Definition
An "ultramicroscope" is a microscope that uses the Tyndall effect to view particles that are too small to be seen with an ordinary microscope. It illuminates the sample from the side, causing the particles to scatter light. Think of it like seeing dust motes in a sunbeam. The particles themselves aren't directly visible, but the scattered light reveals their presence. It's useful for observing colloids and nanoparticles.