By Alisa Kawashita
Problem
Deaths and Injuries Caused by CarCrashes
About 115 people die in a car
crashes EVERYDAY--- ONE
DEATH EVERY 13 MINUTES.
And this is ONLY in the
UNITED STATES.
WORLDWIDE it is estimated
that 1.2 MILLION are KILLED
and 50 MILLION more are
INJURED in car accidents
every year.
http://en.wikipedia.org/wiki/Traffic_collision
The Ultimate Solution
AIRBAGS
are soft pillows to land against in a
car collision. It is an automobile
safety restraint, much like
seatbelts. It is gas inflated, and
placed at the steering wheel,
dashboard, roof, or seat of a car
that use a sensor to trigger the bag
to inflate and protect the
passenger from the accident.
Statistics show that airbags
reduce the risk of dying by
30% in a frontal crash.
Airbags WORLDWIDE
Airbags are used all
over the world.
In the U.S. Federal
Motor Vehicle Safety
Standards are strict
compared to other
countries.
Popular automobile
makers worldwide, such
as Mercedes Benz,
Porsche, Toyota and
Honda all have airbags
installed in their cars.
How Do Airbags Inflate?
First of all…
The bag is made of nylon fabric and
is folded into the steering wheel,
seat, or door.
The sensor is what makes the bag
inflate. There is a certain amount of
collision force where the bag
inflates. (running into a brick wall
at 16 to 24 km per hour)
A mechanical switch is flips when
there is a mass shift.
accelerometer built into a micro
chip tells the sensor that ta crash
had occurred.
How Do Airbags Inflate?
The airbags inflation system reacts sodium azide (NaN3) with
potassium nitrate (KNO3) to produce nitrogen gas. The nitrogen
gas inflate the airbag.
How Do Airbags Inflate?
The inflation process of an
airbag is similar to how
rocket engines work.
The Solid propellant
inflator burns quickly to
create lots of gas to inflate
the bag.
Then the bag bursts 322 km
per hour--- after a few
seconds the bag will
deflate. (There are tiny
holes in the bag)
Physics Behind Airbags
INERTIA (Newton’s first
law of motion) states that
an object will not change its
motion unless acted on by
an unbalanced force.
According to the law of
INERTIA, a car will keep
moving at the same speed
and direction unless and
outside force acts on it.
Car Driving at Constant Speed
Physics Behind Airbags
When a car collision occurs, the car’s speed changes
instantly--- however the passenger(s) keeps moving according the
law of inertia.
Momentum is the quantity of
motion of a moving body.
(Product of mass and velocity
of an object)
During a car crash, the car’s
momentum has instantly
changed while the passengers
has not.
Physics Behind Airbags
The force needed to stop the momentum of loose objects
in the car--- passengers is very great.
Stopping an objects motion, or changing its momentum
requires a force over a period of time.
And… Airbags provides IMPLUSE (Force x Time)--- a force
acting on an object over time.
An airbag wants to slow the passenger’s speed down, or
change the momentum of the passenger without injuring
him/her.
Physics Behind Airbags
Often times the passenger crashes into the dashboard or windowthis acts as a force to stop the passenger, but it injures them at the
same time.
Car crashes are very quick, the airbag has less than a second to
work with most of the time.
The more time the force or airbag has time to act on the passenger,
there is less damage on the passenger.
This is the result of a
passenger hitting the
dashboard. As you can see his
motion has stopped, however
he was injured because his
momentum was changed or his
speed was slowed down by a
force from a hard surface.
Limitations
Most vehicles today only have frontal airbags which do not
prevent injuries from side, roll over, or rear end crashes.
Most newer models have side and passenger air bags.
Limitations
Airbags do save lives, however it does not prevent injuries
completely. Often times, it is the airbags that are causing these
injuries:
Scrapes
Abrasions
Burns
Fractures
Heart + Chest Lacerations
Eye + Skin Irritation
(because of chemical powder)
Dangers of Airbags
Children & Pregnant Women
Airbags could be dangerous for
children under the age of 13. The force
of the airbag is too strong (explosion of
200 mph), and could cause injury.
Young children should be seated in a
safety seat in the back seat.
Pregnant women should sit as far away
from the steering wheel as possible. A
deployed airbag and its force could
cause loss of an unborn child.
Dangers of Airbags
Distance From Airbag
The passenger could
get injured if he/she
sits too close to the
airbag. When it
deploys, it could
cause severe injury.
If a driver is 2-3
inches away from
the airbag is is risky.
All drivers should
stay at least 10
inches away from
the steering wheel.
Dangers of Airbags
Loss of Hearing
When an airbag inflates during a crash there is a risk
of temporary or permanent hearing loss. (especially
when it is a low speed crash)
The average sound for deployment of airbags are
around 170 decibels. (louder than a jet engine!)
It can cause ear canal bleeding and and permanent
tinnitus (constant buzzing, roaring). This causes
unsteadiness and dizziness and affects hearing,
which makes it a serious condition.
In a smaller car, it is more dangerous, because the
sound is louder and trapped in a smaller space.
Dangers of Airbags
AIRBAGS CAN KILL?!
Between 1990 to 2002, 238 people have been killed by airbags.
Airbags release a tremendous amount of FORCE- an explosion of
200 mph of gas.
When airbags are activated in low speed crashes (low speed
crashes are not much of a threat) and the passenger is sitting 1o
inches or closer to it, the passenger is in great danger in getting
injured or even killed.
Airbags can be a threat especially to children and small women.
Of course, if the passenger wears a seatbelt, his/her body would
not be too close to the airbag in the first place.
Airbags are getting safer
Government statistics prove that airbags are getting safer. In
2008, in the U.S., two children were killed from airbags.
In 1997, there were 53 airbag related deaths. Out of the 53
dead, 31 were children.
Therefore, there is an improvement over the years.
- More people are wearing seatbelts
- More children are placed in the backseat
- Better airbag technology (side airbags, passenger seat
airbags)
Statistics prove newer models of cars and trucks have better
airbag records. (One death caused by 2008 models)
Airbags and Seatbelts
AIRBAGS WERE NOT INVENTED
TO REPLACE SEATBELTS
Airbags are much more effective
if the passengers put their
seatbelt on.
First of all, seatbelts protect the
passenger from roll over or side
impact collision--- where an airbag
can only protect the passengers
from frontal crashes. (considering
that most cars this day only have
front airbags)
Moral + Airbags
Passengers must have morality to wear
a seatbelt--- which increases the
effectiveness of an airbag.
Airbags are effective when used with
seatbelts.
In addition, if the passenger wears a
seatbelt, there would be less or no
injuries or deaths caused by airbags.
- Of the 81 children killed by passenger
seat airbags, 64 were not wearing
seatbelts. (in the U.S.)
Moral + Airbags
HOWEVER…
If there is a fire as a result of
the car crash, seatbelts could
be an obstacle for getting out
of the vehicle.
Also many who were wearing a
seatbelt during a car crash were
bruised badly because of the
tremendous force acting on
him/her.
Political + Airbags
Laws
The government sets the law for the
requirement for airbags.
Negative INFLUENCE
- For ex. The U.S. requires all vehicles to
There are negative
have frontal airbags.
effects to airbags as I
Positive INFLUENCE
explained earlier.
Without these laws, it is not necessary for
Because installing
automobile makers to input airbags in their
airbags is a
vehicles.
requirement, it could be
And… airbags are designed to save lives!
dangerous and cause
injuries or deaths. (For
Also: Seatbelt laws, child seat laws
ex. It is dangerous for
- Increases effectiveness of airbags
shorter women)
- Less dangerous
Political + Airbags
There are frequent
government testing on
airbags or crash testing
programs. (In the U.S.)
INFLUENCE
- Tests different types of
cars and airbags and
evaluate + rate safer cars.
- New technologies could
be developed (further
advanced airbags)
National
Highway
Traffic
Safety
Administration
Crash testing using dummies
are often used by the
government.
Airbags + Environment
SODIUM AZIDE which is used for the inflation
for airbags is very dangerous and hazardous
to the environment.
The amount of sodium azide that could
potentially be released is over 5 million kg.
It is so toxic that small amounts can kills
bacteria, fungi, animals, and even humans.
Ingesting a few grams causes death in 40
minutes for humans.
Studies show that it can kill the seeds of plants
and change soil chemistry.
Sodium Azide
It looks similar to
table salt.
Airbags + Environment
Sodium azide and danger to
the environment does not
affect the effectiveness of
the airbag.
However the main goal of
the airbag is to save lives,
and this substance can kill
humans easily.
If sodium azide is
mistakenly ingested or
leaks, it will defeat the
purpose of airbags.
Sodium azide was used to poison coffee.
Are airbags successful?
YES and NO
Airbags has saved and will
continue to save countless
lives.
However there are dangers to
airbags--- it can cause injuries
and death.
Although the rate of deaths
and injuries caused by airbags
decreasing because of laws and
new technologies.
Future of airbags
The science of airbags are still developing rapidly.
Examples:
Seatback airbags, Door mounted airbag, Curtain airbag, Head
airbag