Science question: What’s soft like a liquid but holds together like a solid? In this experiment, you will make an easy slime recipe and explore its colloidal properties.
Supplies needed:
• Bowl • Liquid starch • White glue • Liquid watercolour paint or food colouring
The experiment: In a bowl, combine equal parts of starch, glue and paint or food colouring. Use your hands to mix it up. The key to making good slime is mixing it really, really well. If after a lot of mixing, the slime hasn’t formed well, add a small amount of glue and mix some more. If it’s still not forming, add a small amount of the liquid starch.
The outcome: When you use your hands to combine the ingredients, it forms a solid, starchy blob.
Why it worked: Slime is a colloid, or substance that is evenly dispersed through another substance. Your slime has the characteristics of both a solid and a liquid. It moves more slowly than water, yet it is wet, and it slides quickly.
Variation: What do you think would happen if you added more starch to the mix? How about more glue? How would the slime feel and act differently?
Did you know? Different types of fluids flow at different rates. This is called their viscosity. For instance, ketchup is much more viscous that water. Slime has an interesting property in that its viscosity isn’t always the same. It can change; such as if you add stress. This type of fluid is called a non-Newtonian fluid, and other examples are ketchup, yoghurt and mud. Safety first! Don’t taste the slime!
Source: The 101 Coolest Simple Science Experiments by Rachel Miller, Holly Homer & Jamie Harrington.