Adding to the loop

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2. CLICK the picture (and video)
3. TRY this:

Q1: Why do you think that, when people use lots of light, they use mains and not batteries?

[Answer]

When you connect up electrical objects in a single loop, the same amount of electricity flows through everything.

Suppose you had lots of bulbs in a line, such as on a Christmas tree. They would all glow with the same brightness. The electricity is not all used up by the first bulb, leaving nothing for the next.

But to keep the bulbs bright, the more bulbs you have, the more batteries you must add.