M ICROSCOPES How to Use a Microscope Microscope Drawings Parts of the Microscope Magnification, Resolution and Contrast Types of Microscopes

H OW TO U SE A M ICROSCOPE see handout for complete list carry microscope with care using two hands only use coarse adjustment on LOW power return microscope with stage as low as possible, LOW power lens in place and power off

M ICROSCOPE D RAWINGS see handout for complete list use pencil and white paper use a ruler for all labels and place them on the right of the drawing use appropriate size and scale stippled when required

P ARTS OF A C OMPOUND L IGHT M ICROSCOPE 1 – eyepiece/ocular – contains the magnifying lens to look through 2 – body tube – holds the lenses of the eyepiece and the objectives at a set distance from each other 3 – high-power magnification lens – used to magnify the specimen 40 x and see a small area with lots of detail

P ARTS OF A C OMPOUND L IGHT M ICROSCOPE 4 – low-power magnification lens –used to magnify the specimen 4 x and see a large area with little detail 5 – stage clip – holds the slide in place 6 – stage – holds the slide and a hole in the center admits light 7 – diaphragm – regulates the amount of light that passes through the hole and the specimen

P ARTS OF A C OMPOUND L IGHT M ICROSCOPE 8 – base – supports the weight of the microscope 9 – arm – supports the body tube and adjustments and allows the microscope to be carried 10 – coarse adjustment knob – used to get the specimen in focus

P ARTS OF A C OMPOUND L IGHT M ICROSCOPE 11 – fine adjustment knob – used to focus through the layers of the specimen 12 – revolving nosepiece – holds the objective lenses and permits their interchange 13 – light source – emits light through the diaphragm

M AGNIFICATION amount the lens enlarges the specimen in a compound light microscope both the eyepiece and the objective lenses magnify the specimen total magnification is the amount of magnification seen when looking through both lenses total magnification = eyepiece magnification x objective magnification

M AGNIFICATION Calculate the total magnification for the school microscopes: Eyepiece Magnification Objective Lens Magnification Total Magnification 10 x4 x (Low Power) 10 x10 x (Medium Power) 10 x40 x (High Power)

R ESOLUTION how well a microscope allows you to make out two different objects that are very close together most people can see with a resolution of 0.1 mm or larger microscopes allow us to see with a higher resolution

C ONTRAST how well you can tell the difference between cell parts or the cell and the background to improve contrast scientists will stain cells stains allow scientists to see the cell against the background of light most common stains used are methylene blue and iodine

S IMPLE L IGHT M ICROSCOPES uses one magnification lens beam of light travels through the specimen living organisms movement true colour magnification of 1000x

S IMPLE L IGHT M ICROSCOPE

C OMPOUND L IGHT M ICROSCOPES uses two magnification lenses beam of light travels through the specimen living organisms movement true colour magnification of 2000x resolution of 200 nm

C OMPOUND L IGHT M ICROSCOPE

P ARAMECIUM C ELLS – L IGHT M ICROSCOPE

C HEEK C ELL – L IGHT M ICROSCOPE

S TEM CELLS – L IGHT M ICROSCOPE

T RANSMISSION E LECTRON M ICROSCOPE beam of electrons travel through the specimen only very thin specimens specimens are encased in plastic and the plastic is shaved to get the thickness required dead organisms magnification of x resolution of 0.2 nm

E LECTRON M ICROSCOPE

C ELL – T RANSMISSION E LECTRON M ICROSCOPE

S CANNING E LECTRON M ICROSCOPE electrons scan the surface of the specimen and are reflected and magnified onto a screen to produce an image image is 3-D magnification and resolution lacking compared to transmission microscope better contrast and depth than the transmission microscope magnification of x resolution of 10 nm

A N T – S CANNING E LECTRON M ICROSCOPE

E GG CELL AND F OLLICLE – L IGHT M ICROSCOPE

E GG C ELL AND S UPPORT C ELLS – S CANNING E LECTRON

S PERM – LIGHT M ICROSCOPE

S PERM ON THE E GG C ELL – S CANNING E LECTRON