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Meteorology
3.3 Temperature and density
Temperature is a measure of the average kinetic energy of the particles in a
substance.
As temperature increases, it means that the particles (molecules, atoms, etc.)
are moving faster. Conversely, when temperature decreases, particles move
slower.
Density is a measure of how much mass is packed into a given volume of a
substance.
Density is dependent on temperature, as the substance expands and becomes
less dense when the temperature rises because the molecules move faster and
occupy more space. Conversely, most substances become denser at lower
temperatures, as the molecules move slower and pack more tightly together.
3.3.1 The seasons
Throughout the year, Earth moves around the sun in an elliptical orbit.
At the same time, Earth rotates around itself once every 24 hours. Earth's axis
is tilted by about 23°.
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