i was looking over science fair projects and it said i needed a 'tap'?
It depends what the project is if you have to put threads like for a bolt in the project that's what a tap does .it cuts the treads you will need to make sure you get the right size . They come in many sizes.
In england a tab is the thing in the kitchen what you get water from (forset)
lol woww, i didnt know that! haha