Catapult Challenge

Investigate  What do you know about energy? Energy that is available for use is called stored energy. Examples of things with stored energy are gasoline, batteries, and food. Throughout history, engineers have used energy to build machines to send items flying through the air. These machines are called catapults and the objects they send flying called projectiles. Catapults have been used as weapons, to move heavy items from one place to another, and to release airplanes from ocean-going aircraft carriers.

Some Background Information  The first catapults were constructed by using some of the simple machines like the lever, wheel, and ramp.  Catapults were invented about 400 BC in the Greek land of Syracuse (what is now a city in Sicily)  Catapults were initially used to shoot spears or stones  The Greeks had much success with this weapon

The Challenge  For this challenge, you will use your knowledge of energy and simple machines to design and build a catapult that launches a marshmallow projectile.

Criteria:  Lighter, easier to carry catapults score higher than awkward, heavier ones  Freestanding catapults score higher than catapults that must be held down  Catapults should send the marshmallow at least 6 feet, with a higher score for longer distances.

Constraints:  Must use only the materials provided  Must complete each stage in the time allowed  Only 3 attempts are allowed, with the longest distance used for scoring

Materials:  Plastic spoons  Craft sticks  Rubber bands  Binder clips  Paper plates  Sticks or dowels  Straws  Clothespins  Unsharpened pencils  Bottle caps  Paper cups  Paper clips  Tape  Cardboard boxes

Brainstorming:  You will get a piece of plain paper and need to fold it to make four sections. You will work alone for 15 minutes to think of four different ideas for building a catapult, using the materials you just saw.  After 15 minutes, choose your favorite idea and circle it. You will be working in groups. Each group will come up with one design to build. It may be like your favorite design, or it might be a little different.

Plan:  After the group agrees on a design, draw and label a diagram of the group’s catapult. The plan needs to include a list of materials that will be needed.

Build:  It is time to build!  While you are in the classroom, you may launch your catapult only when they are facing a wall in the designated testing area. Otherwise, things or people could get hurt.

Redesign  Based on your results, what changes would you make? Draw and label the changes in a different color.

Questions to Consider  What properties of materials do you need to consider when you design?  How does a catapult get energy to store? What can you do to give it energy?  What questions do you have about the challenge?