Microscopes help us see small objects typically less than 500 nm nm = nanometer = 1/1,000,000 mm size of a human egg size of a sharp pencil point

Magnification making an image appear larger than its actual size not actually changing the size of the object

Magnification indicated by _____ X i.e. an object that is 100X had been magnified 100 times the bottom image is 1860X

Resolution the ability to distinguish the details of an image measure of the clarity of an image

Resolution improved by adjusting the focus of a microscope resolution capability of a microscope of may be determined by an object’s size and degree of detail

Resolution often displayed as a distance a smaller distance means that a smaller object can be viewed clearly a smaller distance means the microscope has better resolution

Magnification and Resolution Both high magnification and good resolution are necessary to see small objects clearly.

Types of Microscopes Compound Light Microscopes Electron Microscopes

1. Compound Light Microscopes (CLM) more than 1 light illuminating the object for clarity light passes through two lenses to produce an enlarged image of a specimen

1. Compound Light Microscopes (CLM) magnification of an object observed using this microscope is the multiplication of the 2 (or more) lenses used to view the object What is the possible compounded magnification of these lenses?

1. Compound Light Microscopes (CLM)

2. Electron Microscopes microscopes shoot electrons at dead objects/specimens as the electrons bounce back, the energy is recorded and translated into an image

2. Electron Microscopes must be viewed in a vacuum vacuum no air no living cells can be viewed

2. Electron Microscopes There are two types of Electron Microscopes Transmission electron microscope (TEM) Scanning electron microscope (SEM)

Transmission Electron Microscope (TEM) Form 2D images TEM images are always in black and white. with the help of computers scientists add color to make things easier to see

Transmission Electron Microscope (TEM) An electron beam is directed at a slice of a specimen that has been stained with metal ions. Some structures become more heavily stained than others. Those heavily stained areas absorb electrons and in the lightly stained areas the electrons pass through hitting a fluorescent screen and forming an image on the screen.

Transmission Electron Microscope (TEM)

Scanning Electron Microscope (SEM) essentially works the same as a TEM (electron beams) shows 3D images of the surface of a specimen

Scanning Electron Microscope (SEM) sample is coated with a very thin layer of metal again, color has been added with a computer Strain of Staphylococcus aureus bacteria (20,000x)

Scanning Electron Microscope (SEM)

Comparing Magnification and Resolution Microscope Type Magnification Resolution CLM 2,000 x 200 nm TEM 50,000,000 x 50 pm SEM 500,000 x 1 nm (1 nm = 1,000 pm) nm = nanometer (1 nm =1 billionth of a meter) pm = picometer (1 pm = 1 trillionth of a meter)

Microscope Collage See Microscope Collage rubric. Other Resources to use: Textbook Pages 50 – 54