Pick up thousands of rice grains with a pencil

Description:

Learn about friction – use a pencil to pick up thousands of grains of rice. (And no, this won’t take hundreds of years.)

Equipment needed:

A non-breakable bottle (a 20-ounce pop bottle works fine)

A pencil (it should be at or near full-size)

Rice (you’ll need almost a pound for a 20-ounce pop bottle)

A funnel

The Digital Bits Science Lab Experiment:

Use the funnel to pour the rice into the pop bottle. Leave a few inches of space at the top.

Insert the pencil into the bottle’s hole, and start stabbing!

After a few stabs, the rice will settle, and you’ll feel the pencil getting stuck in the rice as you try to pull it out.

It will take some practice and experimentation as to what type of stabs work best. (Quick stabs work well.) What you’re trying to do is to get the pencil “stuck” in the rice. If you get it stuck just right, you can carefully lift the pencil, as well as the entire bottle of rice!

This experiment teaches about friction. Friction is the resistance you feel when one object is moved against another. When you’re walking outside on a snowy day, you might step on ice and slip. The ice is slippery because there is a low amount of friction between your feet and the ice. But if you sprinkle sand on the ice, you can walk without slipping – the sand increases the friction to make walking safer.

When you stab the pencil into the rice and it “sticks”, the rice is packed against other grains of rice, with are all contained by the bottle. The friction between the rice and the pencil is strong enough to hold the pencil in place when you lift the bottle with it.

Other articles related to this topic:

• Multimeter experiments and introduction
• Hot air takes up more space than cold air
• Learn about air pressure from a leaky bottle
• Why is it easier to swim in the ocean? Learn about buoyancy.
• Multimeter experiments with electricity and water