What do people need to see clear?
glasses
are they important?
yes
Who created them?
Alessandro di Spina
When?
In 1282
what was their purpose?
help people to see
did they work?
yes
how?
scientists didn't understand how
did they ever find out how?
yes
who found this?
Johannes Kepler
did they always stay the same?
no
what changed?
they continued to improve
how?
bifocal lenses
who made those?
Ben Franklin
were there other changes?
yes
by who?
George Airy
what did he change?
made circle-shaped glasses
what was their purpose?
to correct an eye problem
Who used glasses first?
The Chinese
for what?
fashion
what did they think of them?
they had magic