Getting our bearings

 Last night I changed the bearings on my skateboard, which lead us to ask some questions about friction and forces.

With dad's help, I unscrewed the wheels of the board, popped out the old bearings and replaced them with Reds Precision Skate Bearings. With the new bearings in place, we wanted to see the difference between the two.

So we screwed on my brothers old bearings on one wheel to see the difference. The video below shows how much longer the reds bearing last, this is because the reds have less friction and are more spherical in shape. 

You can see that the new bearings allow the wheels to continue spinning for longer than the old ones. The wheels all weigh much the same and the axels are all made of much the same materials so this difference in how long they spin for must be mostly down to the differences between the bearings.  Bones Redz bearings are produced to a very high standard of precision in their "sphericity" and are made of a high grade steel that is very hard wearing

Whereas, Tom's old bearings are made of a lower quality steel and may even be cylindrical rather than spherical. My old bearings seem to be better but not as good as the Redz.

Here is a quick clip of my trip to the skatepark earlier with the new bearings. They made me nervous because they made the board move about more freely. I noticed that the board would move much further than previously for the same amount of push power.