I can only speak from my personal experience, nobody motivated me to do
science, I loved it from the begining. But, bad teachers made me not want
to take any more high school classes.
I can remember one science teachers who actually lost my assignments on a
few ocassions and expected me to redo them plus some. Made me furious.
And I must say most of my science books were boring, and the labs (we spent
a whole year on the metric system) were stupid.
If you want to make science interesting, take it out of the classroom.
Look at an anthill. Ask students how they would study ants in this
situation. If you are studying volcanoes show them newsreal pictures of
individuals going down into craters, tell them what sort of questions they
expect to get answered. Maybe you can ask them what they would like to be
when they grow up and relate the science to that. I know I always said I
wanted to be a Zoologist (and guess what I did.) Too bad nobody in those