Silly Putty is the trademarked name for a simple toy that children can stretch, bounce and form into shapes. Kids and parents can make their own version of Silly Putty with cornstarch and water. Cornstarch "goop" tends to be slimier than the commercial version, but kids will enjoy making shapes from the tactile substance.
Boil water in a saucepan. This recipe mixes 128 g (1 cup) cornstarch with 946 ml (4 cups) of water.
Add cornstarch to the water a little at a time, stirring constantly. Continue stirring until the mixture is smooth.
Add a few drops of food colouring to the mixture, if desired. Food colouring will make the putty more appealing to children, but it may stain fingers and surfaces.
Remove the mixture from heat and allow it to cool. Allow children to play with the putty on a covered surface.
Store putty in a plastic container with an airtight lid.
Use as much or as little water and cornstarch as you need, depending on whether you're working with one kid or a group.