Tinkering
WITH CATAPULTS
TINKERING IS MINDFUL MESSING ABOUT WITH TOOLS AND
MATERIALS. THE GOAL IS TO FIND OUT THEIR POSSIBILITIES
AND LIMITATIONS. WHEN WE TINKER, WE MAKE NEW THINGS
FROM EXISTING PARTS, WE SOLVE PROBLEMS AND WE LEARN
BY MAKING MISTAKES.
DURATION:
50 minutes
GRADE:
1–3
30 students maximum
KEYWORDS:
WHAT WILL HAPPEN IN TINKERING WITH CATAPULTS?
Force
In this workshop, your students will be introduced to the basic materials for a pom-pom catapult.
They will be encouraged to design/build/test/repeat their catapult and then modify the basic
plan to try to achieve increased distance, accuracy or a goal of their own choosing. The workshop
leader will offer challenges and prompts appropriate to the experience level of each group. Elastic
Motion
Energy
Gravity
CLASSROOM ACTIVITY: COMEBACK CAN
Air Resistance
CURRICULUM
LINKS BY GRADE:
Get your students thinking about elastic energy by showing them a comeback can. The "secret" to
the comeback can is in the weight that hangs from the rubber band. As long as the weight hangs
down as the tin rolls in one direction (and doesn't flip), the kinetic energy of the rolling can will be
stored as potential energy in the tightly twisted rubber band (some energy will be transferred to
friction (heat) and sound). Once the band has reached its limit, the stored energy is released and
the comeback can moves backwards towards its starting point.
Science Content:
Grade 2 (Forces)
CURRICULAR
COMPETENCIES:
Questioning and Predicting
Planning and Conducting
Processing and Analyzing
Applying and Innovating
Evaluating
WHAT YOU NEED:
» Coffee tin (or other cylindrical container)
» A drill or hammer and nail
» Two elastic bands
» Two paperclips
»Tape
» Cotton thread or string
» Small weight (e.g. a few washers)
WHAT TO DO:
Part 1: make the comeback can
1. Drill or punch a small hole in both ends of the tin and thread the first elastic band through the hole
at the base. Secure a paperclip to the band outside of the can to prevent the elastic from slipping
through the hole. Use tape to secure the paperclip.
2. Thread the weight or washer onto a piece of string and use that string to tie together the
two elastic bands. This should result in the string holding the weight and also joining the free
end of the elastic you secured to the tin in step 1 to the second elastic band.
3. Take the other end of the second elastic band up through the hole in the lid, and use a paperclip
to prevent from slipping through the hole. Close the lid and secure the paperclip with tape.
4. Roll the tin away from you: This should “wind up” the elastic, causing the can to roll back again.
Activity continued on other side
To view our complete field trip offerings, or to book a trip, please visit scienceworld.ca/fieldtrips.
To enquire about programs for schools, contact the sales office at [email protected] or 604.443.7500.
Charitable BN: 10673 4809 RR0001
Tinkering
WITH CATAPULTS
Elastic Band
Elastic Band
Paper Clip
Paper Clip
Lid
String
Small Weight
TIP: Make sure that the weight hangs down below the point where it is tied. If it flips over as you
roll the can away from you, the elastic won’t wind up, and your can won’t come back!
Part 2: mystify your students
1. Without showing your students the inside of the can, demonstrate that it comes back when you
roll it away from you. Ask them to imagine what might be inside the can and ask how they might
test to see if their idea is correct.
2. When you eventually show them the inner workings of the can, explain how the elastic band
stores energy.
HINT: see a more detailed version of this activity at:
scienceworld.ca/resources/activities/come-back-can
MORE ABOUT TINKERING, FORCE AND ENERGY AT TELUS WORLD OF SCIENCE
Eureka! Gallery: Giant Lever, Lift Yourself
Made in Canada Exhibition (opens late April 2017)
RECOMMENDED RESOURCES:
» Science World Resources | Unit | Elastic Energy
scienceworld.ca/resources/units/elastic-energy
» Invent to Learn by Sylvia Libow Martinez & Gary S. Stager
(Constructing Modern Knowledge Press, 2013) ISBN: 978-0-9891511-0-8
» The Art of Tinkering by Karen Wilkinson & Mike Petrich
(Weldon Owen, 2013) ISBN-13: 978-1-61628-609-5 ISBN-10: 1-61628-609-1
To view our complete field trip offerings, or to book a trip, please visit scienceworld.ca/fieldtrips.
To enquire about programs for schools, contact the sales office at [email protected] or 604.443.7500.
Charitable BN: 10673 4809 RR0001