Everyone enjoys making slime!!! Slime is an easy and fun way to teach about polymers and cross linking. This slime kit contains one liter of colorless, 4% polyvinyl alcohol - initially clear, but it can easily be colored using food dyes - and enough sodium tetraborate solution to cross-link with it. A preservative has been added to avoid the growth of unwanted creatures. Investigate a cross-linked polymer. If pulled slowly, it flows; if pulled quickly, it breaks; and if rolled into a ball, it bounces. Enough for more than 60 students to make a 1/2 ounce portion (~15 cc). IMPORTANT COLD WEATHER SHIPPING: Our slime making chemicals can be affected if they are left out in sub-freezing temperatures. Please choose a shipping location that can accept your order when it arrives.