WORD WIZARDRY DICTIONARY
Accelerate: go faster (speed up)
Decelerate: go slower
iTECH
Reaction time: how long it takes to
react, e.g. between seeing the car go
too far left and actually turning the
steering wheel to the right
Do you think this kind of technology will be adapted for
cars in the future?
Just because someone says something was impossible
yesterday doesn’t mean it is tomorrow. When Andy
Green first broke the landspeed record in the world’s first
supersonic car, he’d been told it was impossible to break
the sound barrier at ground level. But 50 years earlier it had
been impossible to break the sound barrier in an aeroplane.
Did You Know?
Anna’s hummingbird
is the fastest bird in
the world for its siz
e. It’s only 10cm long
,
but when it dives to
wards the ground it
can
reach speeds of ne
arly 60 miles per ho
ur
.
Scientists found th
at when this tiny No
rth
American bird pulls
up at the end of the
dive it experiences
forces of 10 G – en
ough
to make any human
faint (go unconscio
us).
So what do we mean by “the sound barrier”?
Sound travels at about 760mph through
the air. The next time you hear an
airplane flying over, look up. You’ll notice
that the sound seems to be coming
from quite a long way behind the plane.
It didn’t – it came from the plane, it’s
just that it took more than 15 seconds to
travel from the plane to your ears.
Sound is actually small movements of air.
When an airplane moves through the air
at 500mph, the sound of the engines can
move away from the plane because it’s
faster than that. But what happens if the
plane travels even faster, as fast as the
sound? Then the air in front of a plane is
squashed together and can’t move freely.
Eventually the air breaks free and crashes
behind the plane, making a dramatic noise
called a sonic boom. It’s particularly hard
for the plane’s engines to push through
that squashed air, which is why it’s called
the “sound barrier.”
SPARK
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