There's something very special about science that smells bad and this experiment is no exception. It's time for some kitchen chemistry...here we go!
What do I need:
- Two glasses
- A red cabbage
- Baking powder
- White vinegar
How do I do it?
STEP1 - First the smelly part! Get your red cabbage and chop it up into fairly small (2cm-ish) chunks! Next pop these red cabbage chunks in a pan of water and boil it for a few minutes. You'll know that it's done when the water turns to a deep purple colour. Then strain you cabbage juice and pop it into a bottle!
STEP2 - Now we've got our cabbage juice it's time to get properly started! Fill one glass with white vinegar and the other with water mixed in with a couple of tea spoons of baking powder!
STEP3 - Both of these liquids will be colourless! Now, add your cabbage juice to each of these glasses. You'll see your white vinegar turn pink and your baking soda turn blue!
STEP4 - Just for fun mix the two liquids together!
WARNING: This will make a mess!
What's going on?
Your cabbage juice is what we scientist type people call an indicator. All that means is that it's something that changes colour depending on how acidic or alkali the liquid it's in is! (This is normally measured on a scale, called PH, acids have low PH values and alkalis have higher ones)
Cabbage juice turns red in acids (like your white vinegar) and turns to blue if it's in an alkali or even green if it's in a strong alkali!
The final part is the classic volcano experiment where your acid (vinegar) mixes with your alkali (baking soda) to create bubbles of carbon dioxide and a big mess too!
More Fun Please - Experiment like a real scientist!
- What else can you test to see if it's an acid or an alkali?
- How many different colours can you make with your cabbage juice