To demonstrate how mixing two chemical together can form another chemical - slime!
Additional information
Slime, as defined by Webster’s dictionary, is:
1. thin, glutinous mud.
2. any ropy or viscous liquid matter, esp. of a foul kind.
3. a viscous secretion of animal or vegetable origin.
Despite slime's grotesque characteristics and definition (the name alone is vile), many children and adults have a strange fascination and fondness for it, mostly due to toy companies creation of products that take on the characteristics described above, often with bright glowing hues of green. Manufactured "slime" is slightly wet to the touch, stretchy, bouncy, and usually large. In contrast, natural slime moulds are often brown, white, or yellow in color and are only a few centimeters small.