Cellular Theory And Microscopes By Robert Hooke Essay
Robert Hooke was an English scientist credited most famously for the creation of Hooke’s Law (a principle of physics that states that the force needed to extend or compress a spring by some distance is proportional to that distance) in 1660 and the discovery of plant cells using a compound microscope in 1663.
The compound microscope uses two or more lenses, which are connected by a hollow tube. The top lens (called the eyepiece) is the one that people look through, and the bottom lens is called the objective lens. This means that the specimen is magnified twice as much as a simple microscope.
Hooke developed his microscope with a new screw operated focusing mechanism that he had designed himself. He also improved the microscope with lighting – he placed a water lens next to the microscope, which allowed the light from the oil lamp to focus on the specimen so it could be illuminated brightly. With this microscope, he was able to observe organisms such as insects, bryozoans (aquatic invertebrate animals), bird feathers and sponges.
Hooke’s most famous observation in microscopy was undoubtedly the discovery of plant cells while studying thin slices of cork in 1663. To begin with, he had thought cork was ‘perforated’ and ‘porous’, like honeycomb, but when he began to study it, he realised that what he was looking at were in fact the first microscopical ‘pores’. Hooke had discovered plant cells – he had seen the cell walls in cork…