Activity 9.3

Today, we're going to learn about friction, which is a force that opposes motion between two surfaces. Can anyone tell me their understanding of what causes friction?

I think it has to do with how rough or smooth the surfaces are.

Exactly! Friction acts based on the surface characteristics. When we do our Activity 9.3, we will see how different surfaces affect the motion of an object.

Why do some surfaces make it easier to slide than others?

Great question! It’s because of the surface irregularities—rougher surfaces have more ‘grip’ which increases friction. Remember this with the mnemonic 'Rough Equals Rough,' where more roughness equals more resistance to sliding.

Now, let's start our activity! We will roll a pencil cell down an inclined plane and observe how far it goes. What's the first thing we should do?

We should make sure the incline is steady and at the same angle for each trial.

Are we supposed to use different surfaces under the cell?

Yes! We will use smooth, cloth-covered, and sandy surfaces. Each will show how the pencil cell's distance traveled differs due to friction. After rolling, let's note down our observations.

Now that we have completed the activity, what did you notice about the distances the pencil cell traveled?

The pencil cell went the farthest on the smooth surface and stopped quickly on the sandy surface.

Exactly! This shows how friction impacts motion. Remember, the smoother the surface, the less friction. Let's summarize this as 'Smooth Surfaces Slide, Rough Surfaces Resist.'

So, the surface texture plays a big part in how far an object can travel!