Home > Random Stuff > Make a Lava Lamp

 

By Ruth Barnard


 

Hubble bubble there's no trouble, simply watch the lava bubble… With a few ingredients from your kitchen you can put together a liquid lava lamp experiment. Read on to discover what to do and how it works.

 

     

What you need:

• Baking soda (bicarbonate of soda)

• Water

• Food colouring

• Cooking oil

• Vinegar or lemon juice

• Receptacle of choice: a clear glass, jar or bottle

• A torch

 

What to do:

1. Put 3 or 4 heaped table spoons of baking soda (bicarbonate of soda) into your receptacle.

2. Fill about ¼ of the receptacle with water. Add a few drops of food colouring to your water and stir it with a spoon (you can add this at any stage if you forget to add it like us, just stir it in).

3. Pour cooking oil into your receptacle until it is almost full.

4. Add about a tablespoon of vinegar or lemon juice to the mixture…Watch what happens!

5. Grab a torch to light up your lava lamp experiment and observe the mesmerizing spectacle you have started! You can add more vinegar or baking soda, give it a stir and see what happens.

 


 
     

 
     


Top Tip:

It's great to do this in the afternoon or evening so that as it starts to get dark you can test out your lava lamp and get the full effect of the torch's glow.


 
     

The science behind the magic:

The Chemistry of the Dance

1. When you add oil and water to the receptacle you will notice that the oil sits above the water. This is because the water is more dense than the oil. (Check out our density experiment to learn more about density).

2. When you add vinegar or lemon juice (acid) to the mixture, they are also more dense than the oil. So the acid will sink through the oil and into the water.

3. In the water you have mixed baking soda (base) so when the acid sinks and makes the water acidic you will see an acid-base reaction. The gas bubbles you see are evidence of the carbon dioxide (CO2) produced by the reaction.

4. As carbon dioxide bubbles form they can trap some molecules of coloured water. These bubbles carry globules of water up to the surface and when they pop at the surface the coloured water will sink back down to the bottom.

Experiment

Try this experiment with different quantities, colours or methods. Remember to hypothesise, observe and record your results!

Extra for Experts

The baking soda and vinegar reaction looks great but it doesn't stop at the fizz and bubble there is so much more to learn. Baking soda (sodium bicarbonate) plus vinegar (acetic acid) produces carbon dioxide, water, sodium ion and acetate ion. If this peaks your curiosity you could begin your own research…

 
Happy Experimenting!

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