Elementary/Middle School Catapults

Growing up, catapults were a science class staple that provided a lot of fun while being an amazingly effective learning tool. Younger students are able to build their own catapult and learn about the real world examples of physical science through kinetic and potential energy, while older students can explore the calculations involved for solving K&P energy problems.

For more advanced students looking to study physics, catapults can also be used to calculate projectile motion.

No matter what they are used to teach, basic catapults offer plenty of fun both in and out of the classroom.

This project can easily be completed with a limited list of easily available items.

Supplies:

5 popsicle sticks

Rubber bands

Plastic spoon OR bottle cap

Marshmallows, marbles, pom poms, or another suitable lightweight projectile

Those using a bottle cap should also note that they will need hot glue or another adhesive.

The catapult can be constructed quickly and easily, even by young children.

First, we have to construct the lower stage of the catapult. Stack three popsicle sticks on top of each other, and rubber band at both ends as shown. Set this piece aside.

Please note that the height of this section will affect how far the catapult will launch. More sticks = more height = a further launch.

Next, we can start construction on the cross section of the catapult. To do this, stack two popsicle sticks on top of each other and rubber band as we did before, but only on one end. Use two more rubber bands to secure a plastic spoon to one of the two sticks, making sure to not rubber band the spoon to both.

Note: If you chose to use a bottle cap instead of a spoon, hot glue it to the opposite end of the stick that you rubber banded, and allow to dry.

Now that we have both the bottom base and the angled piece, we can fully assemble our catapult. Slide base piece into the angled piece until it is lightly secured by the rubber band already present. The catapult should be able to be moved without any separation.

To use, pull back the spoon gently towards the ground, and release.

While this activity is geared mostly for the enjoyment of middle and elementary school students in their study of physical science concepts, catapults are easily adaptable to suit a variety of state standard lessons.

Elementary school aged students first being introduced to the foundations of kinetic and potential energy can be shown a demonstration using the catapult. As the spoon is pulled back, students can learn that potential energy is present, and when it is released, the motion of the projectile shows a release of kinetic energy.

The attached set of flash cards should help reinforce the concept.

Middle school students can investigate the relationship between the height of the base section and the distance traveled, writing their own theories on why the change occurs.

High school students more familiar with the concepts of physical science have the increased scientific and mathematical background to begin learning how to calculate potential and kinetic energy. In the worksheet linked below, middle school students can label what type of energy use is being presented, and high school students can calculate it.