Ping pong jars

Planning a school fair, looking for some fundraising activities or new ways to keep your young people entertained over the summer? Gratnells Learning Rooms has gone carnival crazy to support good causes and engage the community through fun games and STEM activities.

Learning outcomes

You will be able to:

• Practice your hand eye coordination skills.
• Experiment with the optimal angle, force and bounce height required to improve your success rate and make simple comparisons.

You will need:

• 1 x Gratnells A3 paper (D3) tray
• 1 x Shallow Gratnells (F1) tray
• 25-30 x Recycled glass jars in a variety of sizes
• 4 x Acrylic paint in red, green, blue and yellow
• 4 x Paint brushes (2-3 cm brush width)
• 10-20 x Ping Pong Balls
• 1 x Long table
• 1 x Instruction sheet printable
• A selection of small prizes of your choosing

Preparation:

• Divide the jars in to four equal groups.
• Paint the inside of one of the groups of jars with red paint, one group with green paint, one group with blue paint and the final group with yellow paint.
• Allow the paint to dry and apply a second coat if necessary.
• Arrange the painted jars in the Gratnells A3 paper tray and place the tray at one end of the long table.
• Put all the ping pong balls in the shallow Gratnells tray and place the tray at the opposite end of the same table.
• Print and laminate (optional) the instruction sheet.

What to do:

• Stand at the end of the table with the shallow tray of ping pong balls.
• Throw a ping pong ball towards the jars, the ping pong ball must bounce on the table before it lands in a jar.
• Repeat until all the ping pong balls are gone, modify the angle, force and bounce height required to improve your success rate. Observe the effect of your modifications as you work through all the ping pong balls one at a time.
• 1 point for each ping pong ball in a jar.
• Score 5 or more points to win a prize.
• Write the total number of points next to your team name on the leader board.

What is happening?

This activity is an excellent demonstration of projectile motion. There are several factors (variables) to consider, angle of drop and travel in relation to the table, height of release, speed of travel (velocity) and the bounce. The force of gravity plays its part and there is air resistance to consider too. The physics becomes even more complex if you need to consider an uneven table surface or if you’re working outside and it is windy! All of this combines into the physics of trajectories.

It is possible to consider all these factors and experiment practically without an understanding of complex physics equations. Try altering one thing at a time while keeping the other variables constant, make simple comparisons between the results and enjoy experimenting!

Other things to try…

• Record and analyse your attempts using your device camera and an App such as SloPro, Vernier Physics or VidAnalysis free. Use the Apps to review the flight of the ping pong ball and analyse time and distance. As you experiment with the different variables, record the flight of the ball and analyse the results.
• Share videos of your attempts on social media using #WhatsInMyTray

Health & Safety

As with all Gratnells Learning Rooms What’s In My Tray Activities, you should carry out your own risk assessment prior to undertaking any of the activities or demonstrations.