Racing rainbow science activity

**Post updated 6th April 2020

This is a really fun science activity for kids. It’s easy, cheap, has minimal preparation time and produces very colourful rainbows! Lolly rainbows are always a big crowd pleasure with kids and I have turned this concept into a scientific study. The ‘racing rainbow game’ determines which type of food produces the completed rainbow the quickest. On your marks, get set, GO….

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For educators/teachers

If you are an educator and/or teacher I have a resource for doing this scientific inquiry with your students. It contains all of the recording sheets you need to complete this activity with an aim, materials, methods, results, discussion and conclusion. It also has 3 different difficultly levels to suit what you need to teach. Plus I have included a completed example, marking suggestions, student learning outcomes and specific teaching notes for this activity.

How is this a science activity?

This example pitches 3 different types of lollies against each other in a race against time. We are trying to answer the question of “which lolly will complete a rainbow the quickest”. The lolly becomes the item that we are changing in each test run (known as the independent variable) and the time that it takes to complete the rainbow is what we are observing (the dependent variable). All other aspects such as the type of plate, amount of water and the technology used to keep time are kept the same (known as the control variables). This experiment also incorporates mathematics as we need to determine and record the time for the rainbows to form and technology in the form of a stopwatch.

What do I need?

Smarties
Skittles
MnMs
3 x Plates preferably with a rim or a slope towards the middle to form a guide for the circle.
Stopwatch. You can use this on your phone, but I prefer giving the kids a tactile item to record time. It is more of a novelty and they love being able to control the buttons.
Water

How to do it?

Here are the steps to follow:

Using one type of lolly per plate, arrange the different lollies in a circle on each of the plates.
Gently pour water into the center of each circle until it reaches the lollies
Start the stopwatch
Watch as the colours from the lollies start to move into the water and form a rainbow
When a full rainbow is formed (with no remaining white plate visible in the centre) record the time on the stopwatch
Compare the results you have obtained and determine the winner of the fastest to form a rainbow

Results

Here are our results for our experiment:

Lolly Type	Time Taken (mins)
Smarties	2.32
Skittles	3.47
MnMs	5.18

The SMARTIES were the winner for our experiment!

Bonus Rainbow

We had lots of lollies left over so we decided to make the ULTIMATE rainbow with them. We placed one of each of the 3 different lollies alternating around the circle. That is, a smartie followed by an MnM and then a skittle. This pattern is then repeated. Here is the resulting rainbow!

What is the science behind the rainbow?

These lollies are coated with a coloured sugar layer on the outside. When it comes into contact with the water it dissolves quickly. The outer shell of each lolly will dissolve at the same rate meaning that the colours don’t mix together. That is, unless you bump the plate!

Conclusion

This is a super simple science activity that you can do at home. It is quick, hands-on and best of all creates a fun colour pattern to watch.