The content standards for K-4 from the National Science Education Standards are divided into three parts: 

Properties of Earth Materials

• Earth materials are solid rocks and soils, water, and the gases of the atmosphere. The varied materials have different physical and chemical properties, which make them useful in different ways, for example, as building materials, as sources of fuel, or for growing the plants we use as food. Earth materials provide many of the resources that humans use.
• Soils have properties of color and texture, capacity to retain water, and ability to support the growth of many kinds of plants, including those in our food supply.
• Fossils provide evidence about the plants and animals that lived long ago and the nature of the environment at that time.

Objects in the Sky

• 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.

Changes in the Earth and Sky

• 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.