Oh, I feel foolish.
To be frank, my experience and knowledge is based only on IQ tests on websites. Once I came upon a test that asked me the meaning of some words... Strange thing. If real IQ tests never use questions that require knowledge and education then you are completely right. Thank you for pointing out my mistake.
CrunchyMittens, what are you talking about? IQ measures pattern recognition and problem solving, also known as fluid intelligence. It also measures how quickly you do it. IQ tests never measure crystal intelligence exactly because, as you point out, they are too affected by what you know. IQ tests still stand as the most valid of the intelligence test, though of course it has its share of critics. Any test that measures something as amorphus as intelligence will. However, I think you are thinking of other intelligence tests, not the IQ test, with your critique.