Home Featured Science Experiments for kids : Lemon Suds Eruptions

Science Experiments for kids : Lemon Suds Eruptions

Science Experiments for kids : Lemon Suds Eruptions
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materials needed for the experiment

I set our small containers with clear hand soap and warm water mixed in to create sudsy water. I added few drops of food colors to make the eruptions interesting.. After setting out all the colorful bowls of sudsy water inside a deep sensory tub we usually use for all our sensory activities, I set our baking soda and citric acid.

colored soap water

Please note that you can eliminate citric acid and use lemon juice instead but the size of the foam and eruptions will be less dramatic. Citric acid can be easily purchased online or from the stores. They are usually in the canning aisle. It is a safe, naturally occurring weak acid present in lemons,limes, oranges, tangerines and many more. Here is an affiliate link to purchase the same online.

Next : the kids added scoops of baking soda to each bowl of sudsy water

adding baking soda to colored soap water

Ooh mixing them was so fun. It actually resulted in a fun gooey product.

Now that’s done I surprised the kids by handing over the salt like substance ( instead of our usual vinegar). I told then that we will be adding this to create super foam and fun eruptions.. They couldn’t wait! The kids very eagerly added scoops of citric acid and waited.

add citric acid

As soon as the citric acid/lemon juice hits the baking soda sudsy water combination it immediately creates a very light, airy, fluffy foam which is TOO cool (literally) for words.


The best part of this science experiment : the eruptions are LONG LASTING. I set our small spoons for mixing. The more the kids mixed in the citric acid, the lighter, fluffier and bigger the foam they got.

fizzy foam

Since we ended with paler eruptions, the kids suggested that we add more food colors.

line up pale colored fizzes

The kids added food colors to the sudsy eruptions and most of the time DID NOT match the colors and created multi colored sudsy fizzies.

add more colors

My older was particularly excited with the green and red combination!

mix some more

My toddler creating pink/red eruptions.

add food color to make brighter colors

My toddler loved pretending that they were pink and blue cupcakes and started scooping the foam, very airy foam.

see the sudsy foam

Of course the hands have to go in there, to feel the foam. It was so cold and kids got a big kick out of that chillness of the foam.

colorful science experiment

My toddler making big pink fluffy foam by CONSTANTLY stirring the concoction. The eruptions last long and take a long time to fall flat.

So once we were done making giant foamy eruptions, we HAD TO dig into the fluffy super foam goodness.

sensory rainbow eruptions

The kids dumped the contents inside the sensory tub and created colorful foam.

mix all colors

dump all colors

They went nuts putting their hands through the super foam.

enjoy foam fun

They even brought in their animals for extended pretend play.

play wiht animals

Seriously guys, this one was WAY TOO MUCH fun.

Once I thought they were done we went ahead with the cleaning. What do you think happened there? More play time

What did we actually do in this science experiment? Baking soda is a base and will react with lemon juice (citric acid) releasing carbon- di – oxide as a by-product. The bubbly gas thus released produces the super foam from the hand soap.This is an endothermic reaction which means that during the acid-base reaction heat is absorbed and the super foam is COLD to touch. Such a fun and exciting sensory experience!

Ok that’s not all folks. If you eliminate the colors you will have created a natural, homemade cleaning agent. How cool? Use baking soda, soap and lemon juice/citric acid concoction for cleaning

Recipe for Lemony Sudsy Eruptions:

This “recipe” is pretty forgiving. But if you want a starting point, this is what I used.

  • 1/4 cup clear hand soap
  • 3/4 cup warm water
  • 2 tbsp baking soda
  • 2 tbsp and bit more citric acid

Quick Tip: The more the kids stir the concoction the bigger the foam and the result is all the more dramatic..

Thanks for reading


  1. Wow this looks briiliant; I cant wait to try it. Can you tell me what is in baking soda as we get” baking powder”and “bicarbonate of soda” (which are used for different things) so im wondering which to use.


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