A Density Column in a Glass

October 04, 2024 / DIY / STEM Activities / Chemistry / Ages 6 - 8 / Rainbow Rain In A Glass

Can you make rain in a bottle? And this rain is rainbow-coloured! Some people also call this experiment underwater fireworks. You can probably tell from the name just how wonderful this experiment is. With simple kitchen materials, you can easily create this at home.

Age: 6-8
Time: Less than 30 minutes
Mess Level: Messy

Materials Needed:

Food colouring
Vegetable oil
Water
Clear glass
Stirring stick

On a light blue surface, against a pale background, the equipment for a Rainbow Rain in a Glass experiment is neatly arranged. A wine glass sits centrally, flanked by two clear plastic cups, one containing water and a small wooden stirrer, the other holding a yellowish liquid (likely oil). Four small bottles of coloured liquid, in red, orange, yellow and blue, are lined up in front of the wine glass. A larger clear plastic jug of water completes the setup. The overall arrangement is clean, organised, and clearly shows the preparation for a science experiment.

Step-by-Step Instructions:

Drop different food colourings into the oil and mix well.

A hand adds coloured liquid from a small bottle to a clear plastic cup containing a yellowish liquid, on a pale blue surface.

A hand gently stirs a yellowish liquid in a clear plastic cup using a small wooden cocktail stick, against a pale blue background.

Fill 3/4 of the clear glass with water.

A clear wine glass, partially filled with water, stands on a pale blue surface against a cream-coloured background.

Pour the oil and food colouring mixture into the water and observe what happens.

A wine glass is partially filled with water, overlaid with a layer of yellow liquid, and streaks of colourful inks create a marbled, rainbow effect.

The Science Behind It:

This involves the principle of density: when the oil mixed with food colouring is poured into the water, the oil, being less dense than water, will float on the surface, encapsulating the food colouring. However, because the food colouring is denser than both oil and water, after a short while, it will begin to sink into the water and dissolve, creating beautiful rainbow rain.

A Density Column in a Glass

Materials Needed:

Step-by-Step Instructions:

The Science Behind It:

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