Disappearing color sounds a little like magic, for your kids, especially if they are young, it will probably be magic. This is one of the easiest science activities you can do at home. It is a bit like magic, this chemical reaction between two things. We love science experiments like this.
Disappearing Color Science Experiment
You only need 3 things: water, food color, and bleach.
If you have ever cleaned with bleach you know just what it does, it bleaches, it removes color. Just ask the t-shirt I was wearing the other cleaning my bathroom, thankfully I was smart enough to change out of my new black sweater.
What you need:
- a jar
- water
- food color
- bleach
How to do a Color Changing Experiment
Simply fill a clear container, a jar in my case, with water. I did use water from our reverse osmosis tap, it was out of habit, regular tap water works just fine as well.
Add some food color, stir it if you’d like, but it is not necessary.
Grab some bleach, I used an old dropper to avoid spilling, or water and bleach splashing back out. Add a bit of bleach to your colored water.
We added a tablespoon of bleach to start and added a tablespoon at a time as we went.
A tablespoon of bleach was added to our jar and after a few minutes, the bottom half of our jar was colorless.
Or the color of the bleach, you can see that there is a hint of yellow. Add more and see what happens, maybe give it a little stir.
Be careful. Parental supervision is a must.
I can’t stress how careful you and your kids need to be. Bleach on the skin can be painful, and in the eyes horrible.
Also once you have bleached the color of something there is no getting it back, so we don’t want to have a spill.
Maybe take this outside to avoid it getting spilled in the house.
It’s cool to watch, but what’s really happening?
What’s Happening:
Bleach contains an oxidizer. It reacts with the color molecules in food coloring. Although the pigment molecule remains, its shape changes so that it can’t absorb/reflect light the same way, so it loses its color as a result of the chemical reaction.
Try It:
Try adding some more food color into your jar now that all the color has disappeared. It won’t react the same way it did in the beginning.
Disappearing Color Experiment
Science Experiment using colored water and bleach.
Materials
- Bleach
- Water
Tools
- Food color
- Jar
Instructions
- Simply fill a clear container, a jar in my case, with water. I did use water from our reverse osmosis tap, it was out of habit, regular tap water works just fine as well. Add some food color, stir it if you'd like.
- Grab some bleach, I used an old dropper to avoid spilling, and add a bit to your colored water. We added a tablespoon of bleach to start, and added a tablespoon at a time as we went.
- A tablespoon of bleach was added into our jar and after a few minutes the bottom half of our jar was colorless. Or the color of the bleach, you can see that there is a hint of yellow. Add more and see what happens, maybe give it a little stir.
Notes
What is Happening:
Bleach contains an oxidizer. It reacts with the color molecules in food coloring. Although the pigment molecule remains, its shape changes so that it can't absorb/reflect light the same way, so it loses its color as a result of the chemical reaction.
Resources for this activity
Disappearing Color Experiment Variations for Kids
This simple activity—mixing colored water with bleach to make the color vanish—is one of those classic science experiments for kids that feels like magic. If you want to take it further and make it an even more valuable part of your homeschool science activities, try these fun variations and extensions. They’ll keep kids engaged while also reinforcing real scientific thinking.
Variations to Try
-
Test Different Colors Side-by-Side
Set up several cups with different food coloring (red, blue, green, yellow). Add the same amount of bleach to each and see which one disappears fastest. Kids will love comparing how each pigment reacts. -
Use Different Types of Water
Try the disappearing color experiment with tap water, distilled water, or even well water. This helps kids notice how minerals in the water may affect the reaction. -
Compare Bleach Strengths
If you have different types of bleach (regular, concentrated, or scented), test them to see which works faster. It’s a safe way to show how chemical concentration changes reaction speed.
Ways to Extend the Experiment
-
Track the Reaction Over Time
Use a timer and record how long each color takes to disappear. Kids can write notes or take pictures to practice observation skills. -
Measure Temperature Changes
Place a thermometer in the cup to check whether the reaction causes a slight rise or fall in temperature. This introduces ideas like exothermic reactions. -
Add Fresh Drops of Color
Once the solution has turned clear, add another drop of food coloring. Watch how quickly it fades when bleach is already in the mix—kids will be fascinated! -
Apply It to Fabric
Drip the solution onto small fabric scraps to see how bleach removes dye from cloth. This creates a real-world connection to laundry and stain removal. -
Discuss the Chemistry
Explain that bleach works as an oxidizer, changing the dye so it no longer reflects visible light. This is a simple way to introduce redox reactions to kids.
Taking It a Step Further
-
Connect to Other Color-Changing Experiments
Once your kids enjoy this project, introduce them to similar hands-on science for kids activities like the Chemical Chameleon experiment or the Blue Bottle experiment, both of which involve amazing color changes. -
Make Predictions First
Before starting, have kids guess which color will disappear first, or which type of water will work best. Afterwards, compare results to their predictions—this builds critical thinking. -
Create a Controlled Experiment
Guide older children in setting up a true experiment with variables. For example:- Does adding more food coloring slow down the bleach reaction?
- How does stirring change the speed of color disappearance?
- Will a small drop of bleach work differently than a large amount?
-
Environmental Reflection
Use the experiment as a springboard for talking about safety. Discuss what happens if bleach goes into rivers or lakes and why proper disposal matters.
Summary of Extensions
| Extension Type | What Kids Learn |
|---|---|
| Color & Water Variations | Compare pigment behavior and how minerals affect reactions |
| Timed Reactions | Practice recording data and developing observation skills |
| Adding New Drops | Explore how reactions change in already-altered solutions |
| Fabric Testing | Connect science to everyday life with fabric and laundry |
| Chemistry Connection | Introduce the basics of redox and oxidation reactions |
| Prediction & Hypothesis | Teach critical thinking and the scientific method |
| Environmental Awareness | Encourage responsible use and disposal of household chemicals |
By trying these disappearing color experiment variations, you can turn a short activity into a complete science lesson. It’s fun, hands-on, and a perfect fit for kids of all ages—whether you’re homeschooling or just looking for easy science experiments for kids at home.