Praxis: Catch a leprechaun with a catapult and a little luck

By Medicine Hat News on March 9, 2019.

I thought I should get a head start on some STEM activities for St. Patrick’s Day which is approaching rather quickly. Those tricky leprechauns are hard to keep ahead of, but this year I think I may have found a way to catch one! I don’t know about you, but I could definitely use a bit of luck, so will be working extra hard on this activity so I can catch a leprechaun all for myself. Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– large popsicle/craft sticks

– rubber bands

– empty water bottle lid

– double sided tape or glue

– small net or Kleenex to fit in the lid (to catch the leprechaun)

Procedure

1. Take six of the popsicle sticks and stack them on top of one another.

2. Secure them in place by wrapping a rubber band around each end. You may have to use two so it is nice and tight.

3. Using two more popsicle sticks, stack them on top of each other. Again, secure them together using a rubber band on one end. Make sure it is tight and secure.

4. Slide the large stack of popsicle sticks in between the two sticks. You will make a cross looking design. Secure all of the pieces together using more rubber bands.

5. Using the double sided tape, tape the empty water bottle lid on the opposite end of the two popsicle sticks; the end that is sticking in the air. You are making a basket to hold your net to catch a Leprechaun.

6. Try this out so you are well practiced – you do not want the leprechaun to get away this year.

7. Place your net in the lid.

8. Using your finger, gently pull the popsicle stick back and release.

9. Observe what happens.

10. Did it go far enough?

11. Is the net heavy enough do you think to stop the leprechaun in his tracks?

12. Make any modifications you may need and keep practising!

What is going on?

Making a catapult is a great STEM (science, technology, engineering and math) activity for the classroom or at home on a chilly day! A catapult uses math, science and engineering in a really fun way. Did you know that a catapult is a simple machine design that uses a lever? You add force by pushing the lever arm down so it moves around the fulcrum that you let go. The fulcrum point is the point that does not move.

They are quite amazing machines as catapults store energy until you hit the trigger! The energy remains stored in the rubber band every time you stretch it out. The pull that you are feeling as you stretch the rubber band out is called potential energy. The catapult stores potential energy by stretching the rubber bands. The more energy you store, the farther your net will go. Good luck and let me know if you are willing to share your leprechaun if you are successful!

Calling all volunteers: If you have even an hour to spare, we are in need of Science Fair judges for the upcoming Science Fair as well as the Regional Science Fair on April 6. Prior experience is not necessary. Call or email me to sign up today.

Patty Rooks is senior scientific consultant at 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

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