I wished to show weight through an ingrained concept, hence I photographed an elephant which is something all of us equate with great weight. I did try, though, to be somewhat less obvious!
Heavy: ISO 800 300mm f11 1/160
"Light" proved to be somewhat more troublesome and I was about to give up on this pair of contrasts when an opportunity arose to photograph some street performers who were "blowing" giant bubbles! In my mind I wanted to show something which was lighter than air and this fitted the bill: