Light Experiments with Slime

Create moldable lenses with clear slime and lasers

What you'll learn:

How to make clear slime, and how light interacts and refracts through slime.

Key takeaways:

The bend in the slime is what makes the laser light refract, or bend.

Light Experiments with Clear Slime

Playing with slime is a classic science activity for kids. As you make slime you learn about chemistry, polymers, and measuring. But what about learning science after you make the slime? What about science you can do while playing with slime?

Using our easy clear slime recipe kids will get to make clear slime and engage in some fun light experiments using their slime, laser pointers, and if you desire, plastic lenses (which I suggest). If your kids enjoyed this light experiment you can also check out our edible optics light experiment. Similar to making lenses out of slime, in our edible optics activity kids will make lenses out of gelatin (aka Jello). 

Bringing light experiments into your home is going to be a ton of fun.

Light experiments with clear slime: What to do

  1. Mix up a batch of clear slime
  2. Make various shapes with the slime and see how the laser goes through the clear slime
  3. Ask kids to see if they can make the light rays come together (make a converging lens)
  4. Ask kids to see if they can make the light rays spread apart (make a diverging lens)
  5. Compare and contrast their clear slime lenses with the acrylic lenses
clear slime light experiments for kids collage
Use our clear slime recipe in light experiments
Clear slime for kids opens the door to light experiments
making lenses out of slime

Doing light experiments with clear slime

1. Make clear slime

If you want to do light experiments while playing with slime you will need clear slime. Why clear, and not white, or colored slime? White slime is opaque, that is, it eats up all the light that hits it. If you want to see your laser light and how it interacts with the slime you won’t see much since the slime will gobble it up.

Why not my favorite color of slime? The colors we see are the colors reflected in our eyes. If you wear a red shirt it means the material in that shirt eats up (or absorbs) all of the colors but red. If we think of picky eaters, the red shirt will always refuse to eat its red vegetables. If you color your clear slime you might well turn it into a colored slime that will eat your laser. 

Instead, you want your laser to go through your slime. That means you either need clear slime or translucent slime that is the same color as your laser. 

2. Make shapes with your clear slime and see how the laser interacts

The first of many light experiments with your clear slime is just playing with slime and your laser. How does the slime interact with the laser? How do curves in the slime bend the laser? Does the thickness of the slime matter? 

3. Challenge kids to make a slime shape that brings the laser light together (a converging lens)

As kids play with the slime they should get a feel for how different curves bend the laser light differently. If they are having trouble you can break out the acrylic lenses and look at those. Once you find an acrylic lens that brings lines of light together ask kids to make the same shape in their own slime. 

4. Challenge kids to make a slime shape that spreads the laser light apart (a diverging lens)

This is opposite #3. In this light experiment, you will need to find a new type of curve that will spread the light apart. You can again look at the acrylic lenses to get an idea, and then shape your slime from those.

More fun light experiments for kids

If your kids had a ton of fun playing with slime and learning about light they might enjoy these other light experiments:

optical jellyfish ray tracing

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