Lesson 2: RP: Microscopes Flashcards
What is the eyepiece lens?
Where the viewer looks through to see the specimen
What is the stage?
Where the slide is clipped down.
Some cells need to be stained with iodine before being clipped down
What is the objective lens?
Changes the magnification of the image.
What is the coarse focus knob?
Moves stage up and down
What is the fine focus knob?
Used to make image clearer
What is resolution?
Resolution is the ability to distinguish between 2 points on an image ie. the amount of detail.
What is the mirror?
Reflects light from light source onto stage.
What chemical is used to make the specimen clearer in a microscope?
The orange chemical iodine.
It turns blue/black on transparent, starchy specimens.
What is the smallest magnification on the objective lens?
4x
What is the largest magnification on the objective lens?
40x
What is used to focus an image at a low magnification?
The coarse focus knob will focus an image at a low magnification.
What is used to focus an image at a high magnification?
The fine focus knob is used to focus an image at a high magnification.
What is the nosepiece?
The nosepiece will move the objective lens.
What are the 8 steps to using a microscope?
1.) Put the slide onto stage. Stain transparent cells with iodine to make visible.
2.) Turn objective lens to lowest magnification.
3.) Turn coarse focus knob to ensure slide is ALMOST touching objective lens.
4.) Look down into eyepiece
5.) Increase distance between objective lens (using CFN) and slide until cells come into focus
6.) Bring cells into focus
7.) Increase objective lens magnification
8.) Use fine focus knob to bring cells into focus.
Why do you start the objective lens on lowest magnification?
- To have a better field.
- View will be wider
- Increased number of cells seen.
Why don’t you move the stage close to the objective lens?
- Prevents slide from breaking
- Prevents blurriness
How do you calculate the overall magnification?
Overall magnification = eyepiece lensx objective lens
How do you calculate the image size?
Image size = actual size x magnification
What is the usual magnification for an eyepiece lens?
10x
What is the image size?
What the object appears to be in the microscope.
What is the actual size?
How big the object is in real life.
Give a health and safety factor from the practical.
- Be careful with glass slide
Give 2 ways you can improve this practical.
- Wear gloves: avoid cross- contamination
- Add few drops of water to avoid dehydration of cells (structures seen better.)
What are the 3 different usual magnifications of objective lens?
- 4x
- 10x
- 40x
Which one is smaller in size?
- Fine focus knob
- Coarse focus knob
- Fine focus knob is smaller
- (usually under the coarse focus knob)
