Lava Lamp Experiment

We’re back with another summer camp science session today. If you missed the introduction I recommend you go back and read it as it includes some general tips for all our science sessions.DIY Lava Lamp Experiment

This week we are going to do a fun experiment which only requires a few simple items. Here’s what you will need:

  • Vegetable oil
  • Water
  • Food colouring
  • Effervescent tables, e.g. Alka Seltzer
  • A large, clean jar or bottle – we used an old plastic juice bottle with the top cut off

Science Experiment Report Sheet

If you want to record your experiment – including your predictions, observations and findings – you can also download a copy of my free ‘Science Experiment Report’ sheet and either print it off or, if you don’t have a printer, use it as a template to create your own. Depending on age, kids can either write and/ or draw their observations.

>>Download Science Experiment Report Sheet

I’ve recorded a video of the experiment, which you will find further down the page. However, I recommend you try the experiment out yourselves first before watching the video, and then you can compare your results with ours.

Safety Tip: Careful when handling food colouring so that you don’t stain clothes or surfaces. Do not let children put any Alka Seltzer tablets in their mouth!

Lava Lamp Experiment

Step 1: Fill your jar or bottle roughly two thirds full of vegetable oil.

Step 2: Mix about 100ml of tap water with a few squirts of food colouring,

QUESTION: What do you think will happen if we pour the water in to the oil? Record your predictions.

Step 3: Carefully pour the water in to the oil. The water will sink to the bottom of the jar/ bottle and sit below the oil. It may take a few moments to settle.

QUESTION: What do you think will happen if we drop an effervescent tablet in to the water-oil mixture?

Step 4: Break an effervescent tablet in half and drop it in.

Once the tablet hits the water and starts to fizz, coloured blobs will rise up through the oil and then sink down again. You can add more pieces of tablet to keep the experiment going.

Here’s a short video from when we did this experiment at home:


The water sinks to the bottom of the jar/ bottle, below the vegetable oil, because it is more dense than the oil. When you drop in the effervescent tablet, it also sinks to the bottom and starts to dissolve in the water as it is water soluble. As the tablet dissolves, it releases carbon dioxide. The carbon dioxide gas rises to to the top of the water-oil mixture, taking blobs of coloured water with it. Once the carbon dioxide gas reaches the top and is released in to the air, the blobs of coloured water sink back down. The cycle will repeat until the tablet is fully dissolved and all the carbon dioxide has been released.

If you enjoyed today’s activity, please feel free to leave a comment or tag me in on Twitter and Instagram. Remember to use the hashtag #BearAndFoxSummerCamp if you are sharing any photos.


All Summer Camp activities are free to make them accessible to as many people as possible. However, if you enjoy the activities and are able to, you can support me with a donation on Ko-fi. Just hit the button below. Every little helps and is much appreciated. Thank you. 

Comments: 3

  • reply
    13 August 2020

    I used to love my lava lamp so this is such a brilliant experiment to do! Bet the kids loved it :-)

  • reply
    15 August 2020

    This is so interesting and fun to do! I will share this with my sister who has a kiddo :)

  • reply
    20 August 2020

    Great Post!!

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