Transcript: Simple Gears - ST3 | Sep 15, 1998

Lorraine sits in the studio. She is in her early thirties, with long straight red hair with bangs in a low ponytail. She wears a short sleeved purple sweater and a pair of earrings.

She says
GOOD MORNING, AND WELCOME
TO TVO'S VIRTUAL CLASSROOM.
OUR CLASS TODAY IS
ON SIMPLE GEARS.
I'M GOING TO ASK YOU A
QUESTION, SO YOU WILL REQUIRE
YOUR PHONES AT THIS POINT.

A question appears on screen that reads “Do you know how to mount an axle and gear or your vehicle frame? 1- Yes. 2- No.”

Lorraine says IF IT'S YES, YOU PRESS ONE,
PUT DOWN THE RECEIVER.
IF IT'S NO, PRESS TWO,
AND PUT DOWN THE RECEIVER.
I HAVE ALMOST 50 PERCENT
OF YOU WHO HAVE ANSWERED.

The results appear in a bar graph. 17 students answered “Yes” and 11 answered “No.”

Lorraine says IF WE LOOK AT OUR BAR GRAPH
HERE WE NOTICE THAT THERE'S
MORE OF YOU THAT HAVE MOUNTED
AN AXLE GEAR ON YOUR VEHICLE
FRAME, AND THERE ARE SOME
OF YOU THAT HAVE NOT.
SO WE WILL BE GOING OVER THAT
DURING THE LESSON, BRIEFLY.
NOW, JUST TO LET YOU KNOW WHAT
WE ARE DOING DURING OUR LESSON
TODAY... THE FIRST THING
WE'RE GOING TO TALK BRIEFLY
ABOUT THE MATERIALS THAT
YOU REQUIRE FOR THE CLASS,
FOLLOWED BY HOW TO PUT
THE MATERIALS ON YOUR
VEHICLE FRAME.
AND IN A LITTLE MORE LENGTH,
WE'RE GOING TO TALK ABOUT RATIOS
OF GEARS, SO YOU UNDERSTAND
FOR SIMPLE GEARS TODAY.
AS WELL, ABOUT YOUR
DESIGN LOG AND LOG FOLDER.
AND THEN WE'LL TALK TO
YOU ABOUT YOUR HOMEWORK.
NOW WHEN WE TALK TO YOU ABOUT
YOUR MATERIALS, IF YOU LOOK
HERE -- I WOULD LIKE YOU TO CALL
IN BY PRESSING POUND NINE --
AND LET ME KNOW, WHAT ARE
THE NAMES OF THE OBJECTS YOU
SEE HERE, THE MATERIALS?
SO IF YOU CAN PRESS POUND NINE
AND LET ME KNOW WHAT YOU SEE
ON THE SCREEN HERE.

She shows some locknuts and gears.

Lorraine says CALLING SOMEONE
FROM SOUTHWOOD PARK.
HELLO.

The caller says HELLO?

Lorraine says HI.
IF YOU'RE LOOKING AT THIS
WHITE THING HERE -- IT'S VERY
HARD TO SEE.
MAYBE IF WE ZOOM IN A TAD.
DO YOU KNOW WHAT
THAT'S CALLED?

The caller says A DRIVE COLLAR?

Lorraine says NO.
IT STARTS WITH AN --

The caller says AXLE BUSHING?

Lorraine says PERFECT.
EXACTLY.
SO IF SOME OF YOU AREN'T AWARE
OF THAT, MAYBE YOU'D WANT
TO WRITE THAT DOWN.
SO HERE IT IS CALLED
AN AXLE BUSHING.
OKAY.
AND YOU WILL REQUIRE
TWO OF THOSE FOR TODAY.
NOW HOW ABOUT THIS
BLACK THING OVER HERE?
AND WE'LL TRY SOMEONE HERE
FROM SOUTHWOOD PARK ONCE AGAIN.
IT'S BLACK.
IT'S CIRCULAR.
IT'S GOT A LITTLE HOLE --

The caller says HELLO?

Lorraine says DO YOU KNOW WHAT
THIS IS CALLED?

The caller says A RUBBER SPACER.

Lorraine says PERFECT.
RUBBER SPACER.
SO ONCE AGAIN, YOU
CAN WRITE THIS DOWN.
AND YOU WILL REQUIRE
TWO OF THOSE.
NOW LET US TRY --
THANK YOU.
HI.
HELLO?
OKAY, WE'RE GOING TO TRY
SOMEONE FROM THE PINES.
YOU CAN SHARE WITH US
WHAT THESE OBJECTS ARE.
HELLO.

The caller says AN AXLE.

Lorraine says PERFECT.
AN AXLE.
AND FOR TODAY,
YOU JUST NEED ONE.
CAN YOU CONTINUE?
THERE'S A GREY
OBJECT OVER HERE.
DO YOU KNOW WHAT THAT IS?

The caller says NO.

Lorraine says OKAY, HOW ABOUT THESE?

The caller says WHEELS.

Lorraine says OKAY.
THEY DO LOOK LIKE WHEELS, BUT
WE GIVE THEM A SPECIAL NAME.
AND THEY ARE...?

The caller says GEARS.

Lorraine says YEAH, VERY GOOD.
AND I'LL TAKE MY PICTURE OUT
OF THERE SO WE CAN WRITE
THAT DOWN.
WE HAVE GEARS.
SO YOU MIGHT WANT TO WRITE
THAT WORD DOWN SO WE'RE ALL
COMMUNICATING IN
THE SAME LANGUAGE.
THANK YOU.
AND FROM THESE GEARS YOU'RE
GOING TO NOTICE THEY'RE
DIFFERENT SIZES, AND WE'LL SEE
IF SOMEONE FROM SOUTHWOOD PARK
CAN LET US KNOW
WHAT THE SIZES ARE.
HELLO.

The caller says HELLO?

Lorraine says HI.
DO YOU KNOW WHAT THE NAME
OF THIS GREY THING IS?

The caller says THAT'S A DRIVE COLLAR.

Lorraine says PERFECT.
DRIVE COLLAR.
AND ACTUALLY YOU CAN
STAY ON THE LINE.
HI.

The caller says HI.

Lorraine says COULD YOU TELL US -- DO YOU
KNOW HOW MANY TEETH ARE ON
THESE GEARS?

The caller says THE BIG ONE IS 75.

Lorraine says PERFECT, 75.

The caller says THE LITTLE ONE IS 45.

Lorraine says 75 TEETH.
YOU MIGHT WANT TO WRITE THIS
DOWN BECAUSE THAT'S WHAT
YOU'RE GOING TO BE USING AT
ALL TIMES FOR ALL OF YOU.
SO 45, PERFECT.
AND HOW ABOUT THE LITTLE ONE?

The caller says AND THE LAST ONE IS 15.

Lorraine says PERFECT, 15 TEETH.
GREAT.
THANKS VERY MUCH.

The caller says OKAY, BYE.

Lorraine says BYE.
ALL RIGHT, I'LL LEAVE IT ON
FOR A FEW MORE SECONDS SO YOU
CAN MAKE SURE YOU HAVE
THAT WRITTEN DOWN.
SO WHEN I'M COMMUNICATING WITH
YOU AND SAYING RUBBER SPACERS,
YOU KNOW THAT IT'S THE
BLACK OBJECT AND SO ON.
ALL RIGHT.
WELL, AT THIS POINT, VERY
QUICKLY, I'M GOING TO SHOW YOU
HOW TO MOUNT THE MATERIALS
THAT WE'VE JUST TALKED ABOUT
ONTO YOUR VEHICLE FRAME.
AND THE VEHICLE FRAME IS THE
LARGEST OBJECT IN YOUR KIT.
AND THIS IS WHAT
IT LOOKS LIKE.
OKAY.

She shows a structure made out of two rectangles of pegboard board joined in the corners by 4 steel sticks.

Lorraine says SO WHEN I MENTION VEHICLE
FRAME, YOU'LL KNOW
THIS IS THE OBJECT.
AND SO IF YOU HAVE THE
MATERIALS IN FRONT OF YOU,
MAYBE YOU WOULD LIKE TO ASK
THE PERSON WHO HAS NEVER DONE
THIS BEFORE TO HAVE THE
EXPERIENCE, OR THE PERSON
THAT'S TOUCHED THE MATERIALS
THE LEAST AMOUNT, WOULD BE THE
IDEAL CANDIDATE TO TRY THIS
WHILE I'M DOING IT ON SCREEN.
OKAY.
SO IF WE LOOK HERE.
YOU HAVE YOUR VEHICLE
FRAME IN FRONT OF YOU.
YOU WILL NEED TO
AXLE BUSHINGS FIRST.
OKAY.
THE AXLE BUSHING, ONCE AGAIN,
IS THE LITTLE WHITE OBJECT.
NOW, THERE'S A LITTLE GROOVE
THERE AND THEN THERE'S A LONG
SECTION AND THEN
A SHORTER ONE.
YOU WANT TO HAVE THE LITTLE
GROOVE, AS YOU CAN SEE,
STICKING ON THE OUTSIDE AND
THE LONGER SECTION IN THE
INSIDE HERE.
OKAY.
AND YOU PICK
ANYWHERE YOU LIKE.
JUST FIND A HOLE,
JUST FOR TODAY.
AND THEN OBVIOUSLY YOU'RE
GOING TO HAVE TO MAKE IT GO TO
THE OTHER SIDE AS WELL.
SO AN EASY WAY OF DOING THAT,
YOU CAN PUT YOUR AXLE THROUGH
THE HOLE HERE OF THE AXLE
BUSHING AND THEN YOU CAN SEE
THAT THIS IS WHERE YOU'RE
GOING TO HAVE TO PUT YOUR
OTHER AXLE BUSHING.
SO YOU KEEP THAT IN MIND.
THEN YOU TAKE THE AXLE
BUSHING, PUT THE WHOLE THING
INSIDE HERE, AND THEN YOU GOT
TO CLIP IT RIGHT THROUGH, AND
IT'S JUST THE SMALLER PORTION
OF THE AXLE BUSHING...
THAT GOES THROUGH.
AND DID YOU HEAR THAT SNAP?
I'LL BRING IT UP A
LITTLE BIT CLOSER.
AS YOU CAN SEE HERE, JUST THE
SMALLER SECTION STICKING OUT
AND THE LONGER SECTION'S
INSIDE, INTERIOR.
SO YOU SHOULD HAVE
TWO OF THEM IN THERE.
OKAY.
NOW AT THIS POINT,
YOU NEED YOUR AXLE.
YOU PUT IT THROUGH THE TWO
AXLE BUSHINGS LIKE THAT.
THEN YOU WILL REQUIRE
RUBBER SPACERS.
PUT THEM AT BOTH
ENDS OF THE AXLE.
IT'S A LITTLE BIT -- SO YOU GOT
TO PUT A BIT OF PRESSURE AND
TURN IT INWARDS.
THEN YOU WILL TAKE ANOTHER
RUBBER SPACER AND PUT IT ON
THE OTHER SIDE, SO THAT THIS
PREVENTS THE AXLE -- SEE, RIGHT
NOW, IF I DON'T HAVE IT IN
THERE, IT CAN COME RIGHT OUT
AND THAT'S WHAT YOU
WANT TO PREVENT.
SO YOU PUT IN ANOTHER
RUBBER SPACER.
YOU GOT TO PUT A BIT OF
PRESSURE ONCE AGAIN.
YOU CAN TURN IT.
IT DOES HELP.
JUST LIKE THAT.
OKAY.
AND IF YOU WANT, YOU CAN HAVE
BOTH ENDS ABOUT THE SAME.
OKAY.
SO IF YOU LOOK AT THAT A
LITTLE BIT CLOSER, YOU SEE
YOUR TWO RUBBER SPACERS WITH
YOUR TWO AXLE BUSHINGS.
NOW YOU'RE READY
TO MOUNT THE GEAR.
WELL TODAY, I'M GOING TO
CHOOSE THE 45-TEETH GEAR.
OKAY.
AND IN ORDER TO PUT IT ON, WE
NEED TO HAVE A DRIVE COLLAR.
OKAY.
AND YOU'LL NOTICE YOUR DRIVE
COLLAR HAS A SECTION THAT'S
PROTRUDING AND A SECTION
THAT'S INDENTED.
OKAY.
AND YOU'LL NOTICE AS WELL ON
YOUR GEAR, THERE'S A SECTION
THAT'S STICKING OUT.
SO THAT PART OF THE GEAR WILL
GO INTO THE INDENTED PART OF
THE DRIVE COLLAR.
AND YOU'LL NOTICE THERE'S
LITTLE GROOVES AND SO ON --
IF I COME IN JUST A TAD CLOSER.
SEE THE THREE GROOVES?
AND THEN THERE'S THREE
SECTIONS THAT ARE A LITTLE
BIT STICKING OUT.
WELL, THAT'S WHERE
YOU PUT IT IN.
SO IF WE CAN DO THAT.
OKAY.
AND IT SHOULD FIT NICELY AND
THE SECTION STICKING OUT HERE
SHOULD BE OF THE DRIVE COLLAR.
IT'S OUTSIDE YOUR GEAR.
NOW YOU'RE READY TO PUT
THE GEAR ONTO THE AXLE.
AND AGAIN, ON YOUR AXLE,
YOU'RE GOING TO NOTICE THERE'S
A PART HERE THAT'S
INDENTED A LITTLE BIT.
AND IF YOU LOOK INSIDE THE
DRIVE COLLAR, THERE'S A LITTLE
BALL IN THERE, AND THAT GOES
INTO THE GROOVE SECTION THERE,
AND SO YOU GOT TO PUT A TAD OF
PRESSURE, OKAY, AND THERE IT IS.
IT'S READY.
IF IT'S TOO TIGHT, TOO STIFF
AND YOU CAN'T TURN IT, THAT
MEANS YOU JUST GOT TO PUT A
LITTLE LESS PRESSURE WITH THE
RUBBER SPACERS.
OKAY?
SO THAT'S WHAT IT
SHOULD LOOK LIKE.
AND IF EVERYBODY DOES IT
THE SAME WAY, THEN WE'LL BE
COMMUNICATING IN
THE SAME LANGUAGE.
OKAY.
AND IT SHOULD TURN
FREELY LIKE THAT.
AT THIS POINT, IF YOU HAVE ANY
QUESTIONS, PLEASE FEEL FREE TO
CALL BY PRESSING POUND NINE,
AND THIS WAY I CAN ANSWER ANY
OF YOUR QUESTIONS AS FAR AS
PUTTING THE MATERIALS TOGETHER.
I DO NOTICE THERE'S ONE CALL
FROM SAINT JEAN BREBEUF.
AND WHILE WE'RE WAITING FOR
THE CALL, JUST TO LET YOU
KNOW, WE'LL BE WATCHING A
SHORT VIDEO OF APPROXIMATELY
TWO MINUTES WHERE I WILL BE
ASKING YOU TO PAY LOTS OF
ATTENTION BECAUSE I'M GOING TO
ASK YOU QUESTIONS AFTERWARDS.
HELLO.

The caller says HI.
I HAVE A QUESTION.
WHY DID YOU PUT THE
GEAR ON THE OUTSIDE?

Lorraine says ON THE OUTSIDE OF
THE VEHICLE FRAME?

The caller says YEAH.

Lorraine says JUST FOR THIS CASE BECAUSE
TODAY WE'RE GOING TO BE
DEALING WITH GEAR RATIOS, AND
I WANT TO SHOW YOU HOW THE
RATIOS WILL FORM TOGETHER.
FOR INSTANCE, IF WE LOOK AT
ANOTHER ONE OF MY VEHICLE
FRAMES, I'VE PUT TOGETHER TWO
GEARS LIKE THIS WHERE I CAN
GIVE YOU AN OPPORTUNITY LATER
TO SEE HOW THE GEAR RATIOS FORM.
OKAY?

The caller says THANK YOU.

Lorraine says BYE.
AND I NOTICE THERE'S ONE MORE
CALL FROM SOUTHWOOD PARK.
HELLO.

The caller says HI.
I DON'T HAVE A QUESTION
BECAUSE SOMEONE IN MY GROUP
SAID I DID, BUT I DON'T.

Lorraine says OH, OKAY.
THAT'S ALL RIGHT.
THANKS.
ALL RIGHT, AT THIS POINT, TO
LET YOU KNOW, WE'RE GOING TO
WATCHING A SHORT VIDEO,
OF SMALL ENGINE REPAIR,
AND THE TEACHER, OR THE
PROFESSOR IS ANDREW MARQUETTE
FROM NORTHERN ONTARIO, AND
THAT'S WHERE IT WAS FILMED.
AND HE WILL TALK TO YOU
BRIEFLY ABOUT GEAR RATIOS.
I'D LIKE YOU TO PAY LOTS OF
ATTENTION BECAUSE THERE'LL BE
A FEW QUESTIONS AFTERWARDS.
ENJOY.

A video rolls with the caption “Mechanical Science. Gears.”

Andrew is in his workshop. He is in his mid-thirties, with slightly long straight brown hair with bangs. He wears jeans and a green shirt with a print on the front.

He says I'M BACK IN THE SHOP AND THE
NEXT BIT OF MECHANICAL SCIENCE
I WANT TO DEAL WITH
CONCERNS GEARS.
EVERY ENGINE HAS GEARS.
NOW THEY MAY SEEM A LITTLE
DIFFICULT TO UNDERSTAND,
BUT I'LL TRY TO MAKE IT
A LITTLE EASIER FOR YOU
TO UNDERSTAND THEM.
I HAVE A CUTAWAY HERE, AND
WE'RE GOING TO TAKE A LOOK AT
THE GEARS USING THIS CUTAWAY.
FIRST THING YOU HAVE TO
THINK ABOUT IS THESE ARE
STRAIGHT CUT GEARS.

He moves his hands intertwining his fingers.

He says THEY MESH LIKE THIS AND
THEY CONTINUE TO MESH.
NOW IF WE TAKE A CLOSE LOOK AT
THESE GEARS, YOU CAN SEE HOW
AS I TURN THEM AROUND, THEY
SIMPLY MESH LIKE MY FINGERS DID.
ALL RIGHT?
THAT'S THE FIRST
THING TO REMEMBER.
THOSE ARE GEARS.
THEY JUST MESH
TOGETHER LIKE THAT.
NOW WE HAVE TWO GEARS HERE.
WE HAVE THE CRANKSHAFT GEAR.
IT'S THE DRIVE GEAR IN
THIS PARTICULAR CASE.
AND WE HAVE THE CAMSHAFT GEAR.
SO REMEMBER, THE CRANKSHAFT
DRIVES THE CAMSHAFT.
NOW WHAT'S ANOTHER THING YOU
NOTICE ABOUT THESE GEARS
IS THE SIZE.
THE CRANK GEAR IS HALF
THE SIZE OF THE CAM GEAR.
THE CRANK GEAR HAS 21 TEETH.
THE CAM GEAR HAS 42 TEETH.
WHAT'S THAT GOING TO TELL YOU?
WELL, IT'S GOING TO TELL ME
THAT THEY'RE GOING TO RUN AT -
THAT THE BIG GEAR IS GOING
TO RUN AT HALF THE SPEED.
LET ME PROVE IT TO YOU.
SEE I HAVE A DOT ON THE CRANK
GEAR AND I HAVE A RED MARK ON
THE CAM GEAR.
AS I TURN THEM OVER -- NOW
WATCH WHAT HAPPENS HERE.
AS I TURN THEM
OVER... ALL RIGHT.
TURN THEM AROUND.
THE CRANK GEAR HAS
TURNED AROUND ONCE.
NOTICE IT'S BACK.
AND THE CAM GEAR'S
ONLY TURNED HALF A TURN.
AND I KEEP GOING, GOING.
THERE.
AT THAT POINT THE CRANK GEAR
HAS TURNED TWO FULL TURNS
AND THE CAMSHAFT GEAR
HAS ONLY MADE ONE TURN.
OKAY, SO WHAT THAT TELLS ME IS
THAT THE CRANK GEAR IS GOING
TO GO TWICE AS FAST
AS THE CAMSHAFT GEAR.
OKAY, THAT'S GOOD.
I THINK EVERYBODY
UNDERSTANDS THAT.

Lorraine says OKAY.
I HAVE THREE QUESTIONS FOR
YOU, THE FIRST BEING,
WHAT'S THE DRIVER GEAR?
WHAT DID HE MEAN
BY DRIVER GEAR?
IF YOU CAN CALL ME
AND LET ME KNOW THAT.
I WILL TAKE YOUR CALL.
WHAT IS MEANT BY DRIVER GEAR?
I HAVE SOMEONE FROM SOUTHWOOD
PARK, I BELIEVE, SO IF YOUR
PHONE'S RINGING,
LIFT IT UP PLEASE.
HI.

The caller says THE DRIVER GEAR IS THE
GEAR THAT TURNS THE DRIVEN.

Lorraine says PERFECT.
PLEASE STAY ON THE LINE.
SO YOU'RE SAYING THE DRIVER
GEAR... SAY THAT AGAIN.

The caller says DRIVES THE DRIVEN.

Lorraine says DRIVES THE DRIVEN.
EXCELLENT.
AND DO YOU REMEMBER HOW MANY
TEETH THE DRIVER GEAR HAD?

The caller says 21.

Lorraine says 21, YES.
21 TEETH.
AND HOW MANY TEETH
DID THE DRIVEN HAVE?

The caller says 42.

Lorraine says 42.
EXCELLENT.
AND YOUR NAME IS...?

The caller says KELSEY.

Lorraine says THANKS, KELSEY.
AND I'M GOING TO TRY SOMEONE
HERE FROM St. JOHN BREBEUF
WHERE WHAT WAS THE
GEAR RATIO SHOWN?
HI.

The caller says HI.

Lorraine says DO YOU REMEMBER
THE GEAR RATIO?

The caller says WHAT?
TWO TO ONE.

Lorraine says YES.
YOU'RE SAYING TWO TO ONE.
AND THAT'S CORRECT.
WHAT DOES THAT
MEAN, TWO TO ONE?
DO YOU REMEMBER?

The caller says NO.

She draws two adjacent circles, one larger than the other.

Lorraine says OKAY, THAT'S ALL RIGHT.
THAT'S WHAT THIS WHOLE
LESSON WILL BE ABOUT.
SO TWO TO ONE, WHAT THEY'RE
SAYING IS IF THE DRIVER GEAR
BEING HALF THE SIZE OF THE
DRIVEN -- LET'S PRETEND IT'S
APPROXIMATELY LIKE THAT, TWO
TO ONE MEANING THIS ONE'S
GOING TO TURN TWO TIMES WHILE
THIS ONE TURNS ONLY ONCE.
DOES THAT MAKE SENSE?

The caller says YEAH.

Lorraine says GREAT, THANKS.
AND ONE MORE QUESTION AND I
WILL TRY SOMEONE ELSE FROM
SAINT JOHN BREBEUF.

The caller says HELLO.

Lorraine says HI.
DO YOU KNOW WHAT TYPES OF
GEARS HE WAS TALKING ABOUT?

The caller says A SMALL GEAR AND A BIG GEAR.

Lorraine says OKAY.
SMALL, BIG.
BECAUSE THEY WERE WITH A SMALL
ENGINE, HE WAS CALLING THEM
THE CRANKSHAFT GEAR AND THE
CAMSHAFT GEAR BECAUSE THEY
WERE ON PARTICULAR
PARTS OF THE ENGINE.
BUT FOR US, WHEN THEY LOOK
LIKE THAT, WE'RE GOING TO CALL
THEM SPUR GEARS, BECAUSE I'M
GOING TO BE TALKING ABOUT THAT
THROUGHOUT THE LESSON.
AND THE GEARS THAT
WE'RE USING IN OUR KIT,
THESE ARE SPUR GEARS.
OKAY?
THAT'S THE ONES
WITH THE TEETH.
THANKS.
ALL RIGHT.
AT THIS POINT, WE'RE GOING
TO BEGIN THE LESSON WHERE I
EXPLAIN TO YOU WHAT IS
A RATIO AND HOW TO TELL
DIFFERENT TYPES OF RATIOS.
CAN ANYONE JUST GIVE ME THE
GENERAL DEFINITION OF A RATIO?
OKAY.
I'LL LET YOU HAVE A FEW
MINUTES TO TRY THAT ONE OUT.
WE'VE ALREADY TALKED A
LITTLE BIT ABOUT RATIOS.
SO WHAT WOULD BE A
GENERAL DEFINITION?
AND WE HAVE SOMEONE
FROM SAINT CHARLES.
HELLO.
IF YOUR PHONE IS RINGING AT
SAINT CHARLES, IF YOU CAN
LIFT IT UP.

The caller says OH, DAMN.

Lorraine says OKAY.
PUTTING YOU UNDER
PRESSURE HERE.
CAN YOU COME UP WITH
A DEFINITION FOR RATIO?

The caller says WHAT'S THE
DEFINITION OF A RATIO?
I DON'T REMEMBER.

Lorraine says YOU DON'T REMEMBER.
WELL, NOW I WILL
REFRESH YOUR MEMORY.
HOW'S THAT?
IF WE LOOK AT THE SCREEN
HERE -- THANKS ANYWAY.
WE HAVE A COMPARISON OF
TWO OR MORE QUANTITIES
WITH THE SAME UNITS.
NOW WHAT DOES THAT ALL MEAN?
IT'S SAYING TWO OR
MORE QUANTITIES.
SO, FOR INSTANCE, IT
HAS TO BE SAME UNITS.
IF YOU'RE GOING TO COMPARE
SOMEONE'S TEETH WITH ANOTHER
PERSON'S TEETH, WELL, YOU
OBVIOUSLY HAVE TO DO TEETH AND
TEETH, THE SAME UNITS.
YOU WOULDN'T COMPARE THEIR
EYES WITH SOMEONE ELSE'S TEETH.
OR IF YOU WERE TO HAVE A RATIO
OF GEARS, FOR INSTANCE, YOU'RE
EITHER GOING TO TALK ABOUT
THE UNITS BEING THE AMOUNT OF
TEETH TO THE AMOUNT OF TEETH,
OR YOU COULD TALK ABOUT THE
AMOUNT OF ROTATIONS TO
THE AMOUNT OF ROTATIONS.
YOU'LL NEVER SEE A PARTICULAR
RATIO WHERE YOU'RE COMPARING
THE TEETH OF A GEAR
WITH THE RATIO --
TO MAKE IT A RATIO
AT THIS POINT, OKAY?
SO GIVE YOU AN
EXAMPLE OF THAT.
IF WE'RE TALKING ABOUT THE
TEETH RATIO OF GEARS, WE HAVE
TO COMPARE TEETH WITH TEETH.
SO I'LL TAKE MY PICTURE OUT OF
THERE AND WE'RE GOING TO TALK
ABOUT THE DRIVER
AND THE DRIVEN.
AND AS WAS MENTIONED, THE
DRIVER DRIVES THE DRIVEN GEAR.
AND AN EXAMPLE OF THAT, WE
HAVE THE 45 TEETH GEAR WITH
THE 15 TEETH GEAR, AND IF YOU
HAVE THAT IN FRONT OF YOU,
IT MIGHT HELP YOU
VISUALIZE, OKAY.
NOW, THE TEETH RATIO IN THIS
CASE WOULD BE 45-TO-15.
CAN ANYBODY CALL IN AND TELL
ME HOW CAN YOU REDUCE THIS
RATIO, 45-TO-15?
AND I HAVE SOMEONE FROM
SAINT CHARLES CALLING IN.
HELLO.

The caller says HI.
YOU WOULD FIND A COMMON
DENOMINATOR BETWEEN THEM.

Lorraine says OKAY, AND WHAT WOULD THAT BE?

The caller says FIVE.

Lorraine says OKAY.
CAN YOU GO EVEN SMALLER?
IF WE SAY FIVE --
LET'S GO OVER HERE.
IT WAS 45-TO-15.
NOW HOW ARE YOU
GOING TO DO FIVE?

The caller says PARDON ME?

Lorraine says HOW WOULD YOU PUT FIVE
INTO THESE TWO NUMBERS?

The caller says YOU WOULD -- HOW MUCH
IT TAKES TO GET INTO FIVE,
YOU WOULD DIVIDE IT BY THAT.

Lorraine says OKAY, AND GIVE
ME AN ANSWER THEN.

The caller says 9 AND 3.

Lorraine says AND CAN YOU REDUCE
IT EVEN FURTHER?

The caller says YES.
YES, ONE-THIRD
AND THREE-THIRDS.

Lorraine says THAT'S RIGHT, BECAUSE THREE
GOES INTO NINE THREE TIMES
AND THEREFORE THREE
GOES INTO THREE ONCE.
OKAY.
SO, ACTUALLY, THIS CAN BE
REDUCED AS FAR DOWN HERE AS
3-TO-1.
THEREFORE 15 DOES GO
INTO 45 THREE TIMES.
EXCELLENT.
THANK YOU.

The caller says YOU'RE WELCOME.

Lorraine says SO IF WE LOOK BACK AT OUR
SCREEN OVER HERE, AS WE KNOW,
WE'RE SAYING THE TEETH
RATIO BEING 45-TO-15.
WELL, LET'S SEE.
THE REDUCTION WOULD
BE THREE TO ONE.
WELL, WHAT DOES THAT MEAN?

She takes the vehicle frame.

Lorraine says WE'RE SAYING WE HAVE A
45 TOOTH WITH A 15 TOOTH.
SO THERE'S 45 TEETH AND
THEN THERE'S 15 TEETH.
SO WE'RE JUST COUNTING THE
AMOUNT OF TEETH AND HOW WE PUT
IT INTO A RATIO.
SO THERE'S 45-TO-15, AND
THEN WE COULD REDUCE IT TO --
IT'S ACTUALLY 3-TO-1.
AND THAT WE'LL EXPLAIN
A LITTLE BIT FURTHER.
IF WE LOOK TO
OUR SCREEN AGAIN.
IF WE'RE TALKING ABOUT A GEAR
RATIO NOW, WE HAVE A DRIVER
ROTATIONS TO THE
DRIVEN ROTATIONS.
BEFORE IT WAS A TEETH RATIO,
SO IT WAS TEETH TO TEETH.
NOW WE HAVE A GEAR RATIO
WHERE IT'S THE ROTATIONS
TO THE ROTATIONS.
AGAIN, WE'LL TALK ABOUT THE 45
TEETH TO THE 15 TEETH GEAR.
NOW THE 45 TEETH, AS WE
CAN SEE HERE, WILL BE
THE DRIVER GEAR.
AS WAS MENTIONED EARLIER, ONCE
AGAIN, IT DRIVES THE DRIVEN.
SO THIS IS YOUR DRIVER AND
THIS IS THE DRIVEN, OKAY?
AND IF WE WERE TO COMPARE THE
ROTATIONS, WHAT DO YOU THINK?
IF YOU CAN CALL IN.
HOW MANY ROTATIONS DO YOU
THINK IT WILL TAKE THIS ONE
IN RELATION TO THE
SMALLER GEAR HERE?
WE CAN EVEN LOOK.
IF WE BRING IT UP JUST
A TAD CLOSER LIKE THIS.
AND WE LOOK AT THE TWO ARROWS.
I PUT THAT ON PURPOSE SO
THERE'S - I'LL TURN MY DRIVER
GEAR LIKE THIS, AND WHEN IT
COMES BACK TO THE ARROW, SEE
HOW MANY TIMES THIS
ONE HAS TURNED.
OKAY, SO SEE THE ARROW?
AND GO... IT WENT ONCE.
WELL, THIS ONE STILL
HASN'T DONE ONE YET.
IT WENT TWICE.
AND NOW IT'S TURNING AGAIN.
THREE TIMES.
SO HOW MANY TIMES DID THIS ONE
TURN, THE 45 TOOTH, AND HOW
MANY TIMES THE 15?
LET'S SEE HERE IF YOU CAN
COME UP WITH AN ANSWER.
HELLO.
VICKY, FROM JACK MINER, IF YOU
CAN LIFT UP YOUR PHONE, PLEASE.
HI.
SO DID YOU NOTICE HOW MANY
TIMES THE 45 TOOTH GEAR
ROTATED AND HOW MANY TIMES
THE 15 TOOTH ROTATED?

Vicky says 45 ROTATED ONCE AND THE
15 ROTATED THREE TIMES.

Lorraine says OKAY, EXCELLENT.
SO IF WE LOOK BACK AT OUR
SCREEN OVER HERE, WE'RE SAYING
WE HAD THE 45 TEETH TO THE 15,
AND AS VICKY MENTIONED, YES,
IT'S A GEAR RATIO OF 1-TO-3,
BECAUSE THE 45 TOOTH ONLY
WENT ONCE AND THE 15 TOOTH
HAD TO GO AROUND THREE TIMES.
OKAY.
NOW WHAT'S INTERESTING IS WHEN
WE'RE COMPARING THE TEETH TO
TEETH WE HAD -- WHEN
WE THINK OF OUR 45-TO-15,
IT WAS A RATIO OF 3-TO-1
AND YET IF WE'RE TALKING ABOUT
THE ROTATIONS, IT'S REVERSED.
IT'S 1-TO-3.
NOW TO REINFORCE THAT JUST
A BIT, LET'S SEE IF YOU CAN
ANSWER A FEW QUESTIONS
HERE BY LOOKING AT A SHEET
THAT'S IN YOUR KIT.
AND YOUR TEACHER MAY HAVE
GIVEN IT TO YOU AT THIS POINT --
WHICH LOOKS LIKE THIS.

She shows a slate with a 7 column table.

Lorraine says IT'S CALLED GEAR RATIO
RECORDING TABLE.
AND WE'LL JUST GO OVER A
FEW TO MAKE SURE YOU'RE
UNDERSTANDING THIS CONCEPT.
IT SAYS -- AND IT'S NOT THAT
BIG SO I'LL BRING IT OUT A TAD,
LIKE THAT.
WHERE THEY'RE TALKING ABOUT
TEETH ON DRIVEN GEAR.
WELL, WE'VE SEEN ALREADY THE
15, AND TEETH ON DRIVEN GEAR.
THIS WAS THE DRIVER.
THIS IS THE DRIVEN.
IT'S 45.
SO THEY'RE REVERSING IT.
THEY'RE SAYING 15-TO-45.
NOW THE LITTLE ONE
IS THE DRIVER GEAR.
IT SAYS TEETH RATIO.
WHAT DO THEY MEAN BY
TEETH RATIO AGAIN?
WHEN WE THINK OF THE AMOUNT OF
TEETH, WHAT WOULD BE THE RATIO?
HELLO.
SAINT JOHN.

The caller says YES.

Lorraine says HI.
SO WHAT WOULD BE YOUR TEETH
RATIO IF YOU'RE THINKING OF
THE DRIVER BEING THE SMALLER
ONE AND THE DRIVEN BEING THE
MEDIUM ONE?

The caller says 1-TO-3.

Lorraine says OKAY, 1-TO-3.
AS WE CAN SEE ON YOUR SCREEN,
BUT I'M GOING TO KEEP YOU ON.
WE HAVE 15-TO-45 AND, YES, IF
YOU REDUCE IT, IT'S 1-TO-3.
HOW ABOUT THE ROTATIONS?
HOW MANY TIMES DO YOU THINK THE
LITTLE FELLOW HERE WILL ROTATE?
WE'VE SEEN IT ALREADY REVERSED,
BUT HOW ABOUT THIS WAY?

The caller says 3.

Lorraine says 3.
AND WE KNOW THAT ALREADY
BECAUSE IT'S ON THE PAGE.
HOW ABOUT THE 45 TOOTH?

The caller says 1.

Lorraine says AND, FINALLY, IF WE WERE
TO DO THE GEAR RATIO,
WHAT WOULD IT BE?

The caller says 3-TO-1.

Lorraine says OKAY.
WELL, THAT WAS A
LITTLE BIT EASY.
HOW ABOUT IF WE TRY HERE WITH
THE 15-TO-75, AND I'LL KEEP
YOU ON THE LINE
IF YOU DON'T MIND.
WHAT DO YOU THINK WILL
BE THE TEETH RATIO,
JUST THE LARGER AMOUNT,
FOR 15-AND-75?

The caller says 1-TO-4.

Lorraine says OKAY, BECAUSE YOU'RE
GOING EVEN QUICKER.
HOW ABOUT IF WE TRY JUST WHAT
YOU'RE SEEING HERE IN THE
LARGER AMOUNTS?
SEE HOW THIS ONE WE PUT
15 TO 45, THEN REDUCED IT?
WHAT'S THE...?

The caller says 15 TO 75.

Lorraine says YES.
YOU HAVE 15-TO-75, AND THEN
YOU'RE SAYING IT'S -- WHEN YOU
REDUCED IT, WHAT IS IT?

The caller says 1-TO-4.

Lorraine says SO YOU'RE SAYING 15
GOES INTO 75, FOUR TIMES.
TRY THAT.

The caller says FIVE.

Lorraine says YES, THAT'S RIGHT.
VERY GOOD.
SO IT'S 1-TO-5.
ALL WE'RE TALKING ABOUT,
ONCE AGAIN, IS THE TEETH.
NOW HOW MANY ROTATIONS DO YOU
THINK IT WILL TAKE FOR THE
DRIVER GEAR, THE
LITTLE ONE, TO ROTATE?

The caller says 5.

Lorraine says YEAH, VERY GOOD.
AND HOW MANY TIMES DO YOU
THINK FOR THE DRIVEN GEAR?

The caller says 1.

Lorraine says IS THE GEAR RATIO.

The caller says 5-TO-1.

Lorraine says 5-TO-1, EXCELLENT.
THANKS VERY MUCH.
AND LET'S TRY
ONE MORE PERSON.

The caller says HELLO.

Lorraine says HI.
I'M GOING TO GIVE YOU ONE THAT'S
A LITTLE MORE COMPLICATED.
DO YOU MIND?

The caller says NO.

Lorraine says OKAY, GOOD.
SO WE HAVE ONE HERE.
WHAT ARE YOU NOTICING?
WHAT ARE THE SIZES?

She shows the vehicle frame with the gears again.

The caller says 75 AND 45.

Lorraine says OKAY.
AND WHERE DO YOU SEE
THAT ON MY SHEET HERE?

The caller says THE BOTTOM.

Lorraine says YES.
WE'RE LOOKING AT
THIS RIGHT OVER HERE.
OKAY, VERY GOOD.
NOW, WHAT IS THE TEETH RATIO?

He caller says 75-TO-45.

Lorraine says OKAY, CAN YOU REDUCE THAT?
IS THERE A NUMBER
THAT GOES INTO BOTH?

The caller says 5-TO-3.

Lorraine says OKAY.
SO YOU THINK
IT'S 5-TO-3.
NOW WHY ARE YOU
SAYING 5-TO-3?
WHAT ARE YOU
PUTTING IN THERE?
YOU'RE CORRECT, BUT WHAT'S
THE NUMBER YOU'RE PUTTING
IN THERE?
YOU'RE CORRECT.

The caller says 15.

Lorraine says YEAH, 15 GOES
INTO 75 FIVE TIMES.
AND YOU CAN REDUCE IT
GRADUALLY IF ONE CAN'T SEE IT.
AT LEAST YOU KNOW FIVE
AND THEN YOU REDUCE IT.
EXCELLENT.
NOW HOW MANY ROTATIONS -- IF WE
THINK OF 75 AND 45, OKAY...
LET ME GET THE
TWO ARROWS TOGETHER.
HOW MANY ROTATIONS IF THIS
IS YOUR DRIVEN GEAR AND
YOUR DRIVER GEAR?
HOW MANY DO YOU THINK?

The caller says 3-TO-5.

Lorraine says WELL, LET'S SEE.
CAN YOU COUNT EVERY TIME YOU
SEE THIS ARROW COMING BACK
AT THIS POINT, OKAY?

She turns the larger gear in the vehicle frame.

The caller says YUP.

Lorraine says SO...

The caller says 1.

Lorraine says OKAY, THANKS.
AND THEN IT'S COMING BACK.

The caller says 2.

Lorraine says AND THEN WHEN THEY
MEET AGAIN, WHAT IS IT?

The caller says 3.

Lorraine says THEY STILL HAVEN'T MET.

The caller says 4.

Lorraine says AND WHAT ARE WE NOTICING?

The caller says 5.

Lorraine says YEAH, 5.
HOW ABOUT THIS ONE?
DO YOU REMEMBER HOW
MANY TIMES IT MOVED?

She points at the larger gear.

Lorraine says LET'S TRY IT QUICKLY.
SO WE'RE GOING TO START HERE.
WHEN THE ARROW
TOUCHES OVER HERE.

The caller says 1... 2... 3...

Lorraine says SHOULD WE CONTINUE?

The caller says NO.

Lorraine says WHY?

The caller says BECAUSE THE TWO
ARROWS ARE TOGETHER.

Lorraine says OKAY, PERFECT.
SO IF WE GO BACK TO OUR SHEET
HERE, IF WE WERE TO WRITE DOWN
THE ROTATIONS OF THE DRIVER
GEAR, WHAT ARE THEY AGAIN?

The caller says 3-TO-5.

Lorraine says THAT'S RIGHT.
3-TO-5.
AND IF YOU WRITE THAT OUT IN A
RATIO IT WOULD LOOK LIKE THIS.
NOW, ARE WE NOTICING ANYTHING
AS FAR AS THE RATIO OF TEETH
TO THE RATIO OF THE GEARS?

The caller says IT'S REVERSED.

Lorraine says YEAH, THEY'RE REVERSED, OKAY.
SO IF YOU CAN VISUALIZE IT,
AND SEE IT, IT MAKES IT THAT
MUCH EASIER.
THANKS VERY MUCH
FOR YOUR CALLS.
NOW I'M GOING TO TEST ALL OF
YOU BY ASKING YOU A QUESTION
WHERE YOU REQUIRE YOUR PHONES.

Question 2 appears on screen. It reads “If the driver gear is 75 teeth and the driven gear 15 tenth, what is the teeth ratio? 1- 5 to 1; 2- 6 to 1; 3- 4 to 1 or 5- 1 to 5.”

Lorraine says BE CAREFUL.
WE'RE ASKING TEETH RATIO.
IF YOU HAVE IT IN FRONT OF
YOU, IT HELPS TO VISUALIZE IT.
OKAY, WE ALMOST HAVE
A HUNDRED PERCENT.

The results appear in a bar graph. 40 students pressed option 1, 1 student pressed option 2, 6 students pressed option 6 and 18 students pressed option 4.

Lorraine says IF WE LOOK AT OUR ANSWERS OVER
HERE, THE MAJORITY OF YOU FEEL
THAT IT IS 5-TO-1,
THE TEETH RATIO.
A FEW OF YOU ARE THINKING
IT IS 6-TO-1, SOME 4-TO-1,
AND SOME 1-TO-5.
NOW, ONE AND FOUR
ARE THE MOST POPULAR.
LET'S HAVE A LOOK
AT THE 75 AND 15.
IF WE GO OVER HERE, REMEMBER
WE TALKED ABOUT 75 AND 15.
PICTURE THE LARGE GEAR WHICH
IS 75 AND 15 WOULD BE YOUR
REALLY TEENIE-WEENIE ONE THERE.
THIS LITTLE GEAR.

OKAY.
NOW, WHAT DO YOU THINK -- AND
IF YOU CAN CALL IN, JUST TO
VERIFY, WHY IS IT YOU FEEL IT
MIGHT BE 1-TO-5 OR 5-TO-1?
SO WE'RE TALKING
ABOUT THE 75 AND 15.

She goes back to the ratio table.

She says WE HAVE SOMEONE
FROM SOUTHWOOD PARK.
WE'VE ALREADY
DONE THE REVERSE.
SO IF WE THINK OF THE LARGE
ONE WITH THE LITTLE LITTLE ONE.
HELLO.

The caller says HI.

Lorraine says SO WHAT DO YOU THINK WOULD BE
THE TEETH RATIO OF 75-TO-15?

The caller says 5-TO-1.

Lorraine says OKAY.
WELL, EVEN IF WE PUT IT DOWN
THE WAY IT LOOKS, 75-TO-15,
YOU'RE REDUCING IT -- BECAUSE
WHAT NUMBER ARE YOU PUTTING
IN THERE?

The caller says 15.

Lorraine says OKAY, SO YOU'RE
SAYING IT'S 5-TO-1.
AND YOU ARE CORRECT.
SO IF WE GO BACK TO OUR
QUESTION, IT WAS NUMBER ONE,
5-TO-1.
SO THOSE OF YOU WHO DID
PUT NUMBER ONE, EXCELLENT.
THOSE OF YOU WHO PUT NUMBER
FOUR, YOU'RE GETTING THEM A
LITTLE BIT MIXED UP, SO IT
WOULD BE A GOOD REFRESHER TO
GO OVER THAT ON YOUR OWN AS
WELL, OR WITH YOUR TEACHER.
AND AT THIS POINT I DO
HAVE ANOTHER QUESTION.
SO I WOULD LIKE YOU TO HAVE
YOUR PHONES ONCE AGAIN.
AND HERE IT IS:

Question 3 appears on screen. It reads “If the driver gear is 75 teeth and the driven gear 15 teeth, what is the gear ratio? 1- 6 to 1; 2- 1 to 5; 3- 4 to 1 and 4- 3 to 1.”

Lorraine says NOT THE TEETH RATIO,
BUT THE GEAR RATIO.
NOW WE'RE TALKING ROTATIONS.
OKAY, WE ALMOST HAVE A
HUNDRED PERCENT ANSWERING.

The results appear in a bar graph. 4 students pressed option 1, 51 students pressed option 2, 1 student pressed option 3 and 7 students pressed option 4.

Lorraine says LET'S GO TO OUR BAR GRAPH.
WELL, WE CAN SEE THE MAJORITY
OF YOU FEEL IT IS 1-TO-5
SOME OF YOU STILL AREN'T TOO
SURE, BUT LET'S LOOK AT OUR
CAMERA ONCE AGAIN.
WE SAID WE'VE GOT THE 75, THE
LARGE GEAR WITH THE LITTLE ONE.
SO MAYBE WE CAN EVEN DRAW
IT LIKE THAT, WHERE YOU'RE
PICTURING A LARGE GEAR
WITH A LITTLE GEAR.

She draws a large circle around the 75 and a smaller one around the 15.

Lorraine says OKAY, THIS WAS THE TEETH RATIO,
75 TO 15, WHICH WAS REDUCED.
NOW WE'RE TALKING
ABOUT ROTATIONS.
WHO CAN ANSWER WHY
THEY PUT 1-TO-5?
WHY IS IT YOU PUT 1-TO-5?
I HAVE SOMEONE
FROM SAINT CHARLES.
IF YOUR PHONE IS RINGING.

The caller says HI.

Lorraine says HERE, WITH THE 75-TO-15, THE
LARGE WITH THE LITTLE, HOW
MANY ROTATIONS DO YOU THINK
THIS BIG FELLOW WILL DO HERE
TO THIS LITTLE ONE?

The caller says 1-TO-5.

Lorraine says YEAH.
WHY ARE SAYING 1-TO-5?

The caller says BECAUSE IT'S REVERSED.

Lorraine says YEAH, IT'S REVERSED.
AND IF YOU VISUALISE IT,
OBVIOUSLY THE BIG ONE'S GOING
TO TAKE ONE ROTATION WHILE
THIS LITTLE ONE WILL PROBABLY
HAVE TO MAKE FIVE BY THE
TIME THIS ONE DOES ONE.
CORRECT?

The caller says CORRECT.

Lorraine says YES.
SO THEN THAT'S HOW WE WOULD
WRITE IT, AND IF WE GO BACK TO
OUR AREL QUESTION, THE
MAJORITY OF YOU DID ANSWER THAT.
SO EXCELLENT.
GOOD WORK.
NOW I'VE BROUGHT IN A FEW
PROPS THAT WE OFTEN SEE --
I GUESS PROBABLY MOSTLY IN THE
KITCHEN, BUT THEY CAN BE SEEN
IN OTHER AREAS.
I HAVE HERE A
ONE-LEGGED EGG BEATER.
OKAY.
NOW, THERE ARE A FEW GEARS
HERE THAT I WILL SHOW TO YOU.
WITH THIS HANDLE -- AND YOU
CAN CALL IN AND LET ME KNOW --
HERE'S A GEAR AND THERE'S
ANOTHER LITTLE ONE HERE, AND
AS I TURN, WHICH ONE DO YOU
THINK IS THE DRIVER AND WHICH
ONE'S THE DRIVEN?

She rotates the larger gear with the handle.

Lorraine says IF YOU CAN CALL IN.
WHICH ONE DO YOU
THINK IS THE DRIVER
AND WHICH ONE IS THE DRIVEN?
AND IF I SHOW YOU THAT IN
FULL, LOOK WHAT HAPPENS
WHEN I ROTATE IT.
AS I'M ROTATING ONLY ONCE,
WHAT'S HAPPENING DOWN BELOW?
HELLO.
HI.

The caller says HI.

Lorraine says CAN YOU LET US KNOW WHICH GEAR
IS THE DRIVER AND WHICH ONE'S
THE DRIVEN?

The caller says THE DRIVER IS THE BIG ONE AND
THE DRIVEN IS THE SMALL ONE.

Lorraine says THAT'S RIGHT, EXACTLY.
THE DRIVER IS THE BIG ONE --
AND LET'S WRITE THAT DOWN.
WE HAVE THE DRIVER -- AND
STAY ON THE LINE, PLEASE.
I'M GOING TO LET YOU KNOW THAT
THIS DRIVER OVER HERE HAS
APPROXIMATELY 60 TEETH, OKAY?
AND I'M GOING TO LET YOU KNOW
THAT THE DRIVEN HAS 12 TEETH.
ALL RIGHT.
SO WHAT DO YOU THINK
IS THE TEETH RATIO?
NOW WE'RE TALKING 60
TEETH TO 12 TEETH.
SO WHAT'S THE RATIO?

The caller says SIX BY TWO?

Lorraine says OKAY.
WHAT ARE YOU DOING HERE?

The caller says NO, TEN BY SIX
OR SOMETHING.

Lorraine says OKAY.
WELL, YOU'RE REDUCING IT.
WHAT ARE YOU DOING HERE?
YOU'RE SAYING IT'S
60 BY 12, RIGHT?
60-TO-12, THE RATIO?
HOW ARE YOU REDUCING THAT?
WHAT NUMBER GOES INTO BOTH?

The caller says 6.

Lorraine says OKAY.
SO 6 -- WHAT DOES IT DO?

The caller says 10.

Lorraine says OKAY, KEEP GOING.

The caller says AND 6, RIGHT?

Lorraine says 6 INTO THIS GOES...?

The caller says 2.

Lorraine says 2, GOOD.
NOW CAN YOU REDUCE IT FURTHER?

The caller says 5... AND 1.

Lorraine says OKAY.
SO THIS IS THE TEETH RATIO.
OKAY.
SO THAT'S HOW MANY
TEETH TO THIS TEETH.
NOW WE'RE GOING TO TALK
ABOUT THE GEAR RATIO.
THAT'S ROTATIONS.
SO HOW MANY ROTATIONS --
IF YOU THINK OF THIS ONE.
HOW MANY ROTATIONS DO YOU
THINK THE BIG GEAR WILL TAKE,
AND THE HOW MANY DO YOU THINK
THE LITTLE ONE WILL TAKE?

The caller says 5-TO-1 OR...
NO, 1-TO-5.

Lorraine says SO YOU'RE SAYING
THIS ONE...
OKAY, SO YOU'RE SAYING
THE LARGE GEAR --

The caller says WILL GO AROUND ONCE AND THEN
THE SMALL ONE WILL GO AROUND
FIVE TIMES.

Lorraine says THAT'S RIGHT.
AND IF YOU CAN VISUALIZE
THAT, THAT HELPS.
SO IN OTHER WORDS, I'M DRIVING
THIS ONE AND TURNING IT ONCE.
AND GUESS WHAT
HAPPENS DOWN HERE?
BECAUSE THE LITTLE ONE'S
HAVING AN EFFECT ON MY BEATER.
SO I TURN THIS ONCE, AND HOW
MANY TIMES DO YOU THINK THE
BEATER WILL TURN THEN?

The caller says FIVE TIMES.

Lorraine says YEAH.
AND WHY DO YOU
THINK THAT'S GREAT?
DO YOU THINK I WOULD NORMALLY
WANT TO TURN IT FIVE TIMES
FOR THIS TO TURN ONCE?

The caller says NO.

Lorraine says NO, THAT'S RIGHT.
I WANT TO TAKE LESS EFFORT.
SO I USE THE LARGER GEAR
TO TURN ONCE AND THIS WILL
ACTUALLY TURN FIVE TIMES.
OKAY.

The caller says BYE, LADY.

BYE.
NOW IMPORTANT HERE AS WELL
IS WHEN YOU HAVE A GEAR LIKE
THIS, WHERE IT'S FLAT -- A FLAT
CIRCULAR GEAR WITH A SPUR
GEAR, WE CALL THAT -- AND YOU
MIGHT WANT TO WRITE THIS DOWN
BECAUSE IT'S VERY
IMPORTANT TO KNOW.
IT'S CALLED A RACK
AND PINION GEARS.
RACK AND PINION.
AND THAT'S WITH A...
IT'S JUST GOOD TO KNOW.
YOU PEOPLE ARE USING JUST THE
SPUR GEARS, BUT WHEN IT'S A
FLAT CIRCULAR WITH THE ROUNDED
GEAR, YOU CALL THIS THE RACK
AND THIS THE PINION.

She signals the larger gear as the rack and the smaller one as the pinion.

Lorraine says OKAY.
AND VERY QUICKLY, I'M GOING
TO JUST SHOW YOU SOME OTHER
OBJECTS THAT ARE COMMON TO US
WHERE WE HAVE A BOTTLE OPENER.
AND, AGAIN, YOU HAVE THE RACK
AND PINION, BECAUSE IF YOU
LOOK UP CLOSELY HERE, YOU HAVE
THE PINION AND THE RACK IS
THIS PART, OKAY.
SO AS YOU'RE ROTATING IT LIKE
THIS, YOU GET THE RACK AND
PINION GEARS IN EFFECT, OKAY.
AND ONE MORE.
WE LOOK HERE AT THE CAN OPENER,
WHICH IS QUITE INTERESTING.
UP CLOSE, YOU HAVE THE TWO
GEARS, AND THIS GEAR TURNS
THE CAN, AND THEN THIS ONE
TURNS THE SHARPENER, OKAY.
IT'S THE CUTTER.
SO THIS GEAR, IF WE DIDN'T
HAVE IT THERE, WHAT WOULD
HAPPEN IS IT WOULD NOT ROTATE.
THIS IS THE CUTTER.
IT WOULD NOT ROTATE AND
THEREFORE WE'D ALWAYS BE
CUTTING AT THE ONE
POINT OF THE BLADE HERE.
AND THIS IS WHY THEY CHOOSE
TO PUT ANOTHER GEAR, SO IT
ROTATES AT THE SAME TIME AND
THEREFORE YOU'RE USING THE
FULL CIRCULAR PART
OF THE CUTTER.
OKAY.
SO YOU MAY WANT TO LOOK AT
THAT IN MORE DETAIL WHEN
YOU'RE AT HOME, OKAY.
YOU DID VERY WELL
TODAY, BY THE WAY.
AND JUST VERY BRIEFLY, IF YOU
SEE IN YOUR KITS FOR THE WORLD
IN MOTION, THERE IS THE DESIGN
LOG, WHERE YOU BECOME THE
ENGINEERS, AND IT
LOOKS LIKE THIS.

She shows a slate with the caption “Design Log” and a graph representing a pegboard.

Lorraine says AND WHAT HAPPENS IS THIS IS
YOUR ACTUAL VEHICLE FRAME.
SEE ALL THE HOLES THERE
IN THE VEHICLE FRAME?
THAT'S WHAT THESE
ARE, THE DOTS, THE HOLES.
SO YOU CAN ACTUALLY -- IF WE
WERE TO DO A GEAR RATIO OF
15-TO-75, YOU CAN DRAW
THE 15 AND THEN DRAW THE 75
AND MAKE YOUR OBSERVATIONS.
SAY WE NOTICED THE TEETH RATIO
IS SO-AND-SO, AND THE GEAR
RATIO IS SO-AND-SO.
IT'S EXACTLY WHAT AN ENGINEER
WOULD DO, MAYBE IN A LITTLE
MORE DETAIL THAN THAT, BUT IT
GETS YOU STARTED TO APPRECIATE
THE OBSERVATIONS
THAT YOU WERE MAKING.
OKAY.
QUICKLY, TO LET YOU KNOW
THAT I WILL BE GIVING YOU
YOUR HOMEWORK.
BUT BEFORE THAT, IF YOU HAVE A
LOG FOLDER, WHICH YOU SHOULD
HAVE GOTTEN STARTED LAST WEEK.
IF YOU DIDN'T, ONCE AGAIN, PUT
ALL THIS INFORMATION INTO YOUR
LOG FOLDERS SO YOU
CAN REFER TO IT LATER.
THAT WE'LL FOLLOW
UP WITH HOMEWORK.
AND WHAT YOUR HOMEWORK LOOKS
LIKE IS THIS ALSO, SO IF YOU
CAN WRITE IT DOWN, PLEASE.

A slate appears with the caption “Homework. 1- Gear rotation recording table. 2- Gear Ratio recording Table and 3- Software: How Things Work.”

Lorraine says AND THAT LOOKS LIKE THIS, IF
YOU HAVEN'T DONE IT ALREADY
WITH YOUR CLASS.

She shows a slate with a 5 column-table with the “Teeth on Driver Gear” and the “Teeth on Driven Gear” columns filled with numbers.

Lorraine says IT'S A FORM LIKE THIS THAT
YOUR TEACHER CAN GIVE YOU,
AND IT'S IN THE KIT.
AND I WANT YOU TO TRY AND
FIGURE OUT ALL THE TURNS OF
THE DRIVER GEAR AND TURNS OF
THE DRIVEN GEAR, AND YOU CAN
EVEN DO A DRAWING, JUST LIKE
YOU DID IN YOUR DESIGN LOG.
OKAY.
AND, AS WELL, I WOULD LIKE YOU
TO CONTINUE ON WITH THE GEAR
ROTATION RECORDING TABLE THAT
IS BLANK, SO YOU CAN ADD YOUR
OWN ROTATION, AND
TRY IT ON YOUR KITS.
SEE HOW EFFECTIVE
THEY ARE, OKAY.
AND THE NEXT THING
YOU WILL BE DOING,
GEAR RATIO RECORDING TABLE.
NOW YOU'RE DOING THE RATIOS
OF THE GEARS, WHICH IS THE
ROTATION ONCE AGAIN.
FOLLOWED BY SOME SOFTWARE.
IF YOU HAVE HOW THINGS WORK I
WOULD REALLY APPRECIATE IF YOU
COULD GO THROUGH THE SOFTWARE.
IT DOES LOOK LIKE THIS:

He shows a case with the software by David Macaulay. The letters in the title “The way things work” are mechanical objects such as corkscrew.

Lorraine says THE WAY THINGS WORK.
IT'S ABSOLUTELY FANTASTIC.
NEXT WEEK WE'RE GOING TO GO
THROUGH SECTIONS OF IT, SO IF
YOU CAN LOOK AT IT, AND GO
INTO THE SECTION OF GEARS.
GO INTO THE INDEX, WHICH
LOOKS SIMILARLY TO THIS.

She shows a printed screenshot of the software interface in the section “Principles of Science. Gears and Belts.”

Lorraine says ONCE YOU GET YOUR MAIN -- ONCE
YOU GET INTO THE SOFTWARE,
THERE'S A WHOLE SECTION
HERE WITH INFORMATION.
IF YOU CAN GO WHERE
IT SAYS INDEX, OKAY.
PRESS CLICK ONTO THAT, AND
THEN YOU CAN CHOOSE GEARS.
JUST PUNCH IN THESE
NUMBERS THERE, G-E-A-R-S,
AND IT'S INCREDIBLE
THE INFORMATION THAT
THEY WILL GIVE YOU.
SO ANYTHING THAT'S COLOURED,
YOU CAN PRESS ON IT.
THERE'S A LITTLE VIDEO.
IT'LL TALK TO YOU ABOUT IT.
AND IT'S A LOT OF FUN.
I CERTAINLY ENJOYED IT OVER
THE WEEKEND, AND VERY VISUAL.
THERE'S SOMEONE THAT TALKS TO
YOU AT TIMES, AND I'D LIKE
YOU TO GO THROUGH THAT.
NOW THAT'S NOT COMPLETE.
ONCE YOU GO INTO THE INDEX,
GEARS AND BELTS, HAVE A LOOK
AT GEARS TO INCREASE SPEED.
UNDERSTAND THAT, BECAUSE NEXT
WEEK WE'RE TALKING ABOUT
COMPOUND GEARS, AND YOU REALLY
MUST UNDERSTAND THE SIMPLE
GEARS BEFOREHAND.
AND THEN GEARS
TO REDUCE SPEED.
THIS SLATE OF THE HOMEWORK
WILL BE COMING BACK AT THE END
OF THE PERIOD, WHICH IS IN A
FEW MINUTES, AND WE'LL PLACE
THAT AGAIN IN CASE YOU HAVEN'T
HAD A CHANCE TO WRITE IT DOWN.
AS WELL, WE'LL PUT DOWN OUR
WEBSITE FOR TV ONTARIO, FOR
THE WORLD IN MOTION BECAUSE
THERE'S EXCELLENT SECTIONS
WHERE YOU CAN GO INTO THE
INTERNET, ABOUT GEARS, DESIGN
LOGS, AS WELL AS INFORMATION
ABOUT THE LAST TWO CLASSES.
OKAY?
AND WE HOPE YOU HAVE A NICE
AFTERNOON AND A NICE FEW DAYS,
AND WE'LL SEE YOU ON
THURSDAY FOR COMPOUND GEARS.
BYE-BYE.

A slate appears with the caption “Virtual Classroom WWW. www2.tvo.org/vclass.”

The homework slate appears again with the caption “Homework. 1- Gear rotation recording table. 2- Gear Ratio recording Table and 3- Software: How Things Work. A- Index: Gears and Belts; b- Gears to increase speed?; c- Gears to reduce speed?”

Another slate appears on screen. It reads “Please remember to log off! Pick up handset. Press number 7. Press 1 to confirm. Hang up handset. See you next time!”

Watch: Simple Gears - ST3