Topic 1 Flashcards
What does a microscope do?
A microscope makes really tiny objects look a lot bigger so you can see them
What is a microscope slide?
A strip of thin clear glass or plastic with the material that you want to look at stuck to it.
How do you prepare a microscope slide?
- Take a sample of the cells you want to look.
- Place it in the middle of a clean microscope slide
- Use a pipette to add a drop of water or a stain to the sample.
- Carefully put a clean coverslip over the top.
Why do you need a stain?
Adding a stain makes it easier to see the cell parts. You need to use different stains depending on which bits of the cells you want to see.
What are the types of stains and their properties?
Methylene blue stains the nuclei of animal cells blue.
Iodine stains the starch molecule (in plant cells) blue/black.
Eosin Y stains the cytoplasm in all cells pink.
How do you use a light microscope?
- Place the microscope near a lamp or window and angle the mirror so light shines up through the hole in the stage. (Don’t reflect direct sunlight into the microscope or you could damage your eyes).
- Clip the slide you’ve prepared onto the stage.
- Select the lowest powered objective lens.
- Turn the rough focusing knob to move the objective lens down just above the slide.
- Look down the eyepiece lens and adjust the focus using the fine focusing knob and keep adjusting until you get a clear image of the cells on the slide.
- If you need to see the cells with greater magnification, switch to a higher powered objective lens and refocus the microscope.
What is magnification?
How many times bigger the image you can see is compared to the real object.
Equation for total magnification
Total magnification = eyepiece lens magnification x objective lens magnification
Formula for magnification
Magnification = image size/ real size
8 parts of a light microscope
- Mirror
- Stage
- High and low power objective lenses
- Body tube
- Eyepiece lens
- Rough focus knob
- Fine focus knob
- Handle
