Introduction: Extending Grabber

By 30+ STEM Projects for Kids
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You can find the lesson plan, 1-page project sheet, and more project ideas at STEM-Inventions.com


Step 1: Materials

For the basic example, you'll need:

Designable components:

For testing:

  • 2 cups

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Step 2: Assemble and Reinforce the Beams

  1. Create four beams by inserting the craft sticks into the pieces of straws.
  2. Leave a small gap (about 1mm) between the ends of the craft sticks.
  3. Break off a 3-4" piece of skewer. Get a piece of masking tape. Use both hands to hold the tape and stick it onto the skewer. Without letting go of the tape, apply it to the straw piece. Fold the other half of the tape over the skewer.
  4. This will reinforce the connection between the sticks. Without it, the straws might bend and cause the grabber to be inoperable.
  5. Young students may have trouble with this step.
  6. Repeat with all four beams.

Step 3: Connect the Beams

  1. Use the pointed end of the skewer to carefully pierce the center of the straw.
  2. Pierce another straw piece with the same skewer.
  3. Pull the skewer most of the way through, then break off the skewer, leaving a 2-3" piece connecting the two straw pieces. By pulling the skewer all the way through, the pointed tip can be reused.
  4. Repeat for the other two beams to create two 'X' shapes.
  5. Repeat this process to connect the two 'X' shapes together as depicted.

Step 4: Design the Grabber

Use pieces of craft sticks, pipe cleaners, and/or rubber bands to improve the grabber's grip. This part of the project is more open-ended.

Step 5: Test

Tape two cups together as depicted.

Try to pick up the cups. If this proves too easy, then improvise new challenges.

Avoid picking up objects that weigh more than a few ounces.

Step 6: Safety, Tips, and Troubleshooting

  • The skewer pieces may be pointed. Don't allow students to try to grab at each other or wave the skewers above shoulder height.
  • Be sure that students create and reinforce the beams before assembling. Students may be eager to assemble the beams, but the reinforcement step is important for this project to be durable.
  • The cup challenge may be easy for many students. Improvise a variety of challenges to encourage redesign, such as picking up a large marker, a rolled up piece of paper, your keys, or other small objects.
  • If the joints are falling apart, you can wrap tape around the skewer pieces to prevent the straws from slipping off.