Friction

• Friction is a force that resists (opposes) motion between two touching surfaces.
• Rough surfaces produce more friction than smooth surfaces.
• Rubbing your hands together and feeling warmth shows friction can produce heat.
• A ball rolls farther on a smooth floor than on a rough carpet.
• Grooved shoe soles increase friction, helping us walk without slipping.

Level 1 — Core idea

Verbal: Friction acts between two surfaces in contact and opposes their sliding motion — more roughness means more friction.

Symbolic: rough surface → more friction; smooth surface → less friction

Visual: Slide a book on a carpet, then on a tiled floor — it stops sooner on the carpet because of more friction.

Level 2 — Going deeper

Think about where you see this idea in daily life at home and school — noticing it around you makes the concept easier to remember.

NCERT anchor

NCERT Looking Around 3 play and toys chapter compares how toy cars move differently on grass versus a smooth floor, showing friction.

Why does a marble roll farther on a tiled floor than on a woollen rug?

Step 1 — Tiled floor is smooth, rug is rough
Step 2 — Smooth surface = **less friction**
Answer: **Less friction on tiles, so the marble rolls farther**

Why do cricket shoes have spikes underneath?

Step 1 — Spikes dig into the ground
Step 2 — This **increases friction**, stopping slipping
Answer: **Spikes give more friction for a firm grip**

• What is friction?
• Which surface gives more friction — rough or smooth?
• Why do our hands feel warm when we rub them?
• Stretch: Why is it harder to walk on wet, smooth tiles than on a dry rough mat?

Revision tip: Rub your palms together before answering — feel the warmth from friction.

Open the Practice tab for graded questions on Friction.