Illuminations: Volt Meter

# Volt Meter

This applet allows you to learn about positive and negative numbers, by exploring the voltage of batteries.

### Instructions

 Drag the batteries from below the voltmeter to create a circuit. The voltage of the batteries that are placed will be displayed on the voltmeter, and equations corresponding to each representation will appear in the table to the right. Batteries can be removed from the voltmeter by dragging to other locations on the screen. Checking the "Show Equation on Voltmeter" box will cause the equations to display on the voltmeter. The Reset Voltmeter and Reset Table buttons will remove all objects from the voltmeter or table, respectively.

### Exploration

 One at a time, place batteries on the voltmeter. What is the voltage of each battery? How is the voltage different if the terminal of the battery faces to the left instead of to the right? Place two batteries with the same value, but pointing in opposite directions, on the voltmeter. What is the result? Will this happen in all cases? Choose three batteries at random. Before placing them on the voltmeter, predict what the sum (that is, the total voltage) will be. Then, use the voltmeter to check your predictions.

### Lessons

 More and Better Mathematics for All Students
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