Gears let us change rotation from one direction to another. With gears, we can turn clockwise rotation into counter-clockwise rotation, and vice versa. We can also use gears to change the speed of rotation: if you put a small gear and a big gear together, the small gear will spin much more quickly than the big gear! Also, the big gear will spin with more torque, or rotational force, than the small gear.

Suggested Materials
– Compass for drawing circles
– Cardboard with corrugations inside
– Scissors
– Glue
– Paper towel rolls or other circular objects
– Rubber bands
– Skewers
– Paper
– Pencil
– Ruler

Tips and thoughts:
– Don’t use a knife or box cutter without adult supervision. When in doubt, use scissors instead.
– If you want 2 gears to rotate at the same speed, you can put an axle through both of them!

Resources
– Simple gears out of rubber bands.
– Corrugated Cardboard Gears .
– Try out this method of making gears
– Written Instructions

Click here to take this challenge to the next level.

Linkages are machines made from pivoting joints that move in strange ways when you push or pull a certain part of them. If you can connect popsicle sticks together by poking holes in them and connecting those holes with twist ties or brass brads, you can make a linkage.

Suggested Materials
– Popsicle sticks
– Hole puncher
– Twist ties or brass brads to connect the popsicle sticks
– Cardboard
– Scissors

Tips and thoughts:
– Which joints of your linkage do you want to be stuck in place? Which do you want to allow to move? The choice is yours. One easy way to stick certain joints in place: Attach those joints to a background of cardboard behind the linkage.

Resources
– Video for Younger Students.
– Video for Older Students.
– Written Instructions.

Click here to take this challenge to the next level.

Conveyor belts let us move objects over long distances. If you’ve ridden on an escalator, you’ve ridden on a conveyor belt! Every conveyor belt gets cranked by a rotating motion, which causes a straight motion along the belt. For example, escalators are powered with rotating motors, but they move people in a straight line.

Suggested Materials
– Cardboard
– Scissors
– 2 skewers or pencils
– Glue
– 2 cylinder-shaped objects. For example, a single paper towel tube cut in half.
– Paper, fabric, or any other flexible sheet

Tips and thoughts:
– Don’t use a knife or box cutter without adult supervision. When in doubt, use scissors.

Resources
– Video for Younger Students
– Video for Older Students
– Written Instructions

Take this challenge to the next level:
– Try using your conveyor belt to transport objects from one place to another. How can you use your conveyor belt to make a chore more easy or convenient?
– Normally, we crank one of the ends of our conveyor belt, and the result is straight motion of the belt. But we can make this happen in reverse; if we move the belt straight, then the crank will turn. How might you use this motion? Could you use it to recharge a hand-crank flashlight or do something else?

Pulleys let us take straight motion and redirect it so that it moves in a different direction. Cranks let us take rotational motion and create a straight pull, similar to conveyor belts.

Suggested Materials
– Cardboard
– Scissors
– String
– Painter’s tape
– Glue
– Pencil

Tips and thoughts:
– See this video for an explanation of mechanical advantage. With enough mechanical advantage, you’ll no longer be limited by your own strength, but instead simply by the strength of the materials you used to build the pulley or crank.
– Both pulleys and cranks can work using the same mechanism: a pencil stuck between 2 cardboard walls. See our Make it! DIY video on pulleys for how to make one.
– Once you’ve made your pencil between 2 cardboard walls, you can run a string through it as shown in the above video to make a pulley.
– If you want to make a crank instead, tape one end of your string to the pencil. Now the string will shorten or lengthen as you turn the pencil!

Resources
– Video for Younger Students
– Video for Older Students
– Written Instructions

Click here to take this challenge to the next level.

Your mission is simple: make a cardboard hand move to touch your own for a high-five. But how will you do it? With gears? Linkages and levers? A conveyor belt? A pulley? Or a newfangled contraption of your own design? The choice is yours!

Suggested Materials
– Painter’s tape
– Hole puncher
– Glue
– Skewers
– Twist ties or brass brads
– Paper towel rolls or other circular objects
– Scissors
– Popsicle sticks
– Compass
– Tape
– Pencil
– Ruler
– Paper
– Rubber bands
– Cardboard

Tips and thoughts:
– Here’s an example of an advanced high five machine that uses electronics.
– Remember that your high-five machine will need to be hand-powered, unless you have the luxury of a motor. How will you power your machine so that its hand moves?

Resources
– No new resources today! For this challenge, pick one of the mechanisms from Monday through Thursday (or 1 through 4) and rewatch the videos for that mechanism. Which mechanism do you want to use to make the cardboard hand move? Where do you want to attach your cardboard hand to the mechanism? Put a trick in your high five machines, like “down low” or “too slow!”