Opening up the world of friction


Studying friction

This week we studied friction with my daughter. Friction is a force that resists movement.  That is it. It resists movement as the surface of one object slides over the surface of another object. It is very useful when, for instance:

  • Trying to move forward with the car, or bike or even walking. If there is little to no friction, like on ice, moving forward is quite difficult and may not happen at all.
  • When trying to stop movement, like when putting on brakes on a bike or car. Without friction, like, again, on ice, the movement simply continues.

It is less useful, when:

  • trying to slide down a slide
  • Iceskating

So less friction means that it is harder to stop. It is good, when you don’t want to stop and less useful when you either do want to stop or want to start movement. Solid objects have friction. Fluids have friction too. With gases (air) it is called air resistance.

Our experimentation

Daughter was a little apprehensive as I said we were going to play with friction. She did not believe one could play with science experiments. I’ve clearly been too involved and not left her enough room to play. I’ll work on that. To continue, I then promptly asked her to take her socks off and tried to pull her. She did not slide but instead toppled into my arms. I then asked her to put some woolly socks on and did it again. This time she swung between my legs and back again, because her socks slid on the floor. She laughed and we did that as many times as my hands could safely swing her. I then pointed out that you can have fun with physics, because physics describes reality.

Then my husband built us a ramp (I was trying to put the baby to sleep). Daughter chose the items she wanted to use for this experiment. We ended up having 3 cars and one woolly apple. I then asked her to form a hypothesis (basically this is a guess based on previous information) as to which would go the furthest. She thought the car with the big wheels would. I concurred. Then we tried. We let each roll down the ramp:


Our friction experiments. Can you find each participant? We did this a few times, one by one and all at once

I then put a blanket on the ramp and again asked her to make a hypothesis as to the result. Then we tried again:


More friction with the blanket

All of the participants stopped quite clearly before they had previously. I pointed out that this was due to friction. The surface of the blanket increased friction and hence the cars stopped so close to the end of the ramp.

After this I believed her to understand the principle and she could experiment at her leisure. The cars went down the ramp quite a few times without the blanket. Then they came up the ramp as well. After a bit I asked daughter if she wanted to try with the blanket to see how the cars would run uphill, but she did not. She said they would stop too soon. I concurred and said that this is due to friction and she agreed. Then we continued to play.

To solidify the concept

I will continue to remark upon friction and how, and when, it works in the days and weeks ahead just to keep it in mind and to signal her growing brain that this is a concept worth holding onto.


Physics4Kids: Friction

Science clarified: Friction

2 thoughts on “Opening up the world of friction

  1. Pingback: Opening the world of gravity and air resistance | In Search for Better Learning

  2. Pingback: Opening up the world of the states of matter: liquids – part 1 | In Search for Better Learning

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