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Speed and Collisions
Contributed by: Council of Chief State School Officers (CCSSO)

The point of this event is to show students that speed is an important variable regarding force of an impact.

Main Points:

  1. For a car rolling down a ramp, speed is determined by the slope of the ramp and the distance the car travels on the ramp.

  2. Speed is directly proportional to the severity of an impact. The higher the speed, the harder the impact.

  3. As long as only one variable is changed at a time, a relationship can be derived from an experiment which is accurate no matter the size of the materials used in the experiment.

Criterion 1:   Student correctly fills out table 1. The table should be complete with both trials and accurate speed calculations. The calculations don't need to be exact, look for glaring errors.
Criterion 2:   Student performs another study in which they change the experiment by either changing the slope of the ramp, changing the distance the car travels or both. The student must record the new speed of the car and the distance the block moved. The data doesn't need to be accurate or make sense however and they do not need to have two trials. The data can be either below table 1 or in question 1 and they must mention what they did to change the experiment.

Example:  We moved the car back another 7 cm and tested it again.

2 sec.
Criterion 3:   Student makes the correct conclusion that the higher the speed of a car the harder the impact it will have or the farther the block will move. The student may refer to the specific situation with the toy car and the block or make a general statement of impacts.


  1. The faster we made our car move, the farther the block moved.
  2. Faster cars have harder impacts.
Criterion 4:   The student gives at least one reason why their experiment was accurate or inaccurate. Reasons might include:
  1. We only changed the speed.
  2. In real cars, slower cars don't have as bad an accident as fast cars.
  3. Student mentions a problem with the experiment such as inaccurate timer, defective car, ramp, or track.



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