Hello, I am in the 7th grade do a science fair this year. I am making a vacuum cleaner, I used an average sized small plastic box, and a 12V computer fan. I also have a plastic tube that I shortened for the sake of making it not have to suck from so far away. My problem is, is that I cannot make it have enough power, I am positive it is getting 12 Volts of power from my 12V batter I got at ACE Hardware the other day. But it sucks little to nothing, I put it in backwards the way it sucks in. I am very stuck and it is due on Wednesday but I really need it done this weekend, help me please. Any thoughts or suggestions help!

It would appear that the box is too big? There is not a good seal on all parts?
The fan, running on battery is not powerful enough to created the air flow needed?

Get a bigger fan. That may require a bigger power source also.

Fans are rated in cubic feet per minute. You can't create suction unless you can move enough air, and control that air.

The fan you have is an open axial flow fan, will not develop enough static pressure. You need a closed axial like a vacuum cleaner or centrifugal fan. Plus, you need a high volume fan. A computer fan will not work.