This particular lesson can be used across all the grades. I've used it with 3, 4th and 5th and I know other colleagues that have used it in middle school and high school. You can increase the depth. For instance, older students can do more complex calculations of velocity and create tables and graphs to present their information. All grades can graph (it is a good idea to start graphing and presenting data in an organized manner from early on).
I also allow the students to choose what variable they would like to change in their experiment. They do group investigations and present their finding on a mini- science board. The class then discusses t heir findings and compare it to what their group has done.
I really enjoy the Force and Motion unit. Due to our old textbooks, I've had to find other resources on and off-line to help with this particular unit. This class has presented many additional ideas I'd like to try.