- [Narrator] Behold, the microwave,
but where did it come from?
Meet Percy Lebaron Spencer,
born in Maine in 1894.
Percy grew up with his aunt and uncle,
and by the time he was 12,
he'd left school to apprentice at a mill.
In the navy, he studied
wireless telegraphy
and when he joined the
Raytheon Company in the 1920s,
he established himself
as an electrical genius.
His improvements to
magnetrons boosted production
from 17 per day to over 2,500 per day.
But his biggest
inspiration struck in 1945,
when an operating magnetron melted
the chocolate bar inside his pocket.
When Percy placed popcorn
in front of the bean,
the kernels popped.
He wondered, could it be possible
to cook food using microwave radiation?
Raytheon knew a good
thing when they saw it,
and in 1954, the company began selling
an innovative little gadget
called the microwave oven.
Of course, the original
microwave oven weighed 750 pounds
and stood over five feet tall.
This first microwave oven
model was called the Radarange.
Microwave ovens use radio waves
with a frequency of about 2.5 gigahertz.
At this frequency, radio waves are
absorbed by sugars, waters and fats,
but not by most plastics,
ceramics or glass.
These waves are converted into
heat when they're absorbed,
which means that a microwave oven
essentially only heats the food.
As a side note, metal
will reflect microwaves,
which is why you shouldn't use
metal plates or foil in these devices.
After decades of research, improvement
and a lot of miniaturization,
the microwave oven became
a common sight in
kitchens across the world.
