Final answer:
Students can demonstrate one year using a model with foam balls representing the Earth and the Sun by changing the distance between the foam balls.
Step-by-step explanation:
The correct answer is c) By changing the distance between the foam balls.
When using a model with foam balls representing the Earth and the Sun, students can demonstrate one year by changing the distance between the foam balls. This is because the time it takes for the Earth to complete one orbit around the Sun, which is approximately one year, is influenced by the distance between them. When the distance is increased, the orbital period becomes longer, and when the distance is decreased, the orbital period becomes shorter.
For example, if you move the Earth ball farther away from the Sun ball, it would take more time for the Earth ball to complete one full orbit around the Sun ball, which would represent a longer period of one year. Conversely, if you move the Earth ball closer to the Sun ball, it would take less time for the Earth ball to complete one full orbit around the Sun ball, representing a shorter period of one year.