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Precision Ping Pong Propulsion

Students will design, construct and test a launching device to propel ping pong balls at a target that is placed within a given range.

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May the kids place painter’s tape on the floor around their launcher as a way to keep the launcher lined up the exact same way for every shot?

Yes, they may. 

The tape must impounded with the device, and mentioned as part of the impound process.  Students should not disturb the line already in place from the Supervisor, and should remove their tape from the floor when they have completed shooting.  

In the past we were only allowed to use an elastomeric material as an energy source. Are we now allowed to use simple hyrdraulics and spring loaded catapults?

The rules have changed.  See page 1, Item 3: Launching Device.

"There are no material or size restrictions."

Balls may be launched using the stored energy from sources that are: elastomeric (rubber bands), electrical (batteries), mechanical (springs), hydraulic (compressed air), etc.

Hazardous materials are not allowed.  Gasoline (fuels), lead-acid batteries or electrical energy from an outlet are NOT permitted.

The energy source must be included as part of the launcher.

How many balls are we allowed to bring to competition?

The team may impound a total of fifteen (15) regulation 40mm Ping-Pong balls.

Ten (10) white balls

Four (4) orange balls

One (1) orange ball with a black stripe

Will my team be allowed to compete if it does not have rubber feet on the bottom?

They will not.


Because of damage that was caused to the floor of the Fraser High School gymnasium during the South Macomb Tournament in 2018, this additional requirement is added to the rules.


No device will pass inspection during impound without feet, regardless of whether something sharp or abrasive is found on the bottom.  It will not be acceptable to say that competitors will not slide their device while competing. 

What is the configuration of the foam in the bottom of the pool?

The foam is about 1" in thickness.

 The foam will cover the bottom of the pool.

 The bucket will sit atop the foam.

 There will be no foam inside the bucket.

Will a team without a Practice Log be allowed to compete?


However, if the Log meets the minimum requirements, the team will be awarded 50 points.

The purpose of the Practice Log is to allow competitors quick access to information allowing them to set up quickly for a given assigned distance.

The Practice Log will also be used as a tie-breaker.  Teams should bring an extra copy to each tournament, to submit at impound.  The log will not be returned.

Is it allowable for the coach to cut a piece of PVC that is needed for the device? I am not comfortable with the kids using a saw.

We are not comfortable with the kids using a saw either.  Please keep them safe.

You are allowed to help students with the use of power tools.

Most power saws are too dangerous for an Elementary student.  Other examples, like a drill, might be a good opportunity for supervised use.

Can the team bring replacement parts, such as an extra elastomeric band, in case it breaks?

Yes, if you include them with the equipment at impound.  They should be easy (quick) to install due to the 4 minute time allowed to shoot all 15 balls.

Can we have multiple devices, due to the possibility of differing bands providing different distances?


But if you choose to use replacement "rubber bands" they should either be all installed on a single device or easily switched out due to the time constraint. Also they should be impounded with all necessary components.

Does a ball that ACCIDENTALLY falls to the floor BEHIND the line while shooting count as a shot?

If a ball falls BEHIND the line, it does not count.   The team may pick it up and fire it again.

If it crosses AHEAD of the line, it would count as a MISFIRE and may not be fired again.

If a team changes their elastomeric components to vary distance, WHEN do they make the change?

After the clock has started running.  So it must be quick and easy to do.

Can a scoring example be posted to confirm our understanding of the scoring rules?

White Ping Pong balls (10) which enter the wading pool are worth 9 points each OR 90 points (10 x 9)

Plain Orange Ping Pong balls (4) which enter the wading pool are worth 3 times 9 each OR 108 (4 x 3 x 9) points

Striped Orange Ping Pong balls (1) which enter the wading pool is worth 5 times 9 each OR 45 (1 x 5 x 9) points

Total if all are in the wading pool would be 90 + 108 + 45 = 243 points

 - - - - - - - - - - - -

White Ping Pong balls (10) which enter the center bucket are worth 25 points each OR 250 points (10 x 25)

Plain Orange Ping Pong balls (4) which enter the center bucket are worth 3 times 25 each OR 300 points (4 x 3 x 25)

Striped Orange Ping Pong balls (1) which enter the center bucket is worth 5 times 25 each OR 125 points (1 x 5 x 25)

Total if all in the center bucket would be 250 + 300 + 125 = 675 points (most possible shooting points)

 - - - - - - - - - - - - 

Submitting an appropriate Practice Log will earn a team 50 points.

 If you are late with impound 20 points will be deducted from the Teams total score.

I saw a store bought slingshot device demonstrated at the workshop. Is that acceptable?

The commercial slingshot attached to a wood base that you saw at the Ping Pong workshop would be ranked in the 2nd tier.

At the start whistle, can you move the launcher BACKWARD further away from the marked launch line?

No part of the launcher may be closer than the marked launch line. There is no restriction on how far back you can be, other than the limits of the room size.

Must the launcher be placed on the floor or can it be hand-held or on a flat (non-ramp) platform or stand?

The launcher may be hand held, may sit on the floor or be supported on a platform.

Any of these solutions are acceptable.


Is a team allowed to have more than one launching mechanism on the same device?

Yes.  However, a team cannot bring two separate devices.  And remember that the overall size must be something that two students can carry without adult help.

Will there be a count down clock or something very visible or heard for the teams to know how much of the 4 minutes they have left?

There is not a count down clock. 

As stated in section 13 of the rules: 
The Supervisor will announce when there is one minute remaining, and signal the end of 4 minutes when all launches must cease.

It would be advisable for students to practice while being timed in order to develop a sense of how to pace their activity.

May we use a separate tray to hold ping-pong balls that is not attached to the launcher?


The tray must be checked in as a part of the device during the impound period, and should be marked with the team name and number.

Will there be anything in the inflatable wading pool during the competition to absorb the impact of approaching ping pong balls?

There will be a layer of foam, about 1" thick, which will reduce the likelihood that balls bounce out.  The bottom of the pool will also be inflated.

Do the ping pong balls need to be attached to the launcher somehow when we impound our launcher?

The balls are not required to be attached to the launcher.

They can be contained in a separate bag and must be checked in with the launcher during impound.

The supervisor should be able to verify that only 15 ping pong balls are being impounded.

 In addition, teams might consider other ways to corral the balls during operation to prevent balls from crossing the Launch line by accident.

Can the ball bounce on the floor first before it goes in to the pool or bucket.

Yes, the ping pong balls may bounce on the floor before entering the target area.

Balls are scored based on where they stop, not on how they got there.

Can a tape measure be included with the impounded items and used during the competition?

Only the launcher, marked balls and data log (if they have one).

No separate tools can be brought in.

But- if a range setting aid (like a tape measure or string) is attached to the launcher, it is considered part of the launcher.

What if a tool (screw driver, pliers, wrench) are needed to make modification to the device?

Elements required to operate or adjust the launcher must be physically attached to the launcher in some fashion.

They cannot be loose.

Is there a size limit for the launcher? How wide are the launch lines?

There is no explicit size limit for the launcher.  However, given that students (not parents) must be able to safely move the launcher, that implies a practical limit.

The line width is about 18", but launchers can be wider (or narrower) than that.

If my school has more than one team participating, may they use the same device?

At the Macomb Tournament, no.  Each team that has a separate team number must have their own device.   Two devices from the same school may be very similar in design, but the students who compete are still expected to make their own device.  Every device must be marked with the Team number.  Accordingly, only one Event Team will be allowed to compete with a given device at that tournament.

 At practice tournaments, teams are generally allowed to register more than 16 students, and have “Alternate Team Members” compete.  In these situations, there may be more than one Event Team registered for a given event and team number.  Those multiple event teams may use the device that has their team number.  For more information on participation rules at practice tournaments, see the information published on the Macomb Science Olympiad website, or contact the practice tournament director.

Are safety glasses required to participate in this event?

Yes, as stated in the rules. Side shields (whether clip on or fixed) are preferred.

Are typical household batteries (e.g., AA, C) are allowed in the device?

Household batteries are allowed.  Batteries that contain acid, gases or Lead are not allowed.

Is metal spring acceptable for energy device? What other storage device are valid other than rubber-bands?

Yes, steel springs would be acceptable as well as polymer (plastic) springs.  Compressed air is possible.   Use of electricity (solenoids) might also be possible.  This is unlikely to be a complete list of possibilities.  Whatever the design, it must pass a safety review by the Supervisor.

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Event Supervisor

Rachad Shishakly

Macomb Science Olympiad

P.O. Box 763, Sterling Heights, MI 48311

For questions about the Elementary division, contact This email address is being protected from spambots. You need JavaScript enabled to view it.