Free STEM Lessons: Making a Milk Rainbow

I love doing this experiment with my students. I have made Milk Fireworks, Milk Explosions, Milk rainbows or what ever you wish to call them for years in my classrooms. Children love to experiment and learn and encouraging them to question the world around them is one of the greatest things a teacher can do.

Making a milk rainbow or milk firework simply requires a few drops of food coloring placed in milk and a drop of soap added to initiate the chemical reaction between them. It is beneficial to use oil based food coloring, washing liquid and full fat milk to achieve the most dramatic results.

I enjoy putting real activities and learning experiences into my classes and this is great for it. 

I don’t think English learning just has to be about textbooks and teacher led lessons so using these activities the students not only learn simple science techniques and vocabulary but they also get to practice their English is an authentic , fun and engaging setting. 

So i have, and am continuing to use, these science experiments in ESL classrooms to let the students enjoy using a second language for real and not just for practice!

I have included the instructions and some simple tasks for students to follow to do this classic experiment at the bottom of this post. It is free to download.

Their reaction is great and it really sparks their curiosity. It can be used to teach colors and procedural text for grades 3 plus. Is also part of the upcoming full ESL science pack that has many lessons, vocab and oral matching or description activities and suggestions for home activities for further learning. 

Instructions:

This experiment is so easy you can do it at home (ask your parents first!) you are going to make a rainbow with some milk and some food color. It really will be amazing and you will want to do it again and again!

Equipment ( things you need)

• Plastic plate for the milk
• Old Newspaper incase of spills!
• Soap
• Cotton buds
• Full Fat Milk
• A selection of Food Colorings ( this is important as there are different types. We use these as they are 9 Dollars for 12 on Amazon! Link under here 🙂
• A camera or paper
• The worksheets and activities for free download!

Method ( you can look at the photo to guide you for this as well.)

1. Put some milk onto the plate just so the bottom of the plate is covered. Full fat is better than no fat milk but you can try this as well later to see what happens. Make sure there is some old newspaper in case of spills!

1. Carefully drop 2 or 3 drops of your food color into different parts of the milk. Do not use too much. Try different colors in different places.

Before you do the experiment:

Can you write down or draw what you think you will see when you put the soap into the milk? What do you think will happen?

3. Now you are ready to try to make your rainbow. So put a little drop of soap on to your chopstick or cotton bud.

4. Now put the soap slowly into the milk and watch what happens. You can try to put it in other parts of the milks to see what it looks like.

5. This is your milk rainbow, and it will look fantastic! Now it is your turn to do a little bit of work.

Explanations

This is a sure fire hit with students, and if you are homeschooling you can do it at home as well. As this is a science experiment it would be useful to know the science behind it as well! Now i teach second language learners, so I am a little more basic than the following explanation.

We also have a YouTube Video that guides you through this popular experiment below.

Milk, or the fat inside the milk is a non polar molecule, simply put it doesn’t dissolve in water (you can see this in a frying pan when you try to clean it. The fat floats to the top.) When soap is placed into the mix the soap breaks up and collects the fat molecules. As they chase the fat molecules about in the milk they disturb the food coloring, which means we can see all this movement, and as a by product we get beautiful patterns emerging!

If you want the full on science reasons why this happens, this guy knows what he is taking about.

I explain it that the soap chases the milk fat around and the food colouring gets bumped all over the place. My students are seven and way more interested in having another go!

Here is the link to the download page

Hope you enjoy the lesson, please comment if you did 🙂

Hi I’m Marc. A teacher of over 15 years, English, General Studies and Outdoor Education. Thought it was about time to sharing both what I have learnt during that time and the resources I have put together. On this site we aim to teach the theory and share our thoughts, but also go that one step further and give you access to the hard resources you need for your class or for you children