- The sticky notes have been removed from the meters this week. That, combined with the fact that this experiment now follows February break means that they have completely forgotten how to use an ammeter and voltmeter
- There are 8 wires today (6 long wires, 2 short), which means it's easier for them to connect something incorrectly and create a short (especially with the bulbs). Make sure they don't take additional wires from another setup
- Make sure the current-limiter knob hasn't been turned all the way down to 0. The white line should be set to the 12 o'clock position
- No, they still can't follow directions, and they frequently will miss the point (e.g. they won't set the voltage in the circuit according to the voltmeter, etc.) You need to watch them carefully while they're assembling their circuits and collecting data
- The current and voltage rules usually work very well; any discrepancy is typically very small, and can be attributed to measurement uncertainty and loose connections. Students should be measuring current to 0.1 mA
- Bulbs in parallel: Some will have difficulty connecting the bulbs in parallel. Have them connect just one bulb to the power supply. The should next place the second bulb physically parallel to the first, and make the connections to the first bulb
- When you hear them say "Why aren't these working?", the problem is either:
- they have a bulb that is not screwed tightly into its holder, or
- they've shorted out both bulbs (most likely)
- Fortunately, the current limiter setting on the power supply keeps them from blowing themselves to smithereens
- Series short circuit: They should ask you to check their circuit (if they're reading the damn directions – see above). Have them turn on the power supply (set to 7 volts), then have them close the switch. Ask them to tell you what happened (the shorted bulb goes out, the other bulb gets brighter) and ask them to explain why each happened. Have them think in terms of the voltage across the bulb
- Show & Tell: Jeff will bring in the wire he shorted the last time he was allowed to teach College Physics
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