You will need:
- A kettle
- Either a ceramic mug or a heatproof glass (we used a glass to show the colour change clearly)
- Lemon
- Teabag
- Knife
- Chopping board
- Adult help!
The lemon juice and tea colour change is subtle but it works!
Ask an adult to cut a lemon in half.
Ask an adult to boil a kettle and then add the hot water to tea bags in a mug or heatproof glass. You may want to choose a white mug to see the contrast in the colour change.
Allow the teabag to sit in the hot water for a minute or so and then take it out. As an option you could setup a camera to take a photo of the water’s colour for reference of the colour change later.
Squeeze a few drops of lemon juice into the glass and watch the colour carefully (again, if you use a white mug you will have a good background to see the colour change more easily)
You should have seen the tea go a lighter shade of brown! If you had a setup a camera prior, take another photo and then use a service like Adobe Photoshop or an app such as pixel picker to compare the hex codes to get a fair result without bias.
Try squeezing even more lemon into the tea! In this photo we squeezed several lemons into tea and we found the tea go a much lighter colour.
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What is going on?
Black tea contains pigment called thearubigins. These are typically a red/brown colour in water, however if the water is acidic the pigment changes to a much lighter colour. Lemon juice is acidic and by adding some drops of lemon you quickly change the pigments in the tea! These pigments also become much darker in alkaline conditions.
You can also make your own indicator using cabbage juice too! We used this recently as an example of modelling how a pandemic spreads in a classroom.
Variable to test
- What happens if you use more than 1 teabag?
- Do limes, grapefruit and other citrus fruits produce the same effect?
- What if you use apple juice or other juices?
- Try soft vs hard water
- Try different teabags from different companies.
- Try green tea vs black tea
From colour changes to slimy science, we’ve got your kitchen chemistry covered!
Get in touch with FizzicsEd to find out how we can work with your class.
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i just found out that more lemon juice you put more go clear the colour and if u put less lemon is go dark so cool and i love esperiment
Awesome!
kk,, good info
Oh wow, this is great to hear and know! We’re glad that you found out site and we hope it was useful 🙂