iam doing a science fair on manometer?

Question

what are things i should do?

Answer 1

It depends what you are attempting to show. If you're just explaining how it works, that's one thing, but if you're looking for unique applications you might have to get creative.

Are you looking for how it works? You can explain that fairly easily.

Some interesting experiments on-line, just to stir your creative juices (you're not going to copy someone, are you?) include
http://www.science-house.org/student/bw/flight/lift.html or
http://www.ncsta.org/reflector/summer03/air.html

Since you're working with a manometer, you can explain pressure. That gives you a wider array of things to show and do, and you can think up a lot of things it applies to. Simple pressure experiments may be associated with your manometer display.