CNET también está disponible en español.

Ir a español

Don't show this again

Smart Home

Everything you need to know about slime

Is it safe? Why is it popular? How is it made?

Getty Images

Slime has been a popular science project for decades, teaching kids about viscosity, polymers and chemical reactions. In the last few years it has become a bona fide cultural phenomenon, with viral how-to videos taking over social media.

While many jumped on board with this fun trend, some became concerned about how safe slime was. Was the fun worth the risk? How can you make it safely and without allergens? 

Here's everything you need to know about the world's squishiest craft.

Now playing: Watch this: Make DIY slime without using borax
1:30

What is slime?

A surprisingly humble cultural phenomenon, slime is a mixture of household items that come together to create a polymer substance that acts like both a solid and a liquid, depending on how you play with it. This is called a non-Newtonian fluid.

Making slime and playing around with it is a great way to teach kids science principles.

Why do people love slime?

Other than the sheer fun of learning science, slime is popular for several reasons. Some find it satisfying to watch slime turn from a solid to a liquid and back again. 

Squishing it between your fingers can also be a great way to relieve stress. And some people just like it because it's gooey and fun to stretch. 

Personally, I find it fascinating watching basic ingredients turn into something completely different with just a few minutes of stirring. I also use a special type of slime to clean electronics.

What are the different types of slime?

Slime can be made in many different varieties. Here's a sample of some of the most popular. Each of these links will take you to a video that shows how to make it.

  • Glitter slime or unicorn slime: Just a basic slime recipe with glitter mixed in. 
  • Cleaning slime: This is a thicker slime that works almost like a lint brush to get crud out of your keyboard and other electronics.
  • Fluffy slime: This slime feels like a soft marshmallow when you squish it.
  • Popping slime: Styrofoam pellets or other beads mixed in with regular slime make this one a sensory delight. 
  • Borax-free slime: Some people who are concerned about how harsh borax (a cleaning agent) can be on the skin opt for slime recipes without it.
  • Glow-in-the-dark slime: Yes, it really does glow in the dark and it can be made at home with nontoxic items.

Basic fluffy slime.

Alina Bradford/CNET

How do I make slime?

Slime can be made with a wide range of items. Slime recipes usually include at least a couple of these ingredients: 

  • Borax
  • Liquid laundry detergent
  • Contact solution
  • White school glue 
  • Cornstarch
  • Shaving cream
  • Shampoo
  • Glitter
  • Food coloring

To make cleaning slime, for example, you'll need borax laundry booster, warm water and white school glue. Here's the recipe. The American Chemical Society has a recipe for a stretchier slime here.

Fluffy slime typically takes more ingredients because it has a different texture. It's also borax-free.  

A good, basic recipe for borax-free slime calls for 4 ounces (120 ml) of white school glue, 1/2 tablespoon of baking soda and 1/4 tablespoon of contact solution. Put the ingredients in a bowl in the order listed, then mix them together for several minutes until it turns into slime. It should be moist and stretchy, but not sticky. 

Need something a little cooler and less basic? You can make glow-in-the dark slime with a similar recipe. Here's the instructions.

How long does slime last?

Storing it in an airtight container is key. This will keep it from drying out and will make it last several days. If you store the container in the fridge, you can get slime to last as long as a month without drying out or molding.

Is slime safe?

Generally, yes. Some people have skin reactions to various ingredients, depending on allergies or skin sensitivity. For example, my daughter gets rashes when exposed to certain laundry detergents, so we stay clear of those recipes.

Most importantly, don't eat it or give it to a child who may put it in its mouth. Ingredients like saline solution and borax can make a person ill.

Read moreThese tiny toilet paper crafts are anything but crappy

Read next20 unexpected ways to use dryer sheets