WALT – We Are Learning To…

use potential (stored) energy and kinetic (motion) energy to design and develop a chain reaction.

WILF – What I’m Looking For…

to work in a group to set up up a Clever Lever explosion using pop sticks.

See a Clever Lever explosion! 

What is energy?

Potential energy is stored energy in the object. Kinetic energy is energy of motion.

Chain Reactions

A chain reaction is one that, once started, continues by itself. It keeps happening until it runs out of materials. It is a series of reactions where the result of the first action triggers the next reaction.

Clever Levers

Clever Levers utilize the stored energy in both popsicle sticks and rubber bands.

1. Make your first Clever Lever. Place two pop sticks on either side of one block. The block should be near the end of the sticks. Place a rubber band around the end of the sticks near the block. Now place a second rubber band around the other end of the sticks to hold the lever together. This second rubber band is your detonation point. Place the clever lever on the floor in an open area.
2. Build a second clever lever, leaving out the second rubber band. Place the open end of the lever between the sticks in the first clever lever, right next to the block.
3. Repeat Step 2 as many times as you can manage. You can build a quick chain reaction with just a few clever levers but the more levers you add the more power you will get.
4. To detonate your stixplosion remove the rubber band at the detonation point while pressing down on the free end of the sticks. Now let go!

See these steps illustrated here.

How does it work?

The key to the chain reaction comes from potential and kinetic energy. Potential energy is stored energy and kinetic energy is the energy of motion. As you weave the levers together, you are continually building potential energy. Each lever is pinned under the lever before it, creating tension in the wood. When you finally have the chain layout that you want, you let go and all of the tension and potential energy is released in a chain reaction of kinetic energy.

Group Challenge

Work with your group to design and build a Clever Lever chain reaction.

• Make your first Clever Lever and anchor it with a rubber band.
• Plan the design of your chain reaction.
  • Will it be a straight line?
  • Will it develop in several directions?
  • The more segments in your chain reaction the greater the explosion.
• Make many clever levers
• Build your layout.
• Take a photo of your layout.
• Do not detonate until the signal.
• Make a video of the explosion if possible.

How did you go?

Some Results 

Materials

• Square blocks
• Paddle pop sticks
• Rubber bands

More Mechanical Chain Reactions 

Mousetraps and ping pong balls

Amazing Chain Reactions

Cobra weave popstick chain reaction

How to make Cobra Weave chain reaction.

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For the Teacher

From the Australian Curriculum Design and Technologies
Technology Context – Engineering principles and systems

Years 5-6

Knowledge and Understanding

• Investigate how energy can control movement.
  • investigate the properties of materials to solve problems requiring the control of movement,
  • recognise the need to carefully plan and select components for a system to perform a specific task.
  • producing models using materials, tools and equipment to show how to control movement,

Processes and Production Skills

• select appropriate materials, components and techniques and apply safety procedures to make designed solutions.
• matching material and joining techniques to the design intention.

Idea and instructions from Babble Dabble Do.