What you’ll learn: This activity is a great way to learn about properties of oil and water
Water
What you’ll need:
- A glass
- A pencil
- Liquid oil (vegetable, corn, etc.)
- Food colouring
What to do:
- Pour water into a glass (half full, if you’re an optimist!)
- Add liquid oil, and let the two layers separate
- Add several small drops of food colouring to the glass
- Holding the glass at eye level, look at the underside of the oil’s surface – there are your floating spheres!
- Using a pencil, push the colour balls down into the water and watch what happens
After you’ve completed the activity:
- Discuss what happened. Why do you think the water and oil didn’t mix?
- Explain that water is made up of millions of tiny molecules with a positive charge at one end a
- nd a negative charge at the other (called ‘polar molecules’). Water ‘sticks together’ because the positive charge at one end of a molecule attracts the negative end of the next molecule, forming a strong chain. However, molecules that make up oils are ‘nonpolar’, so water molecules aren’t attracted to it.
