Ping Pong Pickup Challenge

The objective of the 2023 Science Buddies Engineering Challenge is to build a device that can pick up a ping pong ball and retrieve it by bringing it back over a start line and placing it on the floor. Figure 2 shows several example devices. If you have not already done so, watch the video for an overview of the challenge before you proceed.

four different grabber designs using the allowed contest materials. One is a claw with two fingers activated by pulling a string. One uses two paper clips as a fork to pick up the ball. One has two separate pieces, a scooper and a rake. One is a 'scissor lift' design with curled pieces of paper at the end to grab the ball.

Figure 2. Several different tool designs.

Rules

1. The ball and the start line must both be on the floor.
2. The ball must start a minimum of 10 cm from the start line (Figure 3). After that, you can increase the distance for subsequent trials.
3. The ball must be placed directly on the floor. You can place a small square of tape around the ball to prevent it from rolling away and make it easier to know where to place the ball during trials.
4. The ball cannot be modified in any way.
5. The device must be portable. It cannot be taped or otherwise anchored to the ground or another surface like a piece of furniture.
6. Only one person can operate the device during a trial. It does not have to be the same team member for each trial.
7. No part of your body can cross the start line at any point.
8. The ball cannot touch any surfaces or objects other than the floor and your device.
9. After the ball has been picked up, no part of the device or the ball can touch the ground or any other surface (walls, furniture, etc.) in front of the start line. The device and/or ball may touch the ground behind the start line.
10. The ball must remain in contact with your device and cannot become airborne at any point while it is still in front of the start line.
11. You cannot touch the ball directly at any point once the trial has started, even after you have brought it back behind the start line.
12. For a successful trial, the ball must be picked up, brought back behind the start line, and placed on the floor.
13. Nothing can remain stuck or attached to the ball after it has been deposited behind the start line.

A side-view diagram of a person standing on the floor and holding a grabbing device, reaching for a ping pong ball that is at least 10cm away. No part of the person's body can cross the start line on the floor. The distance is measured from the start line to the closest side of the ping pong ball.

Figure 3. A side-view diagram of the setup for the ping pong pickup challenge.

Design

Before you start building anything, it is a good idea to brainstorm different designs. Try sketching your designs out on paper (paper used for sketching does not count toward the total used to build your device). Remember that there is a potential trade-off in your design. Your score depends on both how far the ping pong ball is from the start line and how much material you use to build your tool. So, while you can make your device longer, that will also use more material. Can you figure out how to efficiently use material to make your device as long as possible? Can you make sure that your device is still sturdy and does not collapse under its own weight if it gets too long?

Build

Once you have decided on a design, it is time to start building. You might want to start with a shorter device before you try increasing its length. Your design might not work as you planned, and this is OK! Engineers do not always get things right on the first try. If your device does not work like you thought it would, you can modify it or even go "back to the drawing board" and start over with a new design. Only materials used in your final design count when calculating your score, so make sure you keep track of the materials used in each version of your device.

Test

When you have finished building your pickup tool, place the ping pong ball on the floor (remember that you can surround it with a small square of tape to prevent it from rolling; this also gives you a clear starting location for the ball each time). Mark a starting line on the floor either with a piece of tape or an object like a pencil (make sure the line is at least 10 cm from the ball). Stand or kneel behind the start line and try to pick up the ball while making sure no part of your body crosses the line. Try to pick up the ball, bring it toward you, and place it on the floor behind the start line. Observe your device's performance as you test. Do you have any trouble picking up the ball? Do you have any trouble moving the ball without dropping it once you have picked it up? If your tool did not work well, think about ways you could improve it. If your tool did work, think about how you could make it longer.

Official Test

When you are ready for an official test, use a tape measure or meter stick to measure the distance between the start line and the closest side of the ball in centimeters. Write this distance down. Make sure you have counted all of the materials used in your device and written them down. Then, try to retrieve the ball while making sure you follow all the rules. If you break any of the rules (part of your body crosses the start line, your device touches the ground after picking up the ball, etc.), you have to put the ball back and start over. If you successfully place the ball on the ground behind the start line without breaking any of the rules, you are ready to calculate your score.

First, tally up the total quantity for each material used in your device. Remember that materials used in previous iterations do not count, only materials used in the device that you used for the official test.

Next, add up your material points cost using these values:

1. Paper: 5 points per sheet (rounded up to the nearest whole sheet)
2. Paper clips: 1 point each
3. String: 1 point per 50 cm (rounded up to the nearest 50 cm)
4. Tape: free

Finally, calculate your score using this equation:

For example, a device that uses two pieces of paper, two paper clips, tape, and no string would have a material points cost of:

If the device picked up the ball from a distance of 30 cm, the score would be:

You can try improving your device (making it longer and/or using less material), grabbing the ball from farther away, and repeating the official test as many times as you would like to get a higher score, but you can only submit one score per team.

Submitting Your Score

See the 2023 Science Buddies Engineering Challenge page for instructions on how to submit your score and prize details.