Can a rainbow fit inside a glass? Let’s find out! In this colourful experiment, you’ll create beautiful layers and learn all about density as you build your very own rainbow.

YOU WILL NEED:

• Clear Glass
• Food Colour
• Teaspoon
• 5 Paper Cups
• Salt
• Water

DO:

1. Take two tablespoons of water in each of the five cups.

2. Add salt and food coloring to the cups as per below diagram
   

3. Starting with Cup E, slowly pour the water into the clear glass. Using a teaspoon, slowly and carefully add the other cups in this order: E D C B A

WATCH:

The different coloured water doesn’t mix and remains as separate layers because of the different concentrations!

WHY DON’T THE DIFFERENT COLOURS OF WATER MIX WITH EACH OTHER?

THINK ABOUT IT!

When we add the sugar to water it changes the density of the water. The more sugar that is dissolved in the water, the heavier it becomes without causing a change in the amount of liquid, which makes it denser. Cup E, which has the most amount of sugar, is densest and remains at the bottom.

WHY IS IT EASIER TO FLOAT IN THE OCEAN THAN IN A POOL?

LET’S FIND OUT!

The ocean has large amounts of salt dissolved in it, which makes it much denser than the pool. The salty liquid in the ocean holds you up better than the pool water.

Look at that! You’ve made a rainbow in a glass and learned how density works! Great experimenting!