Friction

http://www.school-for-champions.com/science/friction_uses.htm

Today’s Lesson

• Some stuff of friction• An activity on friction (will continue next

lesson)• Some more stuff on portfolios

By the end of the lesson I will:

1. Print out a front page for my Student Conference Portfolio

2. Answered the questions on the wiki to a good quality. Remember – your parents will be reading what you write!!

What is Friction?

• Friction is the ‘evil’ of all motion. It does not matter which direction something moves, friction pulls in the other direction.

• For example, Chris might be walking to the door – but ‘evil’ friction is moving in the opposite direction.

http://www.wildsound-filmmaking-feedback-events.com/austin_powers_dr_evil.html

And this means?

• To put it simple when two objects rub together, friction occurs in the opposite direction.

• Friction is actually needed for things to move. For example, it’s friction that allows something to start moving or allows it to stop moving…

Mr Fedley lied? Friction is not evil!!!! Grrrrrrr….

http://canitbesaturdaynow.com/dived/single/shocked_face/

Different Surfaces

• Different surfaces have different amounts of friction. For example, ice has less friction than carpet if the ice is flat as there is less rough surface on ice to slow down the object.

• However, if the ice is rough (not flat) then it might have more friction than carpet. It can change!!

Problems with friction

• http://www.youtube.com/watch?v=tdlewCPby8g

• http://www.youtube.com/watch?v=7pV7uKn6S4Y

How could we test friction?

• We have – – Rulers– Thunder stick (thing that measures distance)– Books– Trolley (be careful with these – expensive)– Plank

Doing The Experiment

• We will decide as a class what to do. The main thing is if we leave the classroom you need to be responsible and there is only enough equipment for 4 groups.