Understandings also don't have to be phrased in a way that will be clear to students. In fact, if an understanding is too clear, it might not be worth focusing a unit on.
The prompt for writing EUs is "Students should understand that" rather than "how" or a fact (even an important one). So here are some initial thoughts on understandings for physics, some of which may not be suitable for a first course taken in 10th grade (15-16yrs old).
Students should understand that:
- we can describe motion with words, pictures, graphs, and equations.
- if we know the initial conditions and the acceleration as a function of time for a classical (macroscopic) system, we can predict its future.
- forces are interactions between objects or between an object and a field.
- many physical quantities have direction as well as magnitude.
- the "natural state" of motion is constant velocity, not constant position.
- velocity is the rate of change of position, while acceleration is the rate of change of velocity.
- gravitational forces, static electrical forces, and light intensity all decrease with the square of the distance from the 'source'.
- momentum gives us a way to describe collisions even when we don't know the forces or the forces change too quickly to be useful.
- objects have energy based on their motion and position, which gives us another way to describe them.
- light is both a particle and a wave: the observed behavior depends on the test done.
- moving electrical charges cause both electrical and magnetic fields.
- energy can be transferred between objects and transformed between types, but some is always lost as heat (disorderly, atomic-scale kinetic energy).
- different substances respond at different rates to changes in thermal energy.
What are your thoughts?