4-H STEM Adventures: Challenge 3-Catapult (EC-14)

EXPLORATORY APPROACH

Encourages creativity and deductive reasoning, lacks structure, takes more time, and risks frustration for the youth. Generally best for out-of-school-time settings, large blocks of time, and youth ages 11 to 13.

	MATERIALS Craft sticks, unsharpened pencils, an empty tissue box, paint stirrers, chopsticks, straws, skewers, plastic spoons, milk caps, rubber bands, pompoms, paper cups, glue, ruler, pencil, and a recording sheet.
	VOCABULARY POTENTIAL ENERGY: Stored energy. When the rubber bands are stretched and the catapult is ready to be released, the energy in the rubber bands is POTENTIAL ENERGY.   KINETIC ENERGY: Energy of motion. When the rubber band is released and moves the catapult arm to launch the projectile, the type of energy becomes KINETIC.
	4-H LIFE SKILL RECORD KEEPING: As you perform multiple tests of each projectile, keep RECORDS to determine which projectile consistently launched the farthest. PERSONAL SAFETY: When launching, choose only soft projectiles that won’t hurt yourself, other people, your pets or your walls.

DO

YOUTH COMPLETE THE ACTIVITY

Watch the Challenge
 

GUIDED APPROACH

Provides structure, promotes good instruction-following habits, increases rate of success, and limits creative solutions. Generally best for classroom settings, finite blocks of time, and youth ages 8 to 10.

	MATERIALS 8 craft sticks, 5 rubber bands, plastic spoon, pompom, pencil cap eraser, ruler, pencil, recording sheet, and calculator (optional).
	VOCABULARY POTENTIAL ENERGY: Stored energy. When the rubber bands are stretched and the catapult is ready to be released, the energy in the rubber bands is POTENTIAL ENERGY.   KINETIC ENERGY: Energy of motion. When the rubber band is released and moves the catapult arm to launch the projectile, the type of energy becomes KINETIC.
	4-H LIFE SKILL RECORD KEEPING: As you perform multiple tests of each projectile, keep RECORDS to determine which projectile consistently launched the farthest. PERSONAL SAFETY: When launching, choose only soft projectiles that won’t hurt yourself, other people, your pets or your walls.

DO

YOUTH COMPLETE THE ACTIVITY

Watch the Challenge then follow steps one through five
 

STEP 1. IDENTIFY THE PROBLEM

Design and build a catapult that can launch a craft pompom and pencil cap eraser. Measure and record how far each lands from the catapult.

STEP 2. IMAGINE SOLUTIONS

Think about all of the possible ways you can make your catapult. Consider how you’ll build a base that is sturdy enough to hold the launch arm. You could build a frame out of craft sticks, unsharpened pencils, paint stirrers, or chopsticks. Another idea for a base is to start with an empty tissue box. Add an “arm” that can move to launch the projective. Bending a plastic spoon is one idea. Another idea is to glue a paper cup or milk cap onto a craft stick and then attach it to the base. A straw on top of a skewer will allow it to rotate, and adding a rubber band on the opposite end of the “arm” will add more power to your catapult.

STEP 5. IMPROVE YOUR DESIGN

Do you need to change anything to make your catapult work better by increasing the POTENTIAL ENERGY? You can go back to Step 1, and start the process again to make the changes to improve your catapult.
 

STEP 4. CREATE YOUR CATAPULT AND TEST IT

Try different projectile types to see which type launches the farthest. Remember to keep PERSONAL SAFETY in mind when selecting your projectiles. Projectile ideas are pompoms, eraser caps, dried beans, and popcorn kernels. Repeat the launch of each projectile at least three times to get an average (the sum of the distances divided by the number of launches).

STEP 3. PLAN POSSIBLE SOLUTIONS (SKETCH IT ON PAPER)

STEP 4. CREATE YOUR CATAPULT AND TEST IT

Try different projectile types to see which type launches the farthest. Remember to keep PERSONAL SAFETY in mind when selecting your projectiles. Projectile ideas are pompoms, eraser caps, dried beans, and popcorn kernels. Repeat the launch of each projectile at least three times to get an average (the sum of the distances divided by the number of launches).

STEP 5. IMPROVE YOUR DESIGN

Do you need to change anything to make your catapult work better by increasing the POTENTIAL ENERGY? You can go back to Step 1, and start the process again to make the changes to improve your catapult.

RECORDING SHEET (in inches)

1. Add the pompom distances: ___ + ___ + ___+ ___ = ___ (sum)
    
2. Divide the total pompom distance by 4 to calculate the average. ____ (sum) ÷ 4 = _____ (average)
    
3. Add the eraser distances: ___ + ___ + ___+ ___ = ___ (sum)
    
4. Divide the total eraser distance by 4 to calculate the average. ____ (sum) ÷ 4 = _____ (average)
    
5. On average, which went farther?   Circle one:   Pompom  |   Eraser