North Carolina Grade 7 Science

Read motion from a position–time graph

Read an original position–time graph in North Carolina Grade 7 science, explain direction and displacement, and find selected references, lessons, and quizzes.

The current NCDPI science resources page links the 2023 North Carolina Science Standard Course of Study, approved July 2023. Selected references here use the actual North Carolina grade-level codes and clauses. This activity selects a Grade 7 objective in the North Carolina document. It is one part of a science course, not a complete curriculum.

The state document explains that standards provide a framework while public school units and schools write their curriculum. Read the complete grade objectives alongside the school’s course, including investigations, models, evidence, and explanations. The general lesson library below may include review or enrichment beyond this grade’s course. This original activity is a focused starting point, not a complete curriculum crosswalk.

Read motion from a position–time graph

Study the invented graph of an object moving along one line. Positive position is measured from a fixed reference. The object moves from 0 to 6 meters during seconds 0–2, remains at 6 meters during seconds 2–4, then moves to 2 meters by second 6. Explain each part of the graph. Find its net change in position and the distance traveled in this idealized record. Why does the final downward segment not mean that time runs backward?

Explain the evidence or model

The rising segment shows position increasing by 6 meters in 2 seconds. The flat segment shows no change in position during the next 2 seconds, so the object remains at the same position in this model. The falling segment shows a 4-meter movement toward lower position values while time continues increasing. Its final position is 2 meters from the starting reference, so net position change is +2 meters. The path length is 6 meters outward plus 4 back, totaling 10 meters. Position is not cumulative distance traveled: returning toward the reference lowers position without subtracting distance already traveled. Each straight segment assumes constant motion within its represented interval; the record is an idealized model, not a claim about an actual vehicle.

What to check in the explanation

A flat position–time segment means unchanged position, not the same speed as a rising segment. Do not read the vertical value as height above the ground unless that is the defined coordinate. The final negative slope shows direction toward smaller positions, not negative elapsed time. Graphical interpretation is the selected focus; the model supplies no measured force.

Plan the next activity

1. Read the axes and fixed reference first.
2. Describe each interval using changes in position.
3. Separate total distance from net position change.

Draw a record that ends back at zero after moving 6 meters outward and 6 meters back. Explain why net position change is zero while distance is 12 meters. Keep the same reference and labeled axes.