Slime

Slime is great to play with and does not stick to many surfaces. Be careful of upholstery and curtains. My introduction to slime was a young adult who showed me her slime from high school chemistry class. This is incredibly popular. 

Parents need a heads-up about slime. My big fear is a younger sibling or pet eating the concoction. In short, I never let kids keep it unless a parent is walking out the room knowing the child is carrying it. In one situation, I allowed none of the kids to keep the slime. I knew one of the parents probably needed supervision themselves and there were several small children in the home.
Do I sound paranoid. Thank you. When you teach long enough you get where you are over cautious. You see different things happen that you never expected to see. 

Slime is two parts boric acid solution and one part water and one part polyvinyl chloride.

Since boric acid is poisonous, this is where you need to be cautious with young children. They like to eat or taste substances and they like to feed substances to even younger siblings and pets. Age and maturity are the factors you have to consider. I did this with middle schoolers and then let them take it outside to play with. A little dirt and grass usually convinced most to throw it in the garbage at the end of the school day. I never felt any guilt with making them put their name on a small plastic bag and leaving it with me everyday and keeping any of the precious substance at the end of the year.
Back to how to make slime.

First, dissolve as much boric acid as possible in hot or warm water. You'll have excess which doesn't dissolve in the bottom of the container. I stored material like this in a bottle labeled with the substance and the words poisonous and literally drew a skull and crossbones on the container. Do I sound paranoid? One thing you learn in over 30 years teaching, things will happen that you never expected. Prevention is much easier believe me.

Second, polyvinyl chloride. You can buy some expensive pure product from a chemical supply company with warnings that make you incredibly uneasy and dilute it or you buy a gallon jug of Elmer's Glue. Polyvinyl chloride is its main ingredient.

Actual instructions:
Measure 1 tablespoon of glue and put in a plastic bag.

Add 1 tablespoon of water.

Knead mixture until thoroughly mixed.

Add 2 tablespoons of boric acid solution.

Knead mixture. It will change from a liquid to a viscous semi-solid.

To give color, I have added food coloring to the water.