studying cells

magnification?

how many times larger the image is compared to the object

resolution?

minimum distance in which 2 objects can be distinguished as separate

how do optical microscopes work?

beam of light condensed to create image

features of optical microscope?

low resolution
smaller organelles not visible
low mag
colour image
living samples used

why is the resolution of an optical microscope lower?

light beams have shorter wavelengths

how do electron microscopes work?

beam of electrons condensed by electromagnets to make image via

features of electron microscopes?

high resolution
high mag
black + white image
sample put in vacuum + stained, so non-living

use of TEM?

thin specimen stained + put in vacuum
electron gun produces beam that passes through specimen
denser parts absorb the beam + appear darker
detailed 2D image with internal structures

use of SEM?

specimen doesn’t need to be thin but vacuumed
e- beam projected onto surface + reflected/scattered forming image
3D image with no internal structures

m → mm

x1000

mm → um

x1000

um → nm

x1000

m → nm order?

m
mm
um
nm