Performance Expectations: 5-PS1-1: Develop a model to describe that matter is made of particles too small to be seen.

Disciplinary Core Idea: PS1.A: Matter of any type can be subdivided into particles that are too small to see, but even then the matter still exists and can be detected by other means. A model showing that gases are made from matter particles that are too small to see and are moving freely around in space can explain many observations, including the inflation and shape of a balloon and the effects of air on larger particles or objects. (5-PS1-1)

Cross cutting concepts: Scale, Proportion, and Quantity ▪ Natural objects exist from the very small to the immensely large.