July 19th, 2024

Science Smarts: An experiment in honour of dad

By Patty Rooks on June 15, 2024.

There is a big day fast approaching this weekend – Father’s Day of course. In celebration of all the fathers out there, I thought I would share one of my favourite experiments. Allow those young scientists at home to surprise you with this activity – you can ask them, is it science or is it magic? Let’s get started!

*Remember to ask an adult before doing this experiment.


– One large empty metal (preferably) coffee can with a plastic lid

– 2 large washers

– Extra large twist tie

– Several really long rubber bands (in case they break)

– Large nail

– Hammer

– Tape

– Scissors

– Science helper


1. I do not want you to cut yourself on the sharp edges of the coffee can, so please use the duct tape and cover the entire edge all of the way around the can.

2. It is time to ask your science helper for some assistance – using the hammer and nail, make two small holes in the bottom of the coffee can. The holes should be in the centre of the can in a straight line, approximately 10 centimetres apart.

3. Repeat #2 for the lid.

4. Using the scissors, cut the rubber band in half.

5. This is a bit tricky, so be patient. Take the rubber band and thread it through the holes in the can and lid. (note: if one rubber band is not long enough, you may have to tie two together in order to get this to work) .

6. Tie the ends of the rubber band in a secure knot.

7. With the twist tie, place the weight in the middle of the rubber bands. (You may need some help here as the rubber bands will keep snapping the lid closed, slamming your fingers in there – trust me!).

8. Carefully secure the lid on the coffee can.

9. Take the can and roll it on a long flat surface such as the ground.


11. Here is where you can investigate if it is magic or not – ask dad what he thinks. Set up your experiment up, BUT as you roll the can, tell them that you can make it come back to you just by whistling. Roll the can, whistle for it to come back. As it rolls back, it will appear as if the can is responding to a command. No, this is not magic, it is science!

What is going on?

Sometimes, we mistakenly say that our experiment was magic, but it was really science. There is often a logical scientific explanation for what is going on. For instance, in this experiment, as the can rolls, the weight doesn’t spin. Instead, it acts as a stationary anchor. As the can spins, the elastics twist up against the heavy metal washers. By the time the can stops, a considerable amount of energy has been stored in the rubber band twists. When the strand unwinds, the released energy is changed in the motion of the can’s return.

Patty Rooks, senior scientific consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: 12 826 11th Street SE, Medicine Hat, AB, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.

Share this story:

Notify of
Inline Feedbacks
View all comments