Microscopes Section 4.2

Learning Objectives Explain the relationship between a microscopes magnification and resolution Identify the two main types of microscopes and what each one is used for Identify two different types of electron microscopes

Unit Conversion Chart (Don’t Have to Copy This!)

Cells Are Microscopic Most cells are 10-20 µm (micrometers) Can’t see with just your eyes Microscopes are used to observe cells Magnification = ratio of the size of the image seen with the microscope to the actual size of the object Resolution = ability to distinguish fine detail in an image Depends on the quality of the lenses & wavelength of the light used

2 Main Types of Microscopes Light Microscope Electron Microscope

Light Microscope Curved glass lenses bend and focus light that passes through and object & creates a magnified image Also called a compound microscope because it uses multiple lenses Can only magnify objects about 1,000 times Has a resolution of about 2𝜇m Used to see living organisms

Parts of a Light Microscope (Put on Diagram Page!)

Parts of a Light Microscope (Put on Diagram Page!) Eyepiece Arm Objectives Stage Course Adjustment Fine Adjustment Lamp Base

Electron Microscope Use magnetic fields to focus a beam of electrons onto an object Images are black & white, but can be artificially colored Resolution of 2 nm Can’t see living things with it The object is placed in a vacuum

2 Types of Electron Microscopes Transmission electron microscope (TEM) Used to study the internal details of a cell Scanning electron microscope (SEM) Used to study surface structure of cells Makes a 3-D looking image