My Sister asked me this:
"Why is it that when we chew gum, it is soft and mushy to begin with , but slowly gets firmer and firmer like after 20 mins of chewing?"
I think it is because when we initially chew gum it has plenty of sugar causing rapid salivation and hence mushiness and the rubber polymer is very flexible to begin with and slowly looses its elasticity hence becomes firmer.
Is this the reason?
What is the chemistry involved ?