1. Materials come in different forms (states) including solids, liquids, and gases. As a basis for understanding this concept, students know

• solids, liquids, and gases have different properties
  
• the properties of substances can change when the substances are mixed, cooled, or heated.

2. Plants and animals meet their needs in different ways. As a basis for understanding this concept, students know

• different plants and animals inhabit different kinds of environments and have external features that help them thrive in different kinds of places
  
• plants and animals both need water; animals need food, and plants need light
  
• animals eat plants or other animals for food and may also use plants or even other animals for shelter and nesting
  
• how to infer what animals eat from the shapes of their teeth (e.g., sharp teeth: eats meat; flat teeth: eats plants)
  
• roots are associated with the intake of water and soil nutrients, green leaves with making food from sunlight.

3. Weather can be observed, measured and described. As a basis for understanding this concept, students know

• how to use simple tools (e.g., thermometer, wind vane) to measure weather conditions and record changes from day to day and over the seasons
  
• the weather changes from day to day, but trends in temperature or of rain (or snow) tend to be predictable during a season
  
• the sun warms the land, air, and water.

4. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept, and to address the content the other three strands, students should develop their own questions and perform investigations. Students will

• draw pictures that portray some features of the thing being described
  
• record observations and data with pictures, numbers, and/or written statements
  
• record observations on a bar graph
  
• describe the relative position of objects using two references (e.g., above and next to, below and left of)
  
• make new observations when discrepancies exist between two descriptions of the same object or phenomena.