The James Webb Telescope just took a photo of a newly discovered exoplanet. Exciting stuff but the raw image just looks like a small, faint dot—not a fully detailed world. The question is, just how big would a telescope need to be to...

Howcast - Learn about pixel resolution from commercial photographer Dan Bracaglia in this digital photography lesson from Howcast.

It explains the basic principle of working of a compound microscope and lists various types of microscopes used to view biological material.

View, Learn, Share, this National Science Foundation webcast.