Three quick experiments on friction

These experiments will open your eyes and get you thinking about how the world works. They’ll get you ready for the theoretical models of friction that are to come. They cover ‘dry friction’.

Dry friction is quite different from the fluid friction that is found in lubricated bearings for example, or the friction drag as a truck pushes its way through the air. We’ll look at air friction in Week 6.

You can download instructions to the experiment in the Downloads section below. Data for the rope around a bollard experiment can be found in the upcoming analysis step.

Talking points

These experiments are effective and so simple that we assume that you have done them.

• What did you notice in your experiment with the book as it started to move?
• What did you make of the tip/slide phenomenon? Perhaps you have noticed this while moving furniture on a carpet or shifting a refrigerator?
• Those of you who use ferries might have seen how the deck-hand takes many turns around a bollard to secure the vessel against the wharf. Any sailors among you will know to take multiple turns around a winch to increase friction. Did anything else come to mind?

Share your experiment

If you attempt the experiment, take a photo and upload it to our Through Engineers’ Eyes Padlet wall. You can include a link to your photo in the comments for this step (click on your post on the Padlet wall and then copy the web address).