A compass for current

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In an electric circuit the current always flows from the negative pole of the voltage source to the positive pole of the voltage source. If you now reverse the polarity of the battery, the current flows in the other direction through the circuit. Around the wire a magnetic field is created again. Due to the fact that the magnetic needle is oriented according to the current, the needle points in the opposite direction now. You can observe this by using the compass within the experiment. In order to compare the results, you may want to take a picture of the compass needle in both cases. Pay special attention to the blue tip of the needle. In which direction is it pointing to?

Roll your mouse over the picture to enlarge the compass.

Der Kompass zeigt nach der Umpolung in die entgegengesetzte Richtung.

Note, that swapping the coloured wires is for illustration purpose only. It is important that the battery has been turned around, so the negative pole which is on the left in the left picture is on the right in the right picture.



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