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Description

Explore the science behind slime by cooking up a batch of your own.

Courtesy of The Scout Association
https://www.scouts.org.uk/activities/slimy-states/

Resources

Spoons
Kitchen scales
Mixing bowls
Measuring jugs
Food colouring
Cornflour

See video for more guidance at scouts.org.uk/activities/slimy-states/

Safety; Science
Supervise young people, and only do science activities that are advised and age appropriate for your section. Test activities first, to make sure you’re confident you can lead them safely. Use protective clothing where necessary.

Adaptions for running this online
- Plan ahead and let everyone know what equipment they’ll need to do this activity online at home. You could think about safely delivering the equipment to group members if it’d be appropriate and manageable for your group.
- Check out the advice on using Zoom and other popular digital platforms and the guidance on being safe online at scouts.org.uk

Take it further
Watch how non-Newtonian fluids react to a vibrating surface by wrapping a speaker in cling film and placing the mixture on top. Play different types of music at varying volumes, and see how your slime reacts.

Instructions

Liquids or solids?
- Everyone should think about what makes something a solid, a liquid or a gas. We call these ‘states’. What properties does each state have? How can you tell which state a material is in? One way is by looking at the shape it makes: solids have a fixed shape, while liquids take on the shape of the container they are in. How many solids, liquids and gases can you name?

- Everyone should think about slime. Is it a liquid or a solid? Think about the characteristics that show it could be either.


The slime experiment
1. Everyone should split into small groups or pairs.

2. Using scales, put 250g of cornflour into a mixing bowl.

3. Everyone can choose the colour of their slime by adding a couple of drops of food colouring to the cornflour.

4. Measure out 250ml of water and slowly pour 150ml into the cornflour, stirring the whole time. Make sure the water is completely mixed into the cornflour, with no dry areas left.

5. The mixture needs to be the consistency of honey. If it’s not there yet, keep pouring in water and mixing. You may not need all of the water so make sure you don’t add too much.


Decide on the state
1. Everyone should play with their slime to test which state of matter it is: liquid or solid. Does it feel like other liquids or solids when you touch it? Does it change or hold its shape? Can you pick it up and make it into a shape? What happens to that shape when you stop touching it?

2. Everyone should discuss the way that slime seems to have properties similar to both liquids and solids. This is called a non-Newtonian fluid, named after Sir Isaac Newton, who developed a law that classified liquids by how fast they flow.

[Liquids like water flow fast out of a tap; we call this a normal or Newtonian fluid. What would happen if you put slime in a tap and turned it on? Would it come out like water? Slime is a non-Newtonian fluid because it behaves like either a liquid or a solid depending on how much pressure you apply to it. When you poke and roll the slime, it holds its shape under the pressure of your hands. If you leave the slime untouched, it acts like a liquid because it isn’t under any pressure.
Everyone should return to their slime and test it under different pressures, to see how it behaves like both a solid and a liquid. Lots of pressure makes the particles within it lock together and makes it solid. Little pressure makes the particles within it flow over each other, keeping it floppy and liquid.]



Change the level of challenge
Make a giant batch of slime with the whole group and see if you can walk across it without sinking. Watch how non-Newtonian fluids react to a vibrating surface by wrapping a speaker in cling film and placing the mixture on top. Play different types of music at varying volumes, and see how the slime reacts.

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