AC vs DC Current Path Model

Tesla’s work helped AC power systems become practical on a large scale. Jennifer and Daniel learn that direct current, DC, flows in one direction, while alternating current, AC, repeatedly reverses direction. Children use paper arrows and a moving marker to compare these patterns without electrical equipment. Their model helps them describe how current changes and why a wave drawing represents changes over time rather than the shape of a wire.

Materials Paper, markers, a ruler, one paper marker, and two cards labeled DC and AC.

Experiment or Activity 

1. Draw one straight track. Mark its center.

2. For DC, move the marker along the track in one direction. Draw arrows showing that direction.

3. For AC, move the marker back and forth around the center. Draw arrows for each direction.

4. On separate paper, sketch a wave labeled Current and Time. Explain that it shows current changing with time, not a wavy wire.

Safety note This is a paper model only. Do not connect electrical equipment. The moving marker represents the direction of current, not the exact motion of an individual electron.

What children learn DC and AC describe current direction. Transformers can change AC voltage, which helped make long-distance power transmission practical. Both AC and DC are useful today.

Think about it What does the wave drawing represent?