- Age:6+
- Time:20 min
- Difficulty:Easy
- Mess level:Low
- Supervision:Yes
History of Catapults
When we hear the word catapult, we probably imagine sieges on medieval castles, but catapults were actually used much before that and their design varied a lot.
But what is a catapult? In a most general sense, a catapult is a machine which purpose is to hurl objects through the air with the intent of hitting some target. And it is important it's doing that without the use of explosives.
The first designs were inspired by crossbows and the need to fire larger projectiles. Catapults in this form were first used in ancient Greece and India around the 5th century BC. Romans adopted the technology and improved its design. They started to use catapults as a sling to throw rocks on their enemies. They even used catapults to hurl carcasses so they spread disease and demoralize their opponents. But the golden period of the siege weaponry began in middle ages when the stone walls and improved defenses called for more force, precision and range. The trebuchet was invented to answer that need.
Besides classical catapult (also known as mangonel), two most popular designs were:
- Ballista - giant immobile crossbows whose projectiles were large arrows or darts made from wood with an iron tip
- Trebuchet - the biggest and the most powerful version of the catapult, it could hurl 50-100kg stones over the distance of 300m
A trebuchet - the biggest and most powerful type of catapult.
The Engineering Behind Catapults
Catapults are using the laws of physics, primarily tension and gravity to store and then release energy which hurls a projectile without the use of explosives.
Classical catapult consists of an arm with a bowl-shaped bucket attached to the end in which we put projectile. Upon release, the arm rotates at a high speed and hurls the projectile. The launch velocity of the projectile is equal to the velocity of the arm at the bucket end and the angle is controlled by stopping the arm with a crossbar. When crossbar is reached, the arm stops and projectile continues moving due to the force.
A classic catapult launched projectiles at lower angles.
Unlike the trebuchet which was well suited for launching projectiles over walls, this type of the catapult was best suited for destroying walls since it launched projectiles at lower angles.
Materials Needed for the Popsicle Catapult
Everything you need for the catapult: popsicle sticks, rubber bands, a plastic spoon and a bottle cap.
- Popsicle sticks (11)
- Rubber bands (4)
- Plastic cap
- Glue gun
Instructions for Making the Popsicle Catapult
Watch the video at the beginning of the article for step by step instructions or continue reading...
👨👧 Adult supervision needed
A hot glue gun gets very hot and can burn, so an adult should handle the gluing or supervise it closely. When it's time to fire, aim the catapult at a wall or open space - never at anyone's face - and use a soft paper ball as the projectile.
- Take 6 sticks and attach them together using 2 rubber bands (on both ends).
- Take one larger rubber band and use it to attach one stick in the middle. Wrap it around all the edges - that’s the arm of the catapult.
- Glue 2 more sticks on the edges of the construction. Glue the third one over those two, so you get a square shape.
- We can make our catapult more durable by attaching a small piece of stick vertically in the middle of that closing stick (like a tail).
- Use the rubber band to connect the tail and the arm of the catapult.
- Using glue gun, attach the plastic cap to the end of the arm
- Make a little paper ball and go test your war machine!
Before you launch, make a prediction!
What will make your paper ball fly the farthest?
Make your prediction, then tap an answer to check!
What Will You Develop and Learn
- Newton’s laws of motion
- Principles of Propulsion
- Engineering skills
- Oculomotor coordination
Key takeaways
- A catapult hurls a projectile using stored energy instead of explosives.
- Bending the arm stores elastic potential energy in the rubber band and stick; releasing it turns that energy into fast motion.
- The launch speed of the ball equals the speed of the arm's tip at the moment the crossbar stops it.
- This is Newton's laws in action - a bigger stored force gives the light ball a bigger acceleration.
- Historic designs (mangonel, ballista, trebuchet) all used the same idea at very different scales.
Frequently Asked Questions
How does a popsicle stick catapult work?
When you press the arm down, you bend the stick and stretch the rubber band, storing elastic potential energy. Letting go releases that energy all at once: the arm springs up, hits the crossbar, and stops - but the ball keeps going, flying off at the speed the arm's tip was moving.
What materials do I need to make a popsicle catapult?
Just eleven popsicle sticks, four rubber bands, a plastic bottle cap for the cup, and a hot glue gun. A small paper ball makes a safe projectile. Everything is cheap and easy to find around the house.
How can I make my catapult launch farther?
Pull the arm down further before releasing it - that stores more energy. You can also add an extra rubber band for more tension, keep the projectile light, and adjust the launch angle. Lighter balls travel farther than heavy ones with the same setup.
What is the difference between a catapult and a trebuchet?
A trebuchet is one specific type of catapult. "Catapult" is the general word for any machine that hurls objects without explosives. A classic catapult (mangonel) uses tension and launches at a low angle, while a trebuchet uses a heavy counterweight to lob projectiles high over walls.
What does the popsicle catapult teach kids?
It's a hands-on lesson in physics and engineering: how stored elastic energy converts into motion, how Newton's laws of motion work, and how launch angle and projectile weight change the result. Building it also develops fine motor skills and hand-eye coordination.
Is the popsicle catapult project safe for kids?
Yes, with supervision. The only real hazard is the hot glue gun, which an adult should handle. When launching, always use a soft paper ball and aim away from faces, pets, and breakable objects.
If you enjoyed making Popsicle Catapult and would like to do more similar activities, we recommend How to make Match Head Rocket, How to make Homemade Rocket using Vinegar and Baking Soda or How to build structures with toothpicks.
