3 microscopes

what’s the the 3 types of microscopes?

• optical (light) microscope

• transmission electron microscope

• scanning electron microscope

define magnification

how many times larger the image is compared to the object

define resolution

the ability to determine between two separate points

how does an optical microscope work?

a beam of light is condensed to create the image

what are the features of an optical microscope?

• poorer resolution due to light having a longer wavelength

• lower magnification

• colour images

• can view living samples

how does an electron microscope work?

a beam of electrons is condensed to create image (electromagnets are used to create the beam)

what are the features of an electron microscope?

• higher resolving power as electrons have a short wavelength

• higher magnification

• black and white images

• samples can’t be living as they are in a vacuum (no oxygen)

how does a transmission electron microscope work?

• thin specimens are stained and placed in a vacuum

• electron gun produces beam of electrons that pass through the specimen

• some parts absorb the electrons and appear dark

• image is 2D and shows detailed images on the internal structure of cell

how does a scanning electron microscope work?

• specimens do not need to be thin as electrons are not passing through the specimens

• the electrons are beamed onto the surface and are scattered in different ways depending on the contours

• this produces a 3D image

what’s the equation for magnification?

magnification = image size/actual size

how do you convert from meters to millimetres?

x1000

write the units from biggest to smallest

• meters

• millimeters

• micrometers

• nanometers

how do you convert from millimeters to micrometers?

x1000

how do you convert from micrometers to nanometers?

x1000

how do you convert from nanometers to micrometers?

divide by 1000

how do you convert from micrometers to millimeters?

divide by 1000

how do you convert from millimeters to meters?

divide by 1000