This creates clouds and, if there is enough moisture, precipitation.
Heat gets into the room in two ways: convection and infrared radiation. The "fins" of a radiator heat the air molecules around it, causing them to expand. As the hot air expands, it rises, creating a vacuum behind it.
Cooked air rises creating a high pressure system below
The density is reduced to 50% (half) of its original value.
The air pressure rises in your chest
Fluids rise and sink in a convection current due to differences in temperature and density. When a fluid is heated, it becomes less dense and rises, creating an upward flow. As it cools, it becomes more dense and sinks, creating a downward flow. This continuous cycle of heating and cooling drives the convection current.
precipitation (rain)
RAIN
High and Low Pressure
Water that is heated expands and rises to the surface of the tray. Similarly, the magma expands and rises to the surface of the tray. Similarly, the magma nearer the core expands and rises to top of the mantle.
Warm air rises at the equator and cold air sinks at the poles. Warm air expands and cool air contracts and compresses.
At the equator, intense sunlight warms the air and causes evaporation of water from the ocean. As the air heats up, it expands and rises.
It expands and cools
Cake expands or "rises" because of air that has been incorporated into the batter that expands when it is heated. Many cakes also have baking soda or baking powder that causes expansion by acid/alkaline reaction.
rising air expands then cools and condenses
The object expands
The object expands
Heat. As the air expands (as it's heated), it rises and causes air to flow upward.