Fossils provide evidence about the plants and animals that lived long ago and the nature of the environment at that time. The sun, moon, stars, clouds, birds, and airplanes all have properties, locations, and movements that can be observed and described. The sun provides the light and heat necessary to maintain the temperature of the earth. The surface of the earth changes. Some changes are due to slow processes, such as erosion and weathering, and some changes are due to rapid processes, such as landslides, volcanic eruptions, and earthquakes.
Weather changes from day to day and over the seasons.
Weather can be described by measurable quantities, such as temperature, wind direction and speed, and precipitation. Objects in the sky have patterns of movement. The sun, for example, appears to move across the sky in the same way every day, but its path changes slowly over the seasons. The moon moves across the sky on a daily basis much like the sun. The observable shape of the moon changes from day to day in a cycle that lasts about a month.