As a rule, people do not notice the air surrounding them. In usual conditions it is absolutely transparent, has no taste and a smell, it is possible to feel its movement only. However in the aggregate states differing from gas on limits of the section of environments and also in certain conditions air can be seen.
It is required to you
- - tube;
- - container with water;
- - powerful light source;
- - powerful source of heat.
Instruction
1. Carry out simple experience according to air. Take the container with water, lower in it one end of a small plastic tube and blow from other its party. You will see the vials of air passing through water. In spite of the fact that air and water are absolutely transparent, bubbles are visible. It occurs thanks to the different optical density of these substances that causes partial reflection and light refraction on limits of the section of environments.
2. Make the experiment allowing to observe shadows of convection air flows. Take very bright desk lamp. Direct it to the light screen. It can be a leaf of a Whatman paper or just a wall with light wall-paper. Between a lamp and the screen place a powerful source of heat. It is possible to use the electric heater having an open spiral. On the screen chaotically moving shadows will be visible. This effect is caused by various optical density of air at different temperatures. Thereof there is an uneven refraction of light beams on borders of contact of warm and cold air masses.
3. It is possible to see also liquid air. At and temperature about -190 °C it turns into the corresponding aggregate state. Liquefaction of air is made on special installations by method of increase in pressure with continuous cooling.
4. It is possible to observe air in a condition of strong ionization. It will shine. The similar effect arises, for example, during a thunderstorm in the form of fires of the Saint Elma representing crown categories near sharp conductors, such as metal spires on masts of the ships or high towers. For emergence of crown categories rather high tension of electric field is necessary. But today similar categories can be received in vitro.
5. Air can be seen if to transfer it to a condition of plasma by very strong heating. It will begin to shine. The similar effect is observed at atmospheric nuclear explosion. Having applied decomposition of radiation of heated air by means of an optical system on the basis of prisms, it is possible to see "luminescence" of separate components it gases.