Rubber consists of long chain molecules that form a network. This network with its entangled molecules is the secret behind the ability to stretch so much. Upon stretching the chain molecules are aligned until they are all straight resulting in an increase in the resistance to stretch. In this experiment you will explore if stretched rubber is really (air)tight.

rubber balloon[br]ground pepper, vanilla sugar or ground cinnamon

1 Take an uninflated balloon and carefully insert 1-2 tablespoons of fragrant powder (cinnamon, vanilla sugar or pepper) into it.[br][br]2 Start inflating it. [br][br]CAUTION: Be careful not to inhale the fragrent powder.[br][br]3 Tie the inflated ballon.[br][br]Can you smell the fragrance? (1) Yes / (2) No[br][br][br][br]