Read the excerpt from The Boy Who Harnessed the Wind by William Kamkwamba.After two more weeks of reading this book, I found the most fascinating chapter – the discussion of magnets. I knew about magnets because they were used to make the speakers in radios. I'd busted off a few and taken them to school as toys, moving little slivers of metal around through a piece of paper. But as I read further, I discovered that some magnets – called electromagnets – are used to generate electricity, specifically in simple motors, like those found in a radio.