Friday, April 11, 2008

There are three kinds of airships that have been manufactured: blimps, dirigibles, and hot air balloons.




What is the mechanism of flight for each one? That is, how does each fly?

A blimp uses gas that is lighter than air to generate lift. Today they use helium, becuase it is not flammable. As the blimp rises, outside air pressure decreases and the helium in the envelope expands.

A hot air balloon uses hot air to lift off and stay afloat. Hot air is lighter than cool air because it has less mass per unit volume.

Dirigibles produce lift by filling its main cavity with another gas that is lighter than air.

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

http://travel.howstuffworks.com/hot-air-balloon.htm

http://travel.howstuffworks.com/blimp2.htm

There are three kinds of airships that have been manufactured: blimps, dirgibles, and hot air balloons.

How are these airships similar? How are they different?

All of theses airships are similar in the fact that they use gas to create lift.
How they use the gases to stay buoyant is a little different.

Dirigibles and blimps fill the main envelope with gas that is lighter than air. Dirigibles have a fixed frame, so they can only hold a set amount of helium in it's envelope. Hot air balloons make the air in the ships bladder hot by keeping a flame lit right under it.

Blimps can actually steer and hover, where as blimps can only go where ever the wind blows them.


http://www.aerospaceweb.org/question/history/q0169.shtml

There are three kinds of airships that have been manufactured: blimps, dirgibles, and hot air balloons.

What are the relative advantages of one over the other?

Hot air balloons cannot control where the go. They just float with the breeze.

Dirigibles and blimps have very similar qualities. They both can control where they go and how fast they move.

There are three kinds of airships that have been manufactured: blimps, dirgibles, and hot air balloons.

What are the limitations of each?

The limitations for hot air balloons are that they cannot be loaded as much on hot days as on cool days.

Blimps and dirigibles are usually extremely large in size and therefore not very maneuverable.


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

There are three kinds of airships that have been manufactured: blimps, dirgibles, and hot air balloons.

Give historical examples of each and be sure to include at least one photo for each one.

One historic example of a dirigible is The Hindenburg.

http://www.failuremag.com/images/hindenburg.jpg







Here is the Coca-Cola Hot Air Balloon.

http://www.otownmedia.com/images/balloons.jpg







The Good Year Blimp

The German zeppelin Hindenburg was filled with hydrogen gas. Not surprisingly, the airship was destroyed in a violent fire.....

The German zeppelin Hindenburg was filled with hydrogen gas. Not surprisingly, the airship was destroyed in a violent fire near Lakehurst, New Jersey on May 6, 1937.

Write the balanced chemical equation for the combustion of hydrogen.


2 H2 + 1 O2 → 2 H2O

The German zeppelin Hindenburg was filled with hydrogen gas. Not surprisingly, the airship was destroyed in a violent fire......

The German zeppelin Hindenburg was filled with hydrogen gas. Not surprisingly, the airship was destroyed in a violent fire near Lakehurst, New Jersey on May 6, 1937.

We know that chemical reactions are often exothermic or endothermic. What do these words mean in terms of chemical reactions? What are observable chemical indicators of each? Is the combustion of hydrogen exothermic or endothermic?



When a chemical reaction is exothermic it means that heat was released in the reaction. A exothermic reation has taken place when heat light or sound has been released. The combustion of hydrogen is exothermic.
http://chemistry.about.com/od/lecturenotesl3/a/endorxns.htm
http://www.openencyclopedia.net/index.php/Exothermic_reaction

When a chemical reaction is endothermic it means that heat was absorbed during the reaction. Usually, when a substance is melted, boiled or evaporated, it indicates that a endothermic reaction has taken place.

http://chemistry.about.com/od/lecturenotesl3/a/endorxns.htm

Modern airships are filled with helium.

Why are modern airships filled with helium?

Modern airships are filled with helium, because helium is not flammable.

http://www.kidcyber.com.au/topics/airshipballoon.htm

Modern airships are filled with helium.

Why wasn't the Hindenburg filled with helium instead of hydrogen?

The Hindengurg was originally planned to use helium, but the majority of the world's helium supply comes from the US, and the US had a military imbargo on it. So the Germans changed the design of the ship to use hydrogen.

http://tripatlas.com/Hindenburg_disaster

Modern airships are filled with helium.

Using a diagram of orbital diagrams or electron configurations or both, explain why helium is safer than hydrogen for use in airships. Use diagrams and words to explain your answer.




Helium

Helium is safer to use in airships because it is a Noble gas and it has a nucleus.














Hydrogen


Hydrogen is more reactive and less stable than Helium.










http://www.apsidium.com/elements/001.htm

Though more potentially dangerous, a given volume of hydrogen gas will lift more weight than an equal volume of helium because hydrogen......

Though more potentially dangerous, a given volume of hydrogen gas will lift more weight than an equal volume of helium because hydrogen is less dense than helium.

Use Avogadro's hypothesis to explain why hydrogen is less dense than helium.


If you have one mole of each, and since hydrogen has less mass per mole than helium, it makes hydrogen less dense than helium.

The Hindenburg was filled with flammable hydrogen but recent research suggests that hydrogen was not the primary matrrial involved in its tragic demis

How did a paint made from powdered aluminum contribute to the disaster?

The paint that was used on the Hindenburg was coated with flecks of aluminum, which is a component of rocket fuel. The paint caught fire from an electric discharge, then ignited the hydrogen.

http://americanhistory.about.com/od/hindenburg/a/hindenburg_3.htm



The Hindenburg was filled with flammable hydrogen but recent research suggests that hydrogen was not the primary matrial involved in its tragic demise

How is powdered aluminum used on the current United States Space Shuttle?

Powered aluminum is used as a component of fuel for the US Space Shuttle.

The Hindenburg was filled with flammable hydrogen but recent research suggests that hydrogen was not the primary matrial involved in its tragic demise

Write the balanced chemical equation for the reaction aluminum underwent in the Hindenburg disaster. Also indicate if this reaction is exothermic or endothermic.

2 Al + 1 O2 → 2 AlO
The reaction was exothermic.

The Hindenburg was filled with flammable hydrogen but recent research suggests that hydrogen was not the primary matrial involved in its tragic demise

Use the octet rule to explain why powdered aluminum can behave as it is thought to have done in the Hindenburg disaster.

Powdered aluminum acted as it did to The Hindenburg because, it does not have a full octet of electrons. Since it does not a full octet, it is very unstable.

The Hindenburg was filled with flammable hydrogen but recent research suggests that hydrogen was not the primary matrial involved in its tragic demise


Do you think an aluminum can would behave in the same manner as powdered aluminum? Explain your answer in detail.

Aluminum would behave the same as powdered aluminum under different conditions. For example, you would have to heat aluminum to about 2300 degrees Celcius for it to burn. For powdered aluminum to ignite, you would only have to have an electrical charge.

http://www.angelfire.com/al/aluminum/aluwebsayfam2.html



The Hindenburg was filled with flammable hydrogen but recent research suggests that hydrogen was not the primary matrial involved in its tragic demise

Describe the experiments carried out by Addison Bain. Then, explain how his results and other evidence led to the conclusion that the skin of the Hindenburg was the major cause of fire that destroyed the airship.


Bain thought that the hydrogen in The Hindenburg was not the main factor in the initiation of the catastrophe. He found out that parts of the skin was still on fire even after it was seperated from the region of densest hydrogen.



Hot air balloons are filled with air instead of helium.


How does the handler "pilot" his airship? That is, how does the pilot get the balloon to go up into the sky? How does the pilot get the balloon to descend to the ground? Explain how the pilot travels north, south, east or west. What kind of control do they have over this?


A hot air balloon pilot increases the flame by turning up the flow of gas, which increases vertical speed. Hot air balloons also have a cord to open the parachute valve at the top of the envelope. When the pilot pulls the attached cord, some hot air can escape from the envelope, decreasing the inner air temperature. This causes the balloon to slow its ascent. If the pilot keeps the valve open long enough, the balloon will sink. To move the aircraft north, south, east, or west the pilot either ascends or descends in altitude to catch different wind currents.


Hot air balloons are filled with air instead of helium.

Use the ideal gas law to explain why a hot air balloon rises.

When you heat the air in the envelope of the hot air balloon, you increase the absolute temperature, which in turn increases the pressure of the balloon, and elevates the hot air balloon.

http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/idegas.html

French chemist, Joseph Gay-Lussac is most famous for his description of the gas law, Gay-Lussac's Law.

What is the formula for Gay-Lussac's gas law?



http://dbhs.wvusd.k12.ca.us/webdocs/GasLaw/Gas-Gay-Lussac.html

French chemist, Joseph Gay-Lussac is most famous for his description of the gas law, Gay-Lussac's Law.


Explain Gay-Lussac's law using words to describe the relationship between the variables. What are the assumed constants in Gay-Lussac's law?

The pressure of a fixed amount of gas at fixed volume is directly proportional to its temperature in kelvins.

P is the pressure of the gas.
T is the temperature of the gas (measured in kelvins).
k is a constant.

http://en.wikipedia.org/wiki/Gay-Lussac

French chemist, Joseph Gay-Lussac is most famous for his description of the gas law, Gay-Lussac's Law.

How did Gay-Lussac use balloons to study chemistry in the early 1800s?

He increased the kinetic energy of the gas in the balloon as it's particles collide more frequently, thus increasing pressure of the balloon.


http://en.wikipedia.org/wiki/Gay-Lussac's_law

French chemist, Joseph Gay-Lussac is most famous for his description of the gas law, Gay-Lussac's Law.

What did he learn from investigations he carried out using a hot air balloon?

When you increse the kinetic energy of a gas, you increase the pressure of the gas.

http://en.wikipedia.org/wiki/Gay-Lussac's_law

It makes sense that a balloon filled with a lightweight gas such as helium would float when surrounded by heavier air.....

But why does filling a huge balloon with hot air also make it float? This resource from the NOVA website offers a series of interactive activities that describes and illustrates the chemistry (mass, volume, density) of what happens inside hot air balloons.

Go through this
NOVA site and then summarize the key points learned.

Equal volumes of materials can have different masses. Density is the relationship between material's mass and its volume. Helium has less density than air. When heated, hot air balloon's total mass of air will decrease yet, it's volume will stay constant.

An airplane typically cruises at an altitude of 30,000 - 40,000 feet.

Hypothesize what problems might be encountered in a suddenly depressurized airplane cabin at 30,000 feet. Be sure to use what you have learned about the gas laws in answering this question.

When you depressurize a cabin suddenly at 30,000 feet, the passengers would probably pass out and wake up with tremendous headaches.

http://www.rense.com/general67/cypriotplanecrashes.htm

An airplane typically cruises at an altitude of 30,000 - 40,000 feet.

There are many myths regarding sudden depressurization. What are some of the myths?

If you shoot a gun off in an airplane cabin, the cabin will depressurize instantly.
If a plane is suddenly depressurized, every passenger's head would explode.

http://www.freerepublic.com/focus/f-news/528265/posts

An airplane typically cruises at an altitude of 30,000 - 40,000 feet.

What would actually happen if a window or emergency door came off of a plane cruising at 30,000 feet? Why? Be sure to use what you have learned about the gas laws in answering.

If an emergency door came off a plane at 30,000 feet, anyone standing near the door will sucked out. Then the cabin will cool and become very foggy due to the rapidly expanded cabin air.

http://www.madsci.org/posts/archives/jan2001/980973572.Ph.r.html