Chapter7 Microscopes and cells

Microscopes reveal cell structure Robert Hooke , an English scientist, invented the microscope in the 1600’s to view cork He named the “little boxes” he saw, “cells” – plant cell

Anton van Leeuwenhoek Used a microscope to view pond water He named the single-celled organisms he discovered “animalcules”

Measuring the size of cell structures Measurements are in metric units Micrometers are one-millionth of a meter ( the size of a bacterial cell)

Characteristics of microscopes Magnification vs. Resolution makes an image -makes an image appear larger than appear more or less its actual size clear BOTH are needed to view the details of extremely small objects clearly

Different types of microscopes Light microscopes Electron Microscopes Light passes through uses a beam of electrons one or more lenses to form an image to produce an enlarged image

Compound Light Microscope Used in high school labs Most powerful magnifies 2,000x Can view live specimens Much less powerful than electron microscope

Electron Microscopes Can magnify up to 200,000x No live specimens can be viewed

Rules when using the Microscope Carry the microscope by the arm and base. Place the microscope 4 – 6 inches from the edge of the lab table. Do not use the coarse adjustment when on high power.

Field of View 3 things to include in a Microscope drawing: Title At least 1 label Total magnification