Friction slows things that rub together — it helps your shoes grip the ground.
Try this: Roll a ball on tile, then on grass. Where does friction stop it sooner? (Grass.)