This is a poster I made when I was teaching about properties of light. It shows a solid object (the yellow string of yarn) being placed behind different types of paper (transparent, translucent, and opaque). I cut out rectangular samples from different paper sources: clear cellophane packaging for transparent paper, waxed paper for translucent paper, and colored card stock paper for opaque paper.
Here's a quick activity that students can do to compare the degree of transparency among these different types of paper: Use three similar flashlights, a rubber-band to secure each sheet of paper over the face of the flashlight. Turn of the classroom lights to get the room dark enough, then flick on the flash lights simultaneously to shine at the wall. Your students can try this with other types of paper like tissue paper, transparency paper, recycled paper, etc, and sort these types of paper on in a table or sort them in a continuum that goes from transparent to opaque.