Bigger not better
Here's a quick SMART board idea to show the difference between increasing resolution and magnification. I did a similar thing today but I drew a little squiggly thing instead of a spot. Could be a bit dangerous in case the magnified squiggle turned into something inappropriate when magnified. Luckily it didn't. Over the years I have noticed how student's understanding of resolution has changed. If you mention resolution now quite a few students will mention pixel size in digital photography. In most cameras it is pixel size that is the limiting factor to resolution rather than the diffraction at the aperture, very few students would have mentioned grain size in the old days. Whilst on the digital photography theme I was thinking about that common question: "state two advantages of using a digital camera as compared to an analogue camera that uses film." Most students today have probably never used a film camera so we have to first explain what it is then give the advantages of the digital version. Seems pretty pointless to know such things. It's not as if they are ever going to have to make the choice.