Rainbow in a Jar

Have you ever wondered why liquids can stack on top of each other without mixing? In this exciting hands-on science experiment, students discover the magic of density — one of the most important concepts in physical science!

Using just water, salt, and food colouring, young scientists create a stunning six-layered rainbow inside a jar. Each colourful layer stays perfectly in place because of the amount of salt dissolved in it — the saltier the water, the heavier and denser it becomes, causing it to sink below the lighter layers.

This experiment makes an invisible science concept beautifully visible — and unforgettable.

What students will discover:

• What density means and how it affects liquids
• Why some liquids float and others sink
• How to follow a scientific procedure step by step
• How to observe, predict, and explain results like a real scientist

Suitable for: Grades 3 to 6 Duration: 20 to 30 minutes Materials needed: Water, salt, food colouring, cups, a spoon, and a clear jar

No lab required — just curiosity, a kitchen, and a love for colourful science!