Slime is super exciting to make but also demonstrates some crazy science. Why not try to make this gooey wonder?
Plan
Where will you make your slime?
Who do you need to help you?
What materials do you need?
What do you need to make you're safe during this experiment?
Do
What happens if you stir fast or slow? Is there a difference?
(for Older Scouts) How would you explain the science to a younger Scout?
How will you store the slime?
Review
What did you enjoy about this experiment?
What other non-Newtonian fluids can you find?
WHAT YOU NEED
- 1/2 teaspoon borax (available at supermarkets)
- 1 cup PVA glue
- 1 cup water
- 1 cup warm water
- plastic teaspoon
- medium size mixing bowl
- measuring jug
- rubber gloves
- food colouring
- decorations eg. glitter (optional)
- plastic snap-lock bag/container
WHAT TO DO
Safety: Younger Scouts should only make slime under Adult Supervision. Rubber gloves should be worn when handling borax as it is a poisonous, corrosive chemical. Read the safety instructions on the borax container before proceeding.
- Put on the rubber gloves.
- Carefully add the borax to 1 cup warm water and stir well with the teaspoon until the borax has dissolved.
- In a bowl place 1 cup water and 1 cup PVA glue. Add food colouring and decorations of your choice. mix together well.
- Add borax water to the glue/water mixture and stir well. You slime is ready when it becomes thick (as shown in the video above)
- Experiment and play with your slime. Observe what happens when you stretch the slime slowly. Observe what happens when you stretch the slime quickly.
- When finished, store the slime in a snap-lock bag. (The food colouring in the slime will stain any surface it’s left on. The slime will keep for a couple of weeks before becoming mouldy.)
Make sure to wash your hands thoroughly after playing with your slime even if you've been wearing gloves.
WHAT'S HAPPENING?
Polyvinyl alcohol found in PVA glue is a polymer. The word polymer comes from Greek ‘poly’ (meaning ‘many’) and ‘merus’ (meaning ‘parts’). Polymers are made up of many small molecules (monomers) joined by chemical bonds to form long chains. These chains are flexible, allowing the polyvinyl alcohol to flow in a disgustingly, slimy manner.
This polymer slime is a fluid but it doesn’t flow normally, so it is a special type of fluid, called a non-Newtonian fluid. Other examples of non-Newtonian fluids are cornflour with water, blood, shampoo and paint. When this polymer slime is pulled slowly, it becomes thin and flows easily. Pulling the slime quickly makes it thicker and it can snap because the chemical bonds in the slime break. The chemical bonds in this polymer slime stretch before they break. This makes the slime elastic (stretchy) which allows it to bounce.
When borax and polyvinyl alcohol are combined they undergo a chemical reaction. We can observe the chemical reaction by feeling the mixture becoming cold. Therefore the chemical reaction is an endothermic reaction, meaning it absorbs heat energy. (An exothermic reaction is the opposite, it releases heat). Borax forms cross-links between the polymer chains in the polyvinyl alcohol. These are chemical bonds that hold the chains together, making the mixture less flexible and much thicker.
DID YOU KNOW?
The plastics we use daily are made of polymers and so is our DNA. DNA is a biopolymer (ie. a biological polymer) and is made up of individual base pairs of arginine, cytosine, guanine or thymine. Teflon, which is used in non-stick pots and pans, and Kevlar, which is used in bullet-proof vests are also examples of polymers.
