Directions 1. Have students explore the Powers of Ten websites This activity has introductory materials that make it optional at the high school level. Show students websites that illustrate the Powers of Ten (see links in the Extending the Learning section below). 2. Have students sort cards according to scale. Divide students into groups of four. Pass out one copy of the Powers of Ten 11 x 17 Poster to each group, or a smaller version as a handout. Give one copy of 2.2 Powers of Ten Cards to each group. Each individual student should get about six cards. Ask students to place their cards on the correct scale on the poster—large scale, macroscopic scale, microscopic scale, or atomic-molecular scale. Tell students they can use the interactive websites and discuss among themselves to determine the scale each card should go on. Have students work in groups for about 10-20 minutes, placing each card into one of the four categories. Ask students to think of examples of similar systems or objects (plant, people, water, fuel, fire, pollen) at different scales (large, macro, micro, atomic-molecular). 3.Have students discuss the sorting process. Ask each group of students to share with their classmates where they placed one or two cards. Have students in each group reveal any questions they had about cards they were not sure of. Discuss their questions with the class as a whole. If they don’t notice on their own, point out that the cards are organized into groups: plants, people, water, fuel, fire, and pollen systems. 4. Discuss why scientists think about scales. Tell students that scientists try to understand systems at many different scales. Ask students why they think scientists might use scale as a tool to interpret the world. In the next activity they will be looking at a very important system at different scales—air. Place a copy of the Powers of Ten with Pictures 11 x 17 Poster on the wall in the classroom for future reference. This version has examples of objects and systems at each scale.