LOOKING FOR A GAS
You want to identify a gas? Maybe you're standing next to your friend and you hear him make a little farting noise. No. We're not talking about that kind of gas. Flatus is not funny. Well maybe it is but it has no place here. Not yet anyway.
Gas is everywhere. There is something called the ATMOSPHERE. That's a big layer of gas that surrounds the Earth and it's all gaseous. Gases are random groups of atoms. There are solids where atoms and molecules are really compact. Liquids have them a little more spread out. But gases are really really spread out and the atoms and molecules are full of ENERGY, bouncing around constantly.
One of the physical characteristics is that a gas can fill a container of any size or shape. Think about a balloon for a minute. No matter what shape you make the balloon, it will be completely filled with the gas. The atoms and molecules are spread equally throughout the entire balloon. Liquids can only fill the bottom of the container while gases fill it entirely.
SO YOU WANT TO BE A GAS
We're betting that you want to be a gas right now. Trust us, it's easier to make gas than to become one. First you need some beans. No, actually you need energy to become a gas. The atoms in a gas have more energy than the atoms in solids and liquids. The easiest way to think of energy is to think of temperature. When you increase the temperature of a system you are pouring energy into that system.
When you want to be a gas you usually start out as a liquid. When you add energy to a liquid, the atoms get all excited. When you boil water, the steam you see is small water droplets being carried by the rising water gas/vapor. You can also find water vapor in fog and clouds. The special temperature when a liquid becomes a gas is called the BOILING POINT. When you cool a gas it liquefies. When a gas becomes a liquid the speed and energy in the molecules drop and ATTRACTION forces allow the molecules to group together.
You might hear the term vapor. Vapor and gas mean the same thing. The word vapor is used to describe gases that are usually found as liquids, like water. You see a compound like CO2 is usually a gas, so it described that way. But water (H20) is usually found as a liquid at room temperature. So when it becomes a gas, scientists use the term vapor.
Sometimes a liquid can be sitting there and its molecules will become a gas. That's called EVAPORATION. You might be wondering how that can happen when the temperature is low. It turns out that all liquids can evaporate at room temperature and pressure. Evaporation is when there are atoms or molecules escaping from the liquid and turning into a VAPOR. You see, not all the molecules in a liquid actually have the same energy. The energy you can measure is really an AVERAGE of all the molecules. There are always a few molecules with a lot of energy and some with barely any energy at all. It is those with a lot of energy that build up enough power to become a gas and leave the liquid. When it leaves it has evaporated.
Enrico Fermi. Italian. Physics Madman. He was one of the first experts on the nucleus of the atom. In 1934 he came up with a theory talking about beta-decay. That's when a nucleus breaks down and one of the results is a beta-particle. It has to do with radioactivity. In 1938 he came to the United States, the foremost expert of neutrons.
Once he came to the U.S. he also worked on the Manhattan Project. That was the team of scientists which developed the first atomic bomb. To top it all off, he won the Nobel Prize for Physics because of his work on radioactivity. You might ask, "What this all has to do with chemistry?" He was one of the leaders on atomic structure research. That's like a whole section of Chem4Kids!