Teacher Aldo stands in the lab.

A kid's bike sits on the lab table.

Teacher Aldo is in his thirties, with short curly black hair and a goatee. He wears glasses and a blue Homework Zone T-shirt.

He says HI, I'M TEACHER
ALDO,
AND WELCOME TO
THE HOMEWORK ZONE.
TODAY, I WANT TO
TALK TO YOU A BIT
ABOUT AIR
PRESSURE,
BUT BEFORE I
CAN TALK ABOUT
AIR PRESSURE,
WE'VE GOT TO TALK
ABOUT WHAT AIR IS.
AIR IS ALL
AROUND US.
IT'S THE
INVISIBLE GAS
ALL AROUND OUR PLANTS,
OURSELVES,
ALL AROUND
OUR PLANET EARTH.
WHAT I HAVE HERE
IS A BICYCLE
TO SHOW YOU
THAT AIR IS ACTUALLY
IN THE TIRES OF
THIS BICYCLE.
OVER THE
COURSE OF THE WINTER,
YOU PROBABLY STORED
YOUR BICYCLE
EITHER IN
YOUR BASEMENT
OR IN YOUR
GARAGE,
AND YOU'RE
ABOUT READY TO TAKE
IT OUT INTO THE NICE
WEATHER,
TO GO FOR
A BIKE RIDE,
BUT BEFORE YOU
DO THAT,
YOU BETTER CHECK
THE AIR PRESSURE
OF THE
TIRES.
HERE IN
THIS BICYCLE,
YOU CAN SEE THAT THE
AIR PRESSURE'S
REALLY LOW.
THAT'S BECAUSE
OVER THE WINTER MONTHS,
THE COLD AIR HAS
ACTUALLY
DECREASED THE AIR
PRESSURE IN THESE TIRES,
AND ALSO, SOME OF
THE AIR ACTUALLY
ESCAPED FROM THE
SIDES OF THE TIRE
AS WELL.
SO WHAT WE NEED TO
DO IS WE NEED
TO FORCE AIR
PRESSURE BACK INTO
THE TIRE,
AND WHAT WE HAVE
HERE IS A
SIMPLE MACHINE
CALLED A PUMP.
IF YOU ATTACH THE
NOZZLE OF A PUMP
ONTO THE
END OF THE TIRE,
YOU CAN ACTUALLY
PUMP AIR BACK
INTO
YOUR TIRE,
AND INCREASE THE
AIR PRESSURE OF
YOUR
BICYCLE TIRE.
RIGHT NOW,
I'M JUST TAKING
A MOMENT AND ATTACHING
THE PUMP TO
THE TIRE,
AND NOW I'VE GOT
TO PUMP UP THE TIRE
SO I CAN GO FOR
A BIKE RIDE.
I'M TEACHER ALDO,
AND NOW YOU KNOW.