This blog post may contain affiliate links.
Monday, May 25, 2020

How to make a Lava Lamp Experiment Sensory Bottle

Do you want to create all the fun of a lava lamp for your kids without the risk of heat that could burn or glass that can smash? Thankfully it's easy to create a magical lava lamp sensory bottle that's completely safe for kids with this Alka-Seltzer science experiment using four household pantry staples. Follow the tutorial below to make a lava lamp sensory bottle in less than five minutes.

My most favourite thing about my bedroom when I was younger was having a lava lamp. It was so mesmerising watching the oily blobs float up and down. Of course I didn't really have any concept at the time of how dangerous it was due to the heat it emitted. 

Looking back now I can see how much of a hazard lava lamps are, not to mention the huge amount of electricity they require and all of the big fire hazard warnings make me much more nervous now as an adult. 

So, when my daughter found my lava lamp stashed in it's box and begged me to show her, I decided it was the perfect time to do the Alka Seltzer lava lamp experiment I'd been meaning to try for ages. I took it one step further and together we created some lava lamp sensory bottles that she can use over and over again.


The great thing about this lava lamp experiment is that you only need common household ingredients, you probably already have at home. Also the reaction is instant and we all know kids love instant gratification. It can also be kept as a sensory bottle and redone over and over using the same initial bottle.

Supplies needed:

Supplies needed to make an alka seltzer lava lamp

To make a kid safe lava lamp you'll only need four common household supplies: vegetable oil, water, food colouring and Alka-Seltzer tablets. If you're in Australia you may not have heard of Alka-Seltzer tablets as they're not as well known here as they are in America. 

Alka-Seltzer tablets are an antacid and pain reliever combined with three active ingredients: aspirin, sodium bicarbonate and citric acid. When placed in water the tablet quickly dissolves and forms bubbles while reacting with the water {which is what makes them great for this experiment}. In Australia you can buy Alka-Seltzer tablets from Woolworths, Chemist Warehouse and other smaller chemists or online from Amazon AU.

You can create a lava lamp in any clear jar or bottle, I've even seen them done in big wine glasses. If you want to make a sensory bottle that can be used again, I recommend using a plastic bottle with a screw top lid so you can save the mixture to reuse. For ours we used plastic candy jars from Kmart, but they would also work well in plastic Voss water bottles, empty plastic drink bottles or clear sensory bottles you can buy in bulk online


You can make a lava lamp sensory bottle following these four simple steps. Yes it really is that simple

If you follow these steps you'll have a bubbling lava lamp sensory bottle in under 5 minutes. It's so easy to do my 6yr old did steps 3 and 4 by herself. The chemical reaction will last 5-10 minutes, however if you want the lava lamp to erupt again simply add a new Alka-Seltzer tablet to the sensory bottle.

How to do a lava lamp science experiment inside a sensory bottle.


1. Fill your bottle {or jar/glass} 2/3 full with vegetable oil. If you want the lava lamp to be clear you can use baby oil as a substitute.

Pouring water into a lava lamp sensory bottle

2. Pour in water so the bottle is almost full. Make sure you allow some space at the top of the bottle as the chemical reaction will cause gas and bubbling. The water will settle on the bottom under the oil layer.

Lava Lamp Step 3: Add a few drops of food colouring

3. Add in a few drops of food colouring of choice. You can use any colour, however we found that darker colours worked best against the yellow background of the oil. 

Also using squeeze bottle food colouring means children can do this step themselves, however if you only have normal food colouring bottles you could use a pipette.

Child adding alka-seltzer to a lava lamp sensory bottle

4. Add the Alka-Seltzer tablet to the bottle. We found it works better if you slightly crush the tablet in the packet before adding it. Click play on the video below to see the lava lamp come to life with the Alka-Seltzer chemical reaction. 

Please note it is safest to let the reaction occur with the lid off, especially if using a glass bottle due to the pressure created by the gas.


If you're doing this lava lamp experiment with a toddler they obviously won't care about the science behind the chemical reaction that makes the lava blobs occur, however we all know older kids have loads of questions so here's a simple explanation. 

When you initially create your sensory bottle the water and oil layers will split with the oil floating at the top above the water. This is because oil is less dense than water so it rises to the top and the water collects at the bottom. 

When you drop in the food colouring it will fall through the oil layer without mixing and once it reaches the water layer it will mix together to make colourful water. The real fun happens when you drop in the Alka-Seltzer tablet.

Alka-Seltzer tablets are effervescent which means they're water soluble. When the tablet drops to the bottom and hits the water layer the sodium bicarbonate and citric acid react with the water to form carbon dioxide bubbles which shoot up to the top of the bottle in a fizzing motion because gas is lighter than liquid. Once the bubbles reach the top and pop the air is released and the coloured water blobs sink back down to the bottom. The process continues until the entire Alka-Seltzer tablet is completely dissolved.

Blue lava lamp sensory bottle


My 6yr old was still really intrigued by my actual lava lamp after we'd made our own lava lamp sensory bottles so we decided to set up the lava lamp next to the sensory bottle to see the difference between the two. I set it up high on the kitchen bench so the girls couldn't touch it as it got hot. 

It took over an hour to get hot enough to start working properly and in the end we decided the sensory bottle reaction was actually a lot more impressive. So, overall a lava lamp sensory bottle is not only a quicker, easier and safer option for kids, it's also a more impressive eruption of lava than an actual lava lamp.

Lava lamp vs lava lamp sensory bottle


To keep up to date with my latest posts and play activities you can sign up to my email list or follow me on Instagram, Pinterest & Facebook. I'd also love for you to join parents from all around the world in our Facebook community.

Disclosure - This post contains some affiliate links for your convenience which means I may earn a small commission, at no cost to you, should you make a purchase.

Would you like to comment?

  1. Thank you so much. I will definitely try it. The science behind the process is very well explained!

  2. Can you us this over and over or just one day?

    1. Hi Lynn, We used ours for quite a few months before my daughter accidentally knocked it over and the oil leaked. This is why I chose a bottle with a lid so it can be stored when not in use. You just need to drop in another alka seltzer tablet to make it react again.