# This gap text shows you how. However, it is up

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Worksheet: From an observation to an explanation of our experiment
How do we get from a first observation in an experiment to a useful explanation?
This gap text shows you how. However, it is up to you to find the right solutions …
Two light bulbs in an electric circuit
bulb. We placed this second light bulb either in front of or behind the first one. Our
observation was: both lamps have ______________ brightness1 (approximately2).
This is not a big surprise for us, because the same ______________ has to go through
both light bulbs.
Besides, the use of a second light bulb – with constant generator rotation speed – had
as a result that both light bulbs were shining _____________ brightly than a single
bulb in the same circuit. At the same time, turning the generator had become
_____________ than before. Both observations lead to only one conclusion: with
two light bulbs and at the same speed of generator rotation, there is ______________
than with one light bulb.
Why is this the case3? We already know: the bigger the ______________________
that the current has to pass, the _______________________ is the current. In this
way, electrical devices4 (with different _________________ inside) control the current flowing through them and through this also their ______________________
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intake. If the use of two bulbs in a series connection in one circuit causes less
_________________________, then the reason for this has to be that two light bulbs
cause twice the _________________as one. There is less ____________________
flowing and therefore also less power, so the two bulbs shine less brightly.
1 describes how bright sth. is (Helligkeit)