National Slime Day Date in the current year: December 7, 2024

Slime is a toy product that consists of a viscous, squishy and oozy material. Its viscosity depends on pressure that is applied to it because slime is a so-called non-Newtonian fluid; slime flows like a liquid under low stresses and becomes more viscous under higher stresses.

The first slime-like toy was Silly Putty. It was originally created during research into potential substitutes for rubber during World War II. In 1949, toy store owner Ruth Fallgatter and marketing consultant Peter C. L. Hodgson decided to market the putty as a toy. Although the new toy sold well, Fallgatter didn’t pursue it further, but Hodgson saw its potential and eventually achieved success. The Silly Putty became a hit in the United States by the mid-1950s and spread to Europe in the early 1960s. After Hodgson’s death in 1976, the Silly Putty brand was purchased by the Binney & Smith Company (now Crayola).

However, Silly Putty was just a beginning. The toy we now call slime was first released by Mattel in 1976. Made of a combination of guar gum, borax, and water, it was less adhesive than Silly Putty and had a stretchy, viscous texture that kids couldn’t get enough of. Other manufacturers soon started to produce their own versions of slime and introduced a new formula based on a combination of polyvinyl alcohol (PVA) and borax.

Today, slime is extremely popular among children and adults alike because this toy has a number of benefits. Playing with it can be good for kids because it improves their sensory development and fine motor skills, as well as helps them focus. As a stress toy for people of all ages, slime decreases symptoms of anxiety and helps to calm down.

Although you can easily buy slime produced by various brands, homemade slime is becoming increasingly popular because making slime is a fun activity that helps introduce kids to basic chemistry and boosts their creativity as they experiment with colors and textures. Just make sure to supervise your kids during their experiments.

The standard homemade slime ingredients are white glue (PVA glue), borax (or a contact lens solution that contains boric acid), baking soda, and food coloring. Ingredients like corn starch or shaving cream can be added to change the texture of the slime, and adding glitter is a great way to make your slime even more fun.

National Slime Day was launched in 2022 by Ace Slime LLC, a company that produces custom slimes inspired by popular treats, in collaboration with National Day Calendar. The main goal of the holiday is to celebrate the gooey goodness that is slime and promote its benefits for kids of different ages.

There are many ways to celebrate National Slime Day. You can buy some slime and play with it (it can be fun regardless of how old you are), try making your own slime, give slime as a gift to your kids, niblings, young cousins, or friends, and post about the holiday on social media with the hashtag #NationalSlimeDay to spread the word.