Visible flames are hot gases emitting light, which naturally rises because it is hotter (and therefore less dense) than the air around it. These hot gases are byproducts of the chemical reaction of combustion, or burning.Know More
The combustion process requires three things: fuel, heat, and oxygen. Often in everyday situations the fuel is wood. When wood is heated to its "ignition temperature" (300 degrees Fahrenheit) some of the cellulose, the primary material that composes the wood, begins to break down. The decomposed material from the wood consists of ash, non-combustible material left over, and char, pure carbon. The fire also releases hot gases which rise as smoke.
When the gases (or smoke) are hot enough (around 500 degree Fahrenheit) their compound molecules break apart and react with oxygen to form water vapor and carbon dioxide, as well as carbon monoxide, particles of pure carbon and nitrogen. This recombination is the chemical process known as combustion. All of these chemical reactions produce a large amount of heat, and as the rising particles heat up, they emit light.Learn More
Air is a good insulator because its molecules are very far apart. This makes it difficult to transfer heat, according to Dr. Ken Mellendorf, a physics professor at Illinois Central College.Full Answer >
When a volume of air is heated, it expands, if the volume is not contained in a rigid container. If the air is in a rigid container, the internal pressure increases against the walls of the container.Full Answer >
Hot-air balloons work based on the principle that hot air is lighter than cool air. By using a propane burner that heats the air inside the balloon, the air inside the envelope, or the top part of the balloon, becomes lighter than the surrounding air, causing the balloon to rise.Full Answer >
When all the frequencies of visible light are combined, the resulting light is perceived as white by the human eye. White light contains all frequencies of light at roughly equal intensities. The process of splitting white light into its component colors is called dispersion.Full Answer >