more dates coming soon!

Paper Friction

Friction is a force that you’ll find increases, page by page

Australian Curriculum links

• Science > Physical Sciences > Year 4 > ACSSU076

You’ll need

• Two identical small note pads

Try this

1. Starting from the bottom of the pads, interleave the pages from each pad.
2. Keep going until the two pads are completely interleaved.
3. Try to pull the two pads apart, while holding them by their “spines”. Ask a friend to try to help you to pull them apart. You should find they are quite firmly stuck together.

Further investigation

• Try using a range of different papers e.g. used magazines or old text books. Does one type of paper give more friction than another?
• What is the minimum number of pages in the pads that you need to interleave to make them difficult to separate?

What’s happening?

The pads are stuck together due to a force called friction. Put simply, friction can be thought of as the resistance encountered by something when it is moved over or across another objects. Friction holds the pages of the pads together and the only way to separate them is to take them apart page by page, the same way you put them together.

There are three main types of friction:

• Static friction, which you experienced in this activity, is the resistance that causes two bodies not to slide past each other.
• Kinetic friction is the resistance when two bodies begin to slide, such as when you fall off your bike and grind your knees. Kinetic friction can create heat – try rubbing your hands together – and, if the surfaces are of different hardness, a lot of damage to the softer body.
• Rolling friction is the resistance of two objects that are in contact but are then peeled away from each other, such as ripping apart Velcro tape or a wheel rolling along the ground. Rolling friction is generally the weakest form of friction.

Further information

Mythbusters tried this experiment using interleaved phonebooks. The force needed to try and separate the books was quite immense. You can check out the results on this YouTube clip