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Ohm's Law Explorer

Run the Ohm's Law Explorer MicroSim Fullscreen

You can include this MicroSim on your website using the following iframe:

<iframe src="https://dmccreary.github.io/robot-arm/sims/ohms-law-explorer/main.html"
        height="562px" width="100%" scrolling="no"></iframe>

Description

Change the supply voltage and the load resistance in a simple loop and watch animated current dots speed up and slow down with the ammeter reading. Then solve five challenges that set a target current or power. Used in Chapter 3.

The circuit is the schematic from Chapter 3, drawn by circuit-lib.js, a small library of schematic symbols and animated current dots that is copied into each of the Chapter 3 circuit MicroSims.

Lesson Plan

Grade level: Middle school and up (age 12+). Time: 10 to 15 minutes.

  1. Predict first. Before you move a slider, say what will happen to the ammeter and to the dots.
  2. Explore. Double V, then double R. Notice that the dot speed follows the ammeter, and that the power changes faster than the current.
  3. Challenges. Five targets: set the free slider, then press Check. A free slider and a locked slider are shown for each target.
  4. Think about it. A real motor is not a fixed resistor. Chapter 5 shows why its current changes with load.

The picture is a schematic, drawn with the shared circuit-lib.js helpers. Orange dots show conventional current: they leave the + terminal of the supply, and their speed is proportional to the current.

Specification

The learning objective, evidence of mastery and content for this MicroSim are specified in Chapter 3: Electricity, Power, and Safety Basics.