In *Proportionality: The X-Plane Generation*, students are introduced to the scale model as an engineering tool by using NASA’s experimental aircraft, the X-33, as an example. Students may be familiar with scale models from toys, building kits, or from playing with dolls and dollhouses.

This episode of NASA CONNECT focuses on the math concepts of computation, estimation, ratios, and measurement and illustrates a systematic scientific investigation. Students will meet NASA researchers and other professionals who will (a) describe the relationship between force, energy, and motion; (b) discuss how NASA’s experimental X-plane is being tested to make space travel more reliable; (c) show students how proportionality and ratios are used to make scale models of spacecraft like the X-33; and (d) describe how scale models are more manageable than full-scale models when it comes to testing and retesting their designs.