We’ve been doing some really fun science experiments this summer! I’ve specifically been looking for experiments that have an element of demonstration or guided data gathering, evaluation, estimation, and then testing. I want the kids thinking about what they’ve seen, and how they can use that info! For reference, this experiment was conducted with rising 1st and 4th graders.
The first experiment we tried this summer came to us thanks to our library. During COVID they’ve been giving out little bags with science experiments to families who are picking up kid’s books.
I took the materials, googled a bit, and designed our experiment. The kids made a catapult. We tested it with three different types of projectile, in three different positions, and then they got to look at their data and decide which configuration was the best.
grab your experiment printable here
Would you like to do this experiment too? Here’s how:
Materials:
– 8 popsicle sticks
– bottle cap
– glue
– ruler
– rubber bands
– cotton ball
– pom-pom
– small ball made from foil
– meter stick
– sidewalk chalk
1cm markings 
bottlecap attached 
our scale
Pre-Experiment Preparation:
Make the Launching Stick
Take a popsicle stick. Use the ruler to draw 1cm markings along the length of the popsicle stick. At one end of the popsicle stick, glue on the bottlecap.
Draw the Measuring Scale
Outside, use the sidewalk chalk and meter stick to draw a scale. We drew lines every 10cm for about 120cm. We needed to draw at least 2m worth of lines!
the stack 
perpendicular launcher 
attached base
Procedure:
Stack 6 popsicle sticks and secure them together by wrapping each end with rubber bands.
Take the launching stick, secure it perpendicular across the top of the stack at the middle marking. Use a rubber band crossed in an X to hold the sticks in place.
To secure the base, attach a stick to the non-bottle cap end of the launching stick with a rubber band. The stack of sticks is between and perpendicular to the base and launching sticks.
Test your catapult by placing a cotton ball in the bottle cap, push down a little bit, and let go.
Experiment:
Place the catapult at the starting line. Place the cotton ball in the catapult, launch and record the distance traveled.
- Repeat with the pom-pom and foil ball.
- Move the stack of sticks towards the bottle cap. Repeat the experiment with the three ball types and record results.
- Move the stack of sticks further away from the bottle cap. Repeat the experiment with the three ball types and record results.
| Position of Stack | Distance – Cotton Ball | Distance – Pom-Pom | Distance – Foil Ball |
Making Predictions:
Based on their observations, the children should choose the stack position and ball they think with give the best results.
Build your catapult according to your prediction. Launch it and record the distances 10 times.
Results and Data Analysis:
We took a look at our 10 data points and circled our furthest fling. We had a little discussion about the distances, and what other factors (the wind!) affected our results.
After this, the little ones were finished. I asked the older ones to sum their 10 data points, and divide by 10 to find the average distance traveled.
We also plotted the 10 data points on a graph to get a visual representation of the distance variance.
We really enjoyed this experiment! We hope you do too!