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PHYSICS NYA BICYCLE PROJECT

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Shaelyn Vasquez

on 16 November 2014

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Transcript of PHYSICS NYA BICYCLE PROJECT

Who invented the bicycle as we know it today ?

The shocking truth is ...
Under the umbrella of the velocipede came a new bicycle commonly known as the Penny-Farthing or High Bicycle.
Rover Safety Bicycle
John Kemp Starley was the English chap who is credited with pioneering the shape of our bicycle.


Now some people argue that Starley's addition of the was the best thing...
(but we're voting for the tires ourselves -
Pneumatic tires are much less bone-shaking and bottom bruising
)

just to set the record straight ...
The pneumatic tires were developed in 1887, by
John Boyd Dunlop
- founder of the Dunlop Pneumatic Tyre Co.
Note folks it's said DEVELOPED not invented.

SO....
NOBODY
PHYSICS NYA BICYCLE PROJECT
INTRO - PART I
By : Malaika Saint-Victor & Shaelyn Vasquez
NOBODY
actually
invented
the bicycle as we know it today
Impossible ?!?!
no, not impossible.
This mighty machine is a product of many years of
EVOLUTION
LET'S GO BACK IN TIME
The origins of the bicycle are buried in mystery. It is not possible to credit its invention to anyone. But it's clear that the early models of the modern bicycle were in use by the early 1800s.
- Early Models -
The walking machine
&
the velocipede
We must regard the great-granddaddy of the modern bicycle to be the German nobleman,
Baron Karl Drais Von Sauerbronn

The Draisine (or Draisienne) had two wheels and a wooden frame with a rotating handlebar attached, which permitted the front wheel to be turned.
This machine was powered by pushing your feet along the ground.


The Baron's invention became famous across Europe and England
Other inventors began to tinker with his design.
They added , and gave them fancy names like the hobby horse and dandy horse.



arm-rests
adjustable seats
In 1839 a Scottish blacksmith by the name of

came up with an ingenious way of making it possible for the Draisienne to be ridden with your feet


Guess how ladies and gentlemen?



That's right sir.

PEDALS!
Kirkpatrick Macmillan
OFF THE GROUND!
MACMILLAN'S VELOCIPEDE (1839)
Two decades later came the next big

of the bicycle.
This time it was a French man

EVOLUTION
Pierre Michaux & his son Earnest
Michaux Velocipede (1863)
In 1863 the Michauxs came up with the idea of attaching the pedals to a cranked arm, which would then engage the wheel.


By all accounts it was an incredibly uncomfortable bike.
The velocipede had a wooden frame and wooden wheels. Those wheels were then encased in iron ...

The front wheel was slightly higher than the back and the pedals were attached to the front wheel.
And, we must say the seat looks TINY.
GENIUS!!!
FRONT
This mighty machine is also known as the "Boneshaker" because of its tough ride
Michaux Velocipede (1963)
Lallement Velocipede (1962)
INTERESTING FACT
In 1862 Pierre Lallement took a dandy horse and modified it.
In his design he attached a transmission to the front-wheel hub. (even before the Michauxs came up with the idea)
The transmission was made up of a rotary crank device and pedals.
Lallement then travelled to Paris (and excuse the pun),
pedalled his invention about...
While he received some interest from the enterprising Olivier Brothers, he had no real success and he moved to the USA.
HIGH WHEEL
BICYCLE (1869)
In 1869,
Eugene Meyer
invented the classic
High Bicycle design
and fashioned the
wire-spoke tension wheel
.

Apparently
James Starley
LATER
added the
tangent spokes
and the
mounting step
to his famous bicycle named Ariel.
Surely you have all seen a Penny-Farthing before...
It has a great big wheel at the front and a tiny wheel at the back.
It was named - as you of course will have already deduced - after the British coins the Penny and ... you guessed it ... the Farthing

The Penny-Farthing was built with a large front wheel, essentially for purposes of .
It was, however, NOT renown for its safety.
In fact they had quite a reputation for being accident-prone. Which, ladies and gentlemen, creates a nice little segway for us into the introduction of the

SAFETY BICYCLE
SPEED
invented the bicycle...
IT EVOLVED.
MODERN DAY
The Rover Safety Bicycle was an success. It pretty much wiped out the old velocipede industry overnight.
WHY?
Well for a start it was much more
stable
then the old Penny-Farthing. It had two
smaller
,
similar-sized
wheels ...

(A great start already we'd say, ladies and gentlemen, wouldn't you?)

It was a rear wheel drive.
It had a diamond frame connecting the wheels.
The pedals were attached to a sprocket through gears and a chain.
AND the best thing

Drum roll please ...

TIRES. PNEUMATIC TIRES. Air-filled tires!!!

INSTANT
ROVER
SAFETY
BICYCLE
CHAIN
WOW! What a wrap for the little old bicycle, wouldn't you say, ladies and gents?

Of course nobody stopped tinkering with the Safety Bike.

Nothing is THAT perfect ...

Modifications were made. New features introduced.

The hand brake
The coaster brake
The variable drive gear
Adjustable handlebars
The free-wheel

And so the future shape of our modern bicycle began to emerge ...
like a butterfly from a chrysalis.
Ahh ... so poetic - and OK we'll admit just a little cliché'd...
Pedaling right along folks ...
click this video to see a quick minute of the overall evolution the bicycle (you'll enjoy it, i promise, it comes with catchy music too)
ADVANTAGES OF
EQUAL SIZED WHEELS
The fact that the wheels of a bicycle are equal, gives the cyclist more stability when he/she goes up the hill because is weight is evenly distributed.Therefore, having equal sized of wheel is more safe.
PEDALS
The bicycle pedals provides the link of the cyclist’s feet and the crank of the bicycle.The pedals are engaged by the muscular force of your feet. Subsequently, this force will be transmitted to the rear sprocket which engages the back wheel

The bicycle pedals provides the link of the cyclist’s feet and the crank of the bicycle.The pedals are engaged by the muscular force of your feet. Subsequently, this force will be transmitted to the rear gear and consequently be transmitted to the back wheel to put the bicycle in motion.The advantage of the pedals is that the pedals make you move in a constant speed according to the way you pedal. Comparing with the old bicycle, they would have to push themselves on the walking-machine constantly with their feet on the ground which makes it less efficient.
GEARS & A CHAIN
RUBBER TIRES
Pneumatic tires improved a rider's comfort
The
chain
transmits the rotary motion from one gear to the another. In the case of a bicycle, from the pedal gear, to the rear sprocket.
The
gears
contribute in a way for you to consistently turn the pedals at the same resistance whether you are going uphill or if you are pedaling on a regular flat surface.
Gears allows you to trade power for speed and the other way around when the riding conditions calls for it.
When you are going uphill it is better to choose the gears with a
low gear ratio
for the simple reason that you have more resistance and you drive against gravity.You will move slowly and you will pedal more but it is
easier
for you to go up the hill. When you are traveling on a flat surface and you are already in motion, you've overcome any starting resistance and the only components that affect your motion on the bicycle would be the rolling friction of the gear works and the friction between the tires and the road, so you can shift to a
higher gear
where you continue to pedal at the same pace but each stroke is translated into a
longer distance
because you're not fighting gravity.

The formula we developed
s
wheel
=
EXPERIMENTAL VERIFICATION
ΔƟ
front sprocket
*
r
front sprocket
______________________
r
rear sprocket
*
r
back wheel
how?
1. Calculate the theoretical distance that the back wheel makes according to the formula we've developed
2. Take the bicycle out and set the gears according to the gears you have used to for your calculations
3. Mark the back wheel's starting point
4. Perform one pedal stroke & mark the back wheel's endpoint
5. Measure the distance between the first and last mark (This is your experimental distance)
6.
Compare your experimental and theoretical distance values
(We have realized that this experimental verification isn't the most precised and ideal way to verify our formula due to the fact that the bicycle would've not been going in a straight line and our human's pedal stroke wasn't necessarily precised either)
theoretical (s) = 3.86m
experimental (s)= 3.42m
EQUAL SIZE WHEELS
PEDALS
GEARS & A CHAIN
RUBBER TIRES
The rubber of the tire is designed to resist/combat the cutting and abrasive wear of road contact and to protect the tire against puncture and loss of air
basically a solid rubber or cushion tire filled with compressed air has the capacity in itself to carry load or absorb shocks.
DRAISIENNE (1817)
IRON!!!
GEAR COMBINATIONS
ITS EASIER TO PEDAL ...
TRAVEL FURTHER...
Using gear ratios, we realize that the more teeth that the rear sprocket has, the easier it is to pedal.

The gear ratio formula stipulates that the number of teeth the pedal gear has on the rear sprocket gear is the number of pedal strokes per rear sprocket gear turn. So by having more teeth on rear sprocket gear, the more the number of pedal strokes decreases, making it easier to pedal.
WHY?
combo : smallest pedal gear with BIGGEST sprocket gear
The higher the gear the further the bike will travel for one complete pedal revolution. In low gear the bike will not travel as far. A high gear is one which has a high teeth number on the front gear with a low teeth number on the rear sprocket.
combo: Biggest pedal gear with the smallest sprocket gear
w
rear
*
r
rear
=
w
front
*
r
front
ΔƟ
___
Δt
*
r
rear
=
ΔƟ
front
_____
Δt
*
r
front
ΔƟ
wheel
*
r
rear
=
ΔƟ
front
*
r
front
ΔƟ
wheel
=
ΔƟ
front
*
r
front
_____________
r
rear
s
wheel
=
ΔƟ
front
*
r
front
____________
r
rear
*
r
back wheel
WHY?
Since the front gear has a higher number of teeth it will take more revolutions of the back sprocket which would lead to more turns of the back wheel making it move further.
Full transcript