CPD Workshops

Go slow

by Fellowship Agency August 13, 2018

This activity was created as part of a Gratnells What’s In My Tray CPD workshop for secondary science technicians to support practical work and delivery of the curriculum. It can be carried out as a stand-alone activity for students or combined with other activities from the session to form a STEM carousel.


Go Slow! – STEM Challenge

You will need (per team of 4):

  • 1 x Shallow Gratnells (F1) tray with lid
  • 1 x Gratnells art tray
  • 2 x Sharp scissors
  • 20 x Bendy plastic straws
  • 20 x Jumbo art straws
  • 2 x Washi tape 5m roll
  • 1 x Blu tac pack
  • 2 x Cardboard tubes
  • 4 x A4 coloured paper
  • 2 x A4 coloured card
  • 2 x squares bubble wrap 5x5cm
  • 1 x Stopwatch
  • 1 x Small glass marble
  • Small start and finish labels (printable available to download)

Tip: if you are running this activity as a team challenge, use different coloured trays, paper, card and straws for each team.

This activity also works as an individual challenge, just increase the amount of time allocated to complete it.


  • Print the start and finish labels. Cut them out (one set per team). Laminate and cut out (optional).
  • Blu-tac the start and finish labels to the bottom of the art tray in the top left and bottom right-hand corners respectively.
  • Place all the other equipment into the shallow Gratnells (F1) tray and put the lid on.

What to do:

  • Use any or all of the contents of the shallow Gratnells tray to make a marble run inside the large art tray.
  • Prop the large art tray up on the edge of the shallow tray to ensure the art tray is tilted at the right angle. Tip: Use blu-tac to stop the trays from slipping if needed.
  • The marble must start at the start marker and end at the finish marker, what happens in between is entirely up to you!
  • The aim is for the marble to travel as slowly as possible between the start and the finish.
  • The winning team will be the one whose marble takes the longest to reach the finish.
  • Your marble should not be stationary for any longer than 1 second during the run and, once released, you should not touch your marble again until it reaches the end.
  • When you have finished, or at the end of the allotted time, put your marble run aside until everyone has completed the activity, we will test all the marble runs simultaneously at the end.

When all participants/teams have completed the activity, conduct the timed marble runs and see which run was the most effective at slowing the marble down. Allocate points to each team.

What is happening?

Can you beat gravity? Gravity is the force that ‘pushes’ everything to the ground. Gravity acts on your marble and sends it straight down from the top to the bottom of your tray when you release it. You need to be as creative as possible in trying to slow your marble down and defy gravity. Use what you know about friction and gravity to help you. The equipment can be used to create slopes at different angles for your marble to run along. The shallower the angle the slower your marble will travel because the effect of gravity will be less. Use other items in the shallow tray to introduce more friction. The more friction there is between the marble and the surface it is rolling over, the slower it will travel. Rough or bumpy materials generate the most friction, for example, the bubble wrap or cardboard tube generate more friction than smooth plastic straws.

Other things to try…

  • After you have completed the first timed tests of your marble run, modify and change it to slow your marble down even more. What could you do to your equipment to introduce more friction?
  • Compare your marble run to those designed by other teams or individuals, which ideas were the most effective?
  • Can you extend your marble run to additional trays or over other surfaces?
  • Film your marble run from different angles and use editing software to create a marble run movie. Share your movie via social media using #WhatsInMyTray.

For more images and videos of this activity taken at the National Technicians Conference in York see here.

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.