Here is a super easy science experiment to reveal a colourful rainbow. This is a great way to have fun with your investigations of bicarbonate soda and vinegar. Plus it is low preparation, cheap and brightly colourful! This activity explores chemical reactions using commonly found house-hold items. You’ll get lots of surprise as the magic of the fizz happens!
How is this a science activity?
This activity explores chemical reactions between the ingredients of bicarbonate soda and vinegar. These are commonly used for at-home science activities as they are readily accessible and create lots of fun.
We have taken this activity a step further by ensuring that we capture and record what we observe. This is always an important step of the scientific process and, here, we have used a method for recording that is age-appropriate for younger children.
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What do I need?
- Ice cube tray
- Bicarbonate soda
- White vinegar
- Food colouring in red, yellow and blue
- Pipette – or you can use a small spoon or hydraulic syringe
- Beaker – or you can use a cup or small bowl
- Coloured pencils
- You will need one of my FREE resources for this activity. These can be accessed using my free resource library. This library is exclusive to my subscribers. Sign up using the form below to gain access. You will need to download the magic rainbow recording sheet for this activity.
How to do it?
Here are the steps to follow:
- Drop 2 drops of food colouring into the sections of the ice cube tray. Use 2 drops of the same colour if you want to make a primary colour (red, yellow, blue) or use 1 drop each of 2 different colours to make a secondary colour (orange, green, purple). We kept the end sections clear of food colouring as we only needed 6 sections for our rainbow.
- Spoon bicarbonate soda into each section of the ice cube tray so that the colour is hidden underneath and it looks just white.
- Place vinegar into the beaker and use the pipette to drop vinegar into a section of the ice cube tray until the colour is revealed. You will get a fizzy solution while the chemical reaction takes place.
- Use the recording sheet from the resource library and colour in the corresponding section with the colour that was found. This is a great way to document your results.
Here is our magic rainbow reveal which we made.
What to do next?
This was such a hit that we had to do it all again! This time, I put any colour in any section as a surprise reveal. The excitement as each colour was revealed was lots of fun and we mapped our results using the recording sheet.
You could easily take this activity a step further and graph your results too. I have a blank graph in my resource library which you can use.
What is the science behind the magic rainbow?
The science in this activity is all in the pH level of the ingredients. Bicarbonate of soda is an alkali while vinegar is an acid. Combining these two ingredients creates a chemical reaction that releases carbon dioxide gas. These are the bubbles that you see and why the mixture makes a fizz.
This is a great way to explore chemical reactions at home. I hope you enjoy making and recording all of your colourful rainbows.