AIR

AIRBAGS

By Alisa Kawashita

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.

ProblemDeaths and Injuries Caused by CarCrashes

http://en.wikipedia.org/wiki/Traffic_collision

AIRBAGSare 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.

The Ultimate Solution

Statistics show that airbags reduce the risk of dying by 30% in a frontal crash.

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.

Airbags WORLDWIDE

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.


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)


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.

Physics Behind Airbags

Car Driving at Constant Speed

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.

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.


Often times the passenger crashes into the dashboard or window- this 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.

Most vehicles today only have frontal airbags which do not prevent injuries from side, roll over, or rear end crashes.

Limitations

Most newer models have side and passenger air bags.

Airbags do save lives, however it does not prevent injuries completely. Often times, it is the airbags that are causing these injuries: ScrapesAbrasionsBurnsFracturesHeart + Chest LacerationsEye + Skin Irritation (because of chemical powder)

Limitations

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 AirbagsChildren & Pregnant Women

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 AirbagsDistance From Airbag

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 AirbagsLoss of Hearing

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.

Dangers of Airbags

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 are getting safer

AIRBAGS WERE NOT INVENTED TO REPLACE SEATBELTSAirbags 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)

Airbags and Seatbelts

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.

Moral + Airbags

The government sets the law for the requirement for airbags. - For ex. The U.S. requires all

vehicles to have frontal airbags.Positive INFLUENCE

Without these laws, it is not necessary for automobile makers to input airbags in their vehicles. And… airbags are designed to save lives! Also: Seatbelt laws, child seat laws- Increases effectiveness of airbags- Less dangerous

Political + AirbagsLaws

Negative INFLUENCE

There are negative effects to airbags as I explained earlier. Because installing

airbags is a requirement, it

could be dangerous and cause injuries

or deaths. (For ex. It is dangerous for shorter women)

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)

Political + Airbags

Crash testing using dummies are often used by the government.

National Highway Traffic Safety Administration

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.

Airbags + Environment

Sodium AzideIt looks similar to table salt.

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.

Airbags + Environment

Sodium azide was used to poison coffee.

YES and NOAirbags 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.

Are airbags successful?

The science of airbags are still developing rapidly. Examples:

Seatback airbags, Door mounted airbag, Curtain airbag, Head airbag

Future of airbags

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