Weather balloons
Weather balloons have been used since World War II. Weather balloons are used alot more then you might think. Every 12 hours a balloon is released at each of 70 sites around the United States. There are more then 700 sites around the world. They are released at the same time in all countries; at 6:00 and 18:00 hourse Greenwich Mean Time. The balloons are used to provide scientists data that is used in the country's eather forcasts. They provide imformation about temperature, pressure, relative humidity and wind velocity. All the data from other countries is sent to a central computer in Maryland.
The balloons are filled with helium or hydrogen. An insterment is attached to the balloon. When the ballon reaches a height of 30 km, the ballon bursts and the measuring insterments are carried via parachute to the ground.
external image WeatherBalloon_big.jpg1. Weather satellites can only do so much. Weather balloons have been here for awhile and are still doing their job. They are sent up in the air to collect the weather pressure and what not. They are still needed to collect certain kinds of data.
2. You wouldn't want to put to much gas into the balloon or things might not work properly. Or if you some how built somthing that would react with the gas you have to know the laws so you dont screw up.




Hyperbaric Oxygen Chambers
These chambers have been used since the 1940's. They were once used to treat divers with decompression sickness. Over many years these HBO chambers have shown to be useful in much more. They can be used to heal bone and muscle injuries. With sports injuries it compresses the air to 3 atm of pressure around the injured player. They are breathing pure oxygen through a mask. The higher air pressure forces more oxygen to dissolve in the bloodstream, speeding up the flow of oxygen. This helps with swelling by reducing it. it helps heal it.
It can also be used to help people who have suffered heart attacks. Patients who had HBO therapy experienced pain for less time. There heart also returns to normal functions faster.