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How to make slime

Slime activity header

In this activity students will discover how a change in the structure of a molecule can change the physical properties. Students will mix PVA (Polyvinyl Acetate) with borax. The borax creates cross links between the PVA molecules. This extends the PVA molecules and result in the new substance having a firmer texture.

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For faster results ask technicians to add the raw ingredients to the cup with astirrer. This allows students to simply stir and observe the changes.

Activity steps
  1. Add 125ml PVA to the beaker.
  2. Add 2 teaspoons of borax.
  3. Mix with a stirrer.
  4. The mixture can become firm and hard, like the texture of fat. If the mixture becomes too thick, add up to two table spoons of water. This will give the desired slime texture, which can be stirred and poured easily.
  5. Add food colouring (optional).
Safety guidance
  • Borax is toxic and should not be consume or touched with bare hands.
  • Ensure students do not ingest mixture and that they wash their hands if they have come in contact.
Guidance for discussion
  • Explain to students that they will be mixing PVA (a polymer) with borax (a smaller molecule).
  • Ask students when doing the practical that they observe changes in the physical properties.
  • Remind students that oil, a liquid, is converted to plastic, a solid. This happens through increasing the chain length through polymerisation. Then ask them to predict what might be happening to the length of the molecules in the PVA and borax mixture.
Expected Results

In this activity students create a polymer. They should observe that by adding borax to PVA the consistency changes. This is analogous to oil changing to plastic, as oil goes from being a liquid to being a solid. Students should recognise that by increasing the length of the molecule in both oil and our PVA-borax mixture we can change their properties.

Ocean plastics sci 11 14 UNIT thumb

Science | Ages 11-14

Ocean Plastics

Ocean Plastics Science ages 11-14 unit is a KS3 teacher resource combining both biology and chemistry. Students discover the journey plastic takes from manufacture, use, and disposal into the ocean. Included are teacher resources that allow students to emulate real research conducted by The University of Plymouth.

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