- paper clips
- rubber bands
- hair ties
- binder clips
- wire twist ties from tying fruit or vegetable bags
For testing the forceps:
- Sheet of paper with a 2-inch square drawn on it
- Four dominos or similar size rectangular blocks
- One nickel, penny, dime, and quarter
- Your prototype forceps can pick up and remove a nickel without knocking down any of the dominoes that define the “operating” space.
- For better success, pick up and remove other types of coins with thinner edges (such as pennies or dimes)
There are 3 constraints for this challenge (an engineering constraint is a limitation on your design):
- Use only the materials listed, but you don’t have to use all of them.
- The dominoes have to stay standing in place as you perform the procedure.
- There can only be one coin at a time inside the square.
Brainstorm Think about different shapes of forceps and the purpose of their designs. Do an image search on the web to see what different forceps look like. You’ll see that forceps come in a huge assortment of shapes and sizes, depending on the specific purpose. Some clamp blood vessels or tissue. Others remove tiny objects like splinters or bits of bone. Some dress or undress wounds; others help the surgeon stitch together incisions. And that’s just for starters! Forceps generally fall into two categories: ring and thumb. Ring forceps are designed kind of like scissors, with different shapes and points at their ends. Thumb forceps look and work more like tweezers, but they also have a wide range of tips depending on their function.
- Study some pictures of forceps and imagine which design would be best for picking up a coin inside a small space.
- Draw a few designs that you think could work for the “operation” you are about to perform.
Build and Test
- Make your forceps. They have to be strong enough to grasp a coin, with ends that won’t allow the coin to slip once you’ve grasped it. It also has to operate precisely enough that it won’t make the dominoes fall over.
- To test your design, set one domino upright on each side of the square. Place one nickel flat in the middle of the square. Now, use your forceps to remove the coin without any dominoes falling.
Evaluate and Redesign
- How well did your forceps work? Did you see some tweaks you could make so that it grasps a coin more firmly or precisely? Engineers rarely get their design right the first time and they learn a lot from their mistakes.
Make Changes and Try Again!
- Make improvements and try again.
If removing a nickel goes well, try a different coin. The different thickness and size will offer a new challenge to the design of your forceps. Share Your Results with a Teacher, Parent/Guardian, or DiscoverE! You can email photos to DiscoverE at social@DiscoverE.org