Measuring pcr fragments in a gel - (Jun/27/2014 )

I have two fragments (~ 1kb) , one is 7 bp larger than the other, can I run them in a denser (higher %)  agarose gel to figure out which is which? What type of concentration should i use? 

Thanks

Short answer: No.

You will never tell the difference between those fragments on an agarose gel.

Can you cut one of them into shorter fragments with an enzyme?