CPD Workshops

Secondary squishy circuits

by Fellowship Agency January 9, 2019

This activity was created as part of a Gratnells What’s In My Tray CPD workshop for secondary science teachers and 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.

You will need (per team of 4):

  • 1 x Gratnells shallow (F1) tray with lid
  • 2 x Gratnells mini trays or one 4 section tray insert (optional, for organising equipment)
  • 1 x Ball of insulating dough
  • 1 x Ball of conductive dough
  • 1 x 9V PP9 battery
  • 5 x Different coloured LEDs (plus a few spares kept to one side)
  • 2 x Electrical circuit wires with crocodile clips at each end (often black and red but don’t need to be)

For preparation (per workshop):

  • 1 x Microwaveable container with lid
  • 2 x Large resealable food storage bags
  • 1 x Wooden spoon
  • The dough ingredients (see here)

This activity also works for individuals or smaller teams, just increase the amount of time allocated to complete it.

This activity can be repeated multiple times, reusing the same equipment for each team.


  • The method for making the two doughs can be found here. Use food colouring in the conductive dough to ensure the two doughs are distinct and reduce the risk of mixing them during use.
  • Place the doughs, battery, LED’s and electrical wires into the shallow Gratnells (F1) tray. Use the mini trays or a tray insert to help keep the wires and LEDs tidy and organised.

What to do:

  • Approach the tray and lift the lid.
  • Use the equipment in the tray to light up as may LEDs as you can.
  • You must use the dough.
  • Do not connect an LED directly to the battery using the wires/clips, this will damage the LED and you will no longer be able to achieve the maximum points for the activity.
  • HINT: the long leg of the LED is positive.
  • Take a picture to evidence your success.
  • 1 point per LED on simultaneously. 5 points available in total.

Tidy up time:

  • Take your circuit apart.
  • Separate the doughs carefully to ensure they don’t mix.
  • Place the doughs back in their respective bags, place all the equipment back in the tray, leaving it just as you found it, and replace the lid.

What is happening?

For a simple way to construct a squishy circuit take a look at our video.

An explanation of what is happening, further activities and questions can be found with the video.

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. In particular, participants should be advised not to connect a LED directly to the battery using the wires/clips as it will ‘pop’, the LEDs should only be connected via the dough.