recycling Structure and properties of polymers
Age Group
15 16 17 18
Expected time
2 periods 3 periods
What happened to the cup.PDF
beaker symbol

What happened to the cup?

What’s the mystery? Transparent plastic cups are disposable and have thin walls. They are available in vending machines and are primarily used for cold drinks. Are there reasons why this type of cups are not used for hot drinks, like coffee or tea?
Domain(s) Physic
Subdomain keywords Structure and properties of polymers, recycling
Age group Can be done at age 15-16 without going into glass transition temperatures and structures; age 17-18 with a more detailed look at polymer structure and properties.
Expected time for the mystery 2-3 lessons
Safety/supervision None
Disclaimer: The authors of this teaching material shall not be held responsible for any injury or damage to persons or properties that might occur in their use.
Resources Further hints:
Unbreakable bubbles

Magic plastic bubbles – ar. £4 per tube (available in toy shops)

Blow moulding

Making PET bottles from a former.

Using PET to make bottles and its properties

Slideshow on the development of plastic cups to make them more heat resistant:

See also:

Authors Peter E. Childs