science vs. technology

It is so hard to get my students past their assumption that science and technology are the same thing. I tried today to talk about pure science, but only a few could imagine that some scientists just want to know how the universe works, aren't working towards some practical goal. They also think of science as any knowledge of the natural world, so someone building a waterwheel must be using physics because they are using their knowledge of gravity. I told them I am interested in a change that took place when technology began to be based on formal science. A student came up to me after class and said he wasn't convinced that that was a major change; I wasn't giving colonial Americans enough credit for using their knowledge of the world to develop new technology.