Try a colorful density experiment with oil, water, and food coloring. You can create fluid interactions using liquids of various densities.
What you will need:
- Several small, clear plastic bottles with caps (remove labels)
- A bottle a vegetable oil and/or baby oil (mineral oil)
- A bottle of 70% and/or 90% rubbing alcohol
- Food coloring
- Optional: Flashlight, funnel, light corn syrup, dish soap
Here’s what to do:
Fill a clear, plastic bottle partway with either water or rubbing alcohol (a funnel may help), and add a dew drops of food coloring. Then, add some of one of the oils and cap the bottle.
Take it further:
- What do you notice when you gently turn the bottle upside down, and then right side up again?
- What happens to the liquids when you vigorously shake the bottle?
- How long does it take for the liquids to mix or separate? A flashlight might help to observe bubble details.
- As your’re concocting bottles with different combinations of liquids, do you notice differences between how water or rubbing alcohol interacts with either oil?
- Does it matter if you use 70% or 90% rubbing alcohol?
- Do the vegetable oil and baby oil behave similarly? Do some combinations yield smaller oil droplets after shaking?
- What do these fluid mixtures remind you of?
- What happens if you try light corn syrup, or dish soap?