Friction

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

Level 1 - Core idea

Verbal: Friction is a force that acts between two surfaces in contact and opposes their sliding motion. Rougher surfaces create more friction, and friction can also produce heat.

Symbolic: rough surface -> more friction (more opposition); smooth surface -> less friction (less opposition)

Visual: Slide a matchbox on a wooden table, then on a rough towel — it slides farther and faster on the smooth table because of less friction.

Level 2 - Going deeper

Notice where you see this idea at home, at school, and in your neighbourhood — connecting the concept to daily life makes it easier to remember and use.

Level 3 - NCERT anchor

NCERT EVS Looking Around 4 — outdoor play chapters show how toy cars and balls move differently on grass compared to a smooth cemented floor.

Why does a marble roll farther on a smooth tiled floor than on a rough doormat?

Step 1 - The tiled floor is smooth; the doormat is rough.
Step 2 - Rough surfaces create more friction, which opposes motion more.
Step 3 - Less friction on tiles allows the marble to keep rolling longer.
Answer: The marble rolls farther on tiles because there is less friction there.

Why do cricket players wear spiked shoes on the ground?

Step 1 - Spikes dig slightly into the soft ground.
Step 2 - This increases friction between the shoe and the ground.
Step 3 - More friction gives a firmer grip and prevents slipping.
Answer: Spiked shoes increase friction so players do not slip.

• What is friction?
• Which gives more friction — a rough surface or a smooth surface?
• Why do our palms feel warm when we rub them together quickly?
• Name one object designed to increase friction so we do not slip.
• Stretch: Why is it harder to walk safely on wet, smooth tiles than on a dry rough mat?

Revision tip: Rub your palms together and feel the warmth before answering questions on friction.

Open the Practice tab for graded questions on Friction.