Easy Test Tube Science Experiments for Kids


I love teaching science and preparing science experiments for kids. One thing I try to do is introduce children to real science equipment and tools, like test tubes, microscopes, and eye droppers. This test tube experiment makes kids feel like real scientists.

When I first show them the tools, they are excited and often tell me that they have seen the equipment before – either on t.v. or pictures, but given the opportunity to get their hands on it and use it is incredibly meaningful.

Plus, children’s excitement of being a real scientist always makes it worthwhile. Since I teach kindergarten, I need easy science experiments for kids.

This experiment was a hit with my students, and one of my all time favorites.

As with all science experiments, make sure to have an adult supervise at all time. Make sure all materials are age appropriate for the children doing the experiment.

science experiments for kids


I teach kindergarten prep, so I did this experiment with over 100, 3-6 year olds. You will need several materials, but many are materials you may already have on hand.

  • Eye Droppers
  • Red Food Colouring
  • Oil
  • Dish Soap
  • Corn syrup
  • Test Tubes or Other Thin Container

If you don’t have access to test tubes, clear cups or containers work just as well!

To start, you will need corn syrup with blue food colouring added to it. Green dish soap, water with red food colouring and oil. You don’t have to use the same colours that I did, but a rainbow of colours looks best.

science experiments for kids
Materials for Kindergarten

Science Experiments for Kids Steps

I added the corn syrup to the test tube ahead of time only because it is too thick to add with the eye droppers.

Once the corn syrup is on the bottom, carefully add the dish soap. I found it easiest if you let the liquid slide down the side of the test tube.

It is important to add the liquids slowly so that they sit on top of the layer below. As long as your don’t squirt the liquid in, it will work.

science experiments for kids

Next, add a layer of water on top of the dish soap and finally the oil. It is best if you added food colouring to the water so that it shows up beside the oil. Avoid using the same colour as the soap.

Everyone was very excited to notice that they were creating a rainbow with the liquids!

When children had predicted what would happen, most had expected the liquids to mix, or explode/fizz. They were excited to see the layers they were creating.

As you add each liquid, you will notice that the liquid sits on top of the liquid below.

science experiments for kids
Our ‘Rainbows’ in a Test Tube

What’s Happening?

This experiment is great for teaching density of liquids because it shows that although all liquids share some common properties, such as the ability to be poured, they have different densities.

For young kids, I have them think of density as how ‘heavy’ the liquid is.

Children will begin to look at different liquids and notice the difference in the way they feel, and the way they move. Does the liquid move slow like honey, or fast like water?

Noticing and being aware of these differences helps children learn about the world around them.

It is such an easy science experiment, but everyone has so much fun and learned a lot!

Another great thing about this experiment is that every single child was successful in creating a rainbow in their test tubes. It is a very kid friendly experiment that makes them feel successful.

I love easy science experiments for kids for home or school! In my opinion, learning about these basic science ideas in a hands-on way creates a love for science, but also for learning and exploring. As a teacher, what more could I hope for for my students?

science experiments for kids
Being Scientists

Science Experiments for Kids Extension Ideas

Kids will love creating their rainbow with the science experiments for kids, but there is more that you can do with this after you have completed the rainbow.

After everyone had completed their rainbow, a lot of children were curious what would happen if they mixed up their layers? Would it properly mix? Would it mix, but then settle back in the layers again?

science experiments for kids
Our Completed Density Experiment

We used one of the test tubes and stirred it up to see what would happen. When children are curious about learning something I always try to let them explore to answer their questions – in a safe way.

Many children were also curious what would happen if you added corn syrup on top of the oil? Would it sink down through the oil? Would it sink past the water?

There are so many extension activities that you could do! Children added the corn syrup and watched what happened.

Students even tried adding a few drops of water on top of their oil to see if it would float. They quickly noticed that it sunk through the oil and stayed with the water.

This is a simple experiment to try out! Add a few drops and let children watch what happens.

science experiments for kids

Another question that came up a lot was what would happen if we dropped a small stone into the test tube layers? Would it float? Would it sink?

We ended up adding a few different materials to the test tubes to see what would happen. A small button, a small stone and even a bead. Adding a few different materials is a great way to show the difference in the liquids because some objects will become stuck in different layers. It is interesting to see and watch.

You can try different liquids to check their density. What layer does milk form? What about juice? Just make sure that every liquid you try is safe and children know to only add liquids approved by an adult.

Mixing random liquids can be very dangerous and can cause a very serious reaction. Do not mix any liquids that you are unsure of the reactions.

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