# Lemon Suds Eruptions
> Add baking soda and citric acid to bowls of colored soapy water to make long-lasting, cold, fluffy foam eruptions. A vinegar-free science experiment that turns into sensory play.
- URL: https://www.funlittles.com/science-experiments-kids-lemon-suds-eruptions/
- Ages: 2–7 yrs · Difficulty: easy · Mess: high
- Time: prep 10 min, activity 30 min
- Works for: one-on-one, small group, whole class · one batch serves about 2 kids
- Skills: science, acid-base-reactions, color-mixing, sensory, fine-motor
- Cautions: citrus, food-dye, ingestion-risk

## Materials (one batch)
- 0.25 cup Clear hand soap (household)
- 0.75 cup Warm water (household)
- 2 tbsp Baking soda (household)
- 2 tbsp Citric acid
- Food coloring
- Small bowls (household)
- 1 piece Small spoons (household)
- 1 piece Deep sensory tub
- Toy animals (optional) (household)

## Substitutions
- Instead of citric acid: Lemon juice (Works, but the foam and eruptions will be less dramatic.)

## Safety
- Citric acid stings eyes and cuts — use small amounts, keep hands away from eyes, and wash hands after.
- Soapy foam is not for eating; supervise toddlers closely.
- Rinse hands well afterward; a reader warns that citrus juice on skin plus sunlight can cause skin burns.

## Steps
1. Mix clear hand soap and warm water in small bowls.
2. Add a few drops of food color to each bowl.
3. Set the bowls inside a deep sensory tub.
4. Add scoops of baking soda to each bowl and mix.
5. Add scoops of citric acid and watch the foam rise.
6. Stir and stir — the more you mix, the bigger the foam.
7. Add more food colors to brighten the foam.
8. Dump all the bowls into the tub and feel the cold foam.

## Tips
- The more the kids stir the concoction, the bigger the foam and the more dramatic the result.
- The eruptions are long lasting and take a long time to fall flat, so there's plenty of time to play.
- The foam is cold to touch — kids got a big kick out of the chillness.
- Bring in toy animals for extended pretend play.
- This "recipe" is pretty forgiving — use the amounts as a starting point.
- Soap and lemon juice makes a ton of foam. (from readers)

## FAQ
**Should I use baking soda or baking powder?** Baking soda — it's bicarbonate of soda.
**Which makes more foam, vinegar or citric acid?** The author says soap with lemon juice makes a ton of foam; the post notes citric acid gives bigger foam than lemon juice.
**Is this really a science experiment?** Yes. It's a simple acid-base reaction (citric acid + sodium bicarbonate) that releases carbon dioxide, which whips the soap into foam. It's endothermic, so the foam feels cold.

## The original post by TurkeyMom (2013)

One of the best ways to inculcate a love for science in kids is by doing [**hands on activities.**](https://www.funlittles.com/category/science-2/) In this case we are doing a fun hands on science experiment that has so many aspects built into it that this turned into one of the most enriching and stimulating activities we have ever done. This one science experiment is a learning activity, sensory activity, fine motor activity all rolled into one. To top it all at the end of the science experiment you will have created a homemade all natural cleaning agent! How cool is that? We have done a few science experiments in the past, our recent [**red cabbage experiment**](https://www.funlittles.com/science-experiments-kids-scientist-dramatic-play/) and a similar [**baking soda and vinegar activity**](https://www.funlittles.com/science-experiments-for-kids-color-mixing-kids-activities/) . Today we share another recipe for the same fun colorful explosions by switching the acid. We are again showing a **vinegar free science experiment** The supplies you will need.

 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](https://www.funlittles.com/category/sensory-bins/),** I set our baking soda and citric acid.

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

 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.

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

 My older was particularly excited with the green and red combination!  My toddler creating pink/red eruptions.  My toddler loved pretending that they were pink and blue cupcakes and started scooping the foam, very airy 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.**

 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.

 The kids dumped the contents inside the sensory tub and created colorful foam.   They went nuts putting their hands through the super foam.

 They even brought in their animals for extended pretend play.

 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**