Topic: Microscopes
Magnification - There are 3 different types of microscopes:
How much bigger - Light microscopes
the image is - Electron microscopes
compared to the - Laser confocal microscopes
real life object
Magnification - How much bigger the image is compared to the real
Resolution - The life object
ability to
distinguish Resolution - The ability to distinguish between two objects that are
between two close together
objects that are
close together Magnification = Eyepiece lens x Objective lens
Parts of the microscope:
Eyepiece lens - Lens closest to the eye
Objective lens - Has 3 lenses with
different magnifications which can be
used to magnify further
Stage - Where the slide is placed, held in
place by clips
Diaphragm - Controls the amount of light
that goes onto the slide
Fine focus knob - Used to focus the
image so it is very sharp and clear
Coarse focus knob - Used to focus the
image so it can be seen clearly
Electron There are two types of electron microscopes:
microscopes use - Transmission electron microscope (TEM)
electron beam - Scanning electron microscope (SEM)
wavelength
Transmission electron microscope:
This beam of This beam of electrons is transmitted through the specimen
electrons is
transmitted Advantages:
through the - Give high resolution images with high magnification
specimen - Allows internal structures of organelles to be seen
Disadvantages:
- Can’t be used on live specimen as all water must be removed
- Only on thin specimen
- Lengthy process
- Do not produce coloured images
Scanning electron microscope:
SEMs direct a SEMs direct a beam of electrons at a specimen, electrons and X-rays
beam of electrons are ejected from the sample which are detected to form an image
Magnification - There are 3 different types of microscopes:
How much bigger - Light microscopes
the image is - Electron microscopes
compared to the - Laser confocal microscopes
real life object
Magnification - How much bigger the image is compared to the real
Resolution - The life object
ability to
distinguish Resolution - The ability to distinguish between two objects that are
between two close together
objects that are
close together Magnification = Eyepiece lens x Objective lens
Parts of the microscope:
Eyepiece lens - Lens closest to the eye
Objective lens - Has 3 lenses with
different magnifications which can be
used to magnify further
Stage - Where the slide is placed, held in
place by clips
Diaphragm - Controls the amount of light
that goes onto the slide
Fine focus knob - Used to focus the
image so it is very sharp and clear
Coarse focus knob - Used to focus the
image so it can be seen clearly
Electron There are two types of electron microscopes:
microscopes use - Transmission electron microscope (TEM)
electron beam - Scanning electron microscope (SEM)
wavelength
Transmission electron microscope:
This beam of This beam of electrons is transmitted through the specimen
electrons is
transmitted Advantages:
through the - Give high resolution images with high magnification
specimen - Allows internal structures of organelles to be seen
Disadvantages:
- Can’t be used on live specimen as all water must be removed
- Only on thin specimen
- Lengthy process
- Do not produce coloured images
Scanning electron microscope:
SEMs direct a SEMs direct a beam of electrons at a specimen, electrons and X-rays
beam of electrons are ejected from the sample which are detected to form an image
