Make It Move

Something needs to be moved, but you cannot touch it with your hands - it is too far, too high, or in an awkward spot. Design a tool that can reach out and move or lift a small object for you, worked entirely from your end.

Machines that reach, grab, and lift all rely on levers and pivots - the same parts in your grabber. A small movement at your hand becomes a bigger or stronger movement at the far end.

• Cranes
• |Excavators
• |Scissors
• |Claw machines
• |Elevators
• |Robotic arms

Simple machine

A basic tool that makes work easier, like a lever, a pulley, or a wheel.

Lever

A stiff bar that turns around a fixed point to lift or move something.

Pivot

The fixed point a lever turns around, also called a fulcrum.

Mechanical advantage

When a machine lets a small push move a bigger load, or reach farther than your arm can.

Motion

How the parts of a machine move - sliding, turning, opening, or lifting.

• Cardboard
• Brass fasteners
• String
• Straws
• Tape
• Popsicle sticks
• Rubber bands
• Cups or small objects to lift

Materials behave differently. Use this to decide which material does which job.

Engineers plan before they build. Work through these before you pick up any tape.

1. 1Draw your idea before you build it. A rough sketch is fine.
2. 2Label the strongest part of your design, and the part you are least sure about.
3. 3Predict what might fail first when you test it.
4. 4Decide which material goes where, and why that material fits that job.

These are guides, not rules. Two students can follow them and build very different designs - that is the point.

1. 1

   Pick your machine: a grabber that opens and closes, or a crane that lifts with a string. Both use the same ideas.

2. 2

   Find your pivot - the point your parts turn around - and join two pieces there with a brass fastener.

3. 3

   Make handles or a pull-string long enough to work the machine from your end without touching the object.

4. 4

   Add the grip or hook that actually holds the object.

5. 5

   Test the movement early and often. Joints usually need adjusting before the machine works smoothly.

A design is only finished when it passes a fair test. Run each test the same way every time.

• Reach test

  Measure how far the grabber extends from where your hand holds it.

  Measure: Reach in centimeters

• Grip test

  Try to pick up the object and hold it in the air for five seconds.

  Measure: Does it hold, slip, or drop the object?

• Place test

  Move the lifted object to a target circle and let it go.

  Measure: How many out of five tries land in the target

Write down what happens each time you test. Your numbers tell you what to improve. Print this page or copy the table into your notebook.

Your first version is a prototype, not the final answer. Change one thing based on what failed, then test again.

• If the arm flopped or bent, use a stiffer piece or add a second layer of cardboard.
• If a joint was too loose it wobbled; too tight it would not move. Adjust the fastener until it is snug.
• If the grip kept dropping the object, add texture, a hook, or a deeper cup to hold it better.
• If a crane string slipped, tie it off or wind it around a spool for control.

1. 1Was your design strong, or easy to move?
2. 2Where did it bend?
3. 3What part acted like a lever?
4. 4What made the movement better or worse?
5. 5How could you improve the grip or lifting power?

• Add a second joint so your grabber can bend around a corner.
• Redesign the grip so it can pick up a rounded object like a ball.
• Make the crane lift the object straight up instead of swinging it.

Running this lesson? The parent & teacher guide has setup, materials prep, safety notes, common failure points, and questions to ask.