Students multiply by a scale factor to find the proper amount of ingredients to use to make a play putty. The measurements are in metrics to support the science classes. You will need white school glue, water, a way to heat water, borax, and food coloring. I use baggies to mix the ingredients for easy clean up. Keep wipes on hand. You can find many recipes for this, my spin is changing the amounts and having the students practice multiplying by a scale factor to find what they need.