Science · Stage 6

Forces, Motion and Simple Machines

Balanced forces keep an object's motion the same; unbalanced forces change it — so the way a thing moves tells you about the forces acting on it.

✦ Science📘 Stage 6 · S6⏱ ~12 min🧒 Ages 10–12★ Free to start

I can decide whether the forces on an object are balanced or unbalanced by looking at how its motion is changing.

Start the free lesson →⬇ Printable PDF

📖

The Rolling Car

Kavi perches on a toy car at the top of a ramp 🚗. "Watch this! While I hold it, it sits perfectly still — the forces are balanced. I let go and it speeds up down the ramp — now they're unbalanced! 🦉" "On the flat it rolls at a steady speed in a straight line, and the forces are balanced again. The way a thing moves tells you about the forces on it — let's learn to read it!"

🎓

What your child will learn

1Forces: a push or a pullA force is a push or a pull, and it always has a size and a direction. Tap each one to learn what it does.

2Balanced or unbalanced?Tap each card. The forces decide whether the motion stays the same or changes.

3Is the motion changing?If the motion stays the same the forces are balanced; if it changes they are unbalanced. Sort each one!

4Balanced or unbalanced?Predict the forces from the motion, then tap to check. Tap Next test for more.

🔍

A peek inside

Kavi sees a ball resting on the ground, not moving. Are the forces on it balanced or unbalanced?

The ball is not moving and it stays still, so its motion is not changing. That means the forces are balanced — gravity pulling it down is cancelled by the ground pushing it up.

Try this at home: What do we call forces that are equal and opposite, so they cancel out?

Ready to play and learn?

Start the free interactive lesson, or print the handout for screen-free play.

Start the free lesson →⬇ Download PDF

Part of Science · Stage 6 · S6 on KAVI Academy — a secular, whole-child learning platform for ages 5–12.