Teacher Aldo stands in the lab.

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 THERE,
IT'S TEACHER ALDO HERE.
WELCOME TO THE HOMEWORK ZONE.
TODAY, I GOT A FANTASTIC
EXPERIMENT TO SHARE WITH YOU
ABOUT AIR PRESSURE.
BUT BEFORE WE GET
TO THE ACTUAL EXPERIMENT,
LET'S TALK ABOUT
WHAT AIR PRESSURE IS.
AIR PRESSURE IS
THE AIR AROUND US.
IT'S INVISIBLE. WE CAN'T SEE IT,
BUT WE CAN FEEL IT.
YOU SEE, AIR IS MADE UP OF
TINY PARTICLES
AND THOSE PARTICLES ARE ACTUALLY
PRESSING ON OUR SKIN,
EVERYDAY OF OUR LIVES.
IN FRONT OF ME,
I'VE GOT AN EXPERIMENT
THAT I WANT TO SHOW YOU
ABOUT HOW WE CAN ACTUALLY
DEMONSTRATE AIR PRESSURE.
WHAT YOU'RE GOING TO NEED IS A
BOWL FULL OF ICE,
YOU'RE GOING TO NEED AN EMPTY
BOTTLE OF WATER,
YOU'RE GOING TO NEED
SOME WARM WATER,
AND YOU'RE GOING TO NEED A
PARENT OR GUARDIAN BESIDE YOU
TO MAKE SURE
EVERYTHING GOES WELL.
FIRST THING THAT
WE'RE GOING TO DO
WE'RE GOING TO EMPTY THE BOTTLE
OF WATER, REMOVE THE LID.
AND WE'RE GOING TO PUT IT INSIDE
THE BOWL WITH ICE.
AND THE NEXT THING
WE'RE GOING TO DO...
WE'RE GOING TO CAREFULLY POUR
SOME WARM TAP WATER
INSIDE THE BOTTLE.
TRY TO FILL IT UP TO ABOUT
ONE QUARTER OF ITS HEIGHT,
SEE THE STEAM THERE, THAT'S OUT
OF THE TAP. NICE AND WARM.
NEXT THING WE'RE GOING TO DO,
WE'RE GOING TO QUICKLY
COVER IT WITH OUR LID,
AND WE'RE GOING TO
WATCH WHAT HAPPENS.
YOU'RE GOING TO SEE SHORTLY THAT
THE SIDE OF THE BOTTLE
WILL START TO CONTRACT.
INSIDE, THE AIR PRESSURE IS
DECREASING.
WHAT'S HAPPENING IS THAT THE ICE
IS WARMING UP THE AIR INSIDE
AND THE AIR IS ACTUALLY EXERTING
A PRESSURE INSIDE
AND NO LONGER ON THE
SIDE OF THE BOTTLE.
AND THE AIR OUTSIDE IS ACTUALLY
PRESSING AGAINST THE BOTTLE,
AND PRETTY SOON YOU'RE GOING TO
SEE THE ENTIRE BOTTLE COLLAPSE.
TO TRY TO SPEED IT UP A BIT,
WHAT YOU CAN DO IS MAKE SURE
IT'S ALL NICE AND COOL
WITH THE ICE AROUND IT.
TAKE A LOOK AT THE SIDES.
THAT'S AIR PRESSURE ACTION.
I'M TEACHER ALDO,
AND NOW YOU KNOW.