im doing a bio project that was give out yesterday. i have everything done except for 6 questions. it sounds like a lot but its nothing compared to what i did. The questions are about microscopes. I missed that lesson and i told my teacher but she said too bad.
so i come to your help nice people, please help me with these 6 questions.
1. Locate the diaphragm under the stage of the microscope. Move it and record the changes in light as you do so. (there are 5 intesities, 1 lowest - 5 highes)
2. Why is the correct use of the diaphragm important?
3. A penny is an opaque object. Why can't you observe such opaque objects readily without a compound microscope.
4. What is meant by resolution with respect to the microscope?
5. Why must one avoid the coarse adjustement knob to focus under high power?
6. Why is the resolving power just as important as mignifying ability in a microscope?
7. Duz resolution increase wit an increase in magnific when using a light microscope?
2006-10-25 12:19:53 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Biology
Please ppl. i need answers to my questions...any one of them, even if it's just one answer....it will help!
2006-10-25 12:25:33 · update #1
1. Locate the diaphragm under the stage of the microscope. Move it and record the changes in light as you do so. (there are 5 intesities, 1 lowest - 5 highes)
When the iris diaphragm is fully open the image is flooded with light and definition is lost due to ‘white-out’. As the diaphragm is closed controlling the amount of light passing through the condenser the image is darkened and outlines appear thickened and defined as more contrast is achieved.
3. A penny is an opaque object. Why can't you observe such opaque objects readily without a compound microscope.
The basic compound microscope that many amateurs like myself use is primarily designed for use with transmitted light. Thus thin and/or transparent specimens are studied on a microscope slide and lit from below. However, there is a wide variety of subjects that can be studied by top lighting (incident lighting). These include opaque or solid subjects that cannot be viewed by transmitted light such as minerals, textiles, coins, printing, whole flowers or insects etc.
4 . What is meant by resolution with respect to the microscope?
[Resolution: the minimum distance (D) that enables two objects to be distinguished, where D = 0.61l/(Nsina). Resolution (resolving power) - The least distance between two points or lines at which they are seen as two, rather than a single blur. The greater the numerical aperture the greater the resolution.
5. Why must one avoid the coarse adjustement knob to focus under high power?
This method of focusing avoids damage to the specimen.
6. Why is the resolving power just as important as mignifying ability in a microscope?
Magnification is how much an image is enlarged under a microscope. Resolution is the amount of detail you can see in an image. This is also known as the resolving power.
7. Duz resolution increase wit an increase in magnific when using a light microscope?
Using a microscope with a more powerful magnification will not increase this resolution.
2006-10-25 13:08:50 · answer #1 · answered by forge close folks 3 · 0⤊ 0⤋
For some of the information I would look at http://en.wikipedia.org/wiki/Microscopy which explains how light microscopy works.
For a diagram of the microscope that shows its working parts:
http://sciencespot.net/Media/microparts.pdf
With a conventional bright field microscope, light from an incandescent source is aimed toward a lens beneath the stage called the condenser, through the specimen, through an objective lens, and to the eye through a second magnifying lens, the ocular or eyepiece. We see objects in the light path because natural pigmentation or stains absorb light differentially, or because they are thick enough to absorb a significant amount of light despite being colorless. A Paramecium should show up fairly well in a bright field microscope, although it will not be easy to see cilia or most organelles. Living bacteria won't show up at all unless the viewer hits the focal plane by luck and distorts the image by using maximum contrast.
A good quality microscope has a built-in illuminator, adjustable condenser with aperture diaphragm (contrast) control, mechanical stage, and binocular eyepiece tube. The condenser is used to focus light on the specimen through an opening in the stage. After passing through the specimen, the light is displayed to the eye with an apparent field that is much larger than the area illuminated. The magnification of the image is simply the objective lens magnification (usually stamped on the lens body) times the ocular magnification.
Students are usually aware of the use of the coarse and fine focus knobs, used to sharpen the image of the specimen. They are frequently unaware of adjustments to the condenser that can affect resolution and contrast. Some condensers are fixed in position, others are focusable, so that the quality of light can be adjusted. Usually the best position for a focusable condenser is as close to the stage as possible. The bright field condenser usually contains an aperture diaphragm, a device that controls the diameter of the light beam coming up through the condenser, so that when the diaphragm is stopped down (nearly closed) the light comes straight up through the center of the condenser lens and contrast is high. When the diaphragm is wide open the image is brighter and contrast is low.
A disadvantage of having to rely solely on an aperture diaphragm for contrast is that beyond an optimum point the more contrast you produce the more you distort the image. With a small, unstained, unpigmented specimen, you are usually past optimum contrast when you begin to see the image.
2006-10-25 12:34:56 · answer #2 · answered by Suedoenimm 3 · 0⤊ 0⤋
5. The high resolution objective is long and will be really close to your slide. You will smash it into your slide if you use the coarse adjustment knob.
Below is a link to a page with a diagram of a microscope.
Also a link to resolution and magnification.
2006-10-25 12:31:44 · answer #3 · answered by Shanna J 4 · 1⤊ 0⤋
3. The light is below the objects on the microscope, since it is opaque the light will not go though it and wil be blocked by the penny not allowing you to see it.
2006-10-25 12:31:44 · answer #4 · answered by flangel80190 2 · 0⤊ 0⤋
Hi. Number 4. The resolution of ANY optical instrument is limited by the physical properties of light, and determines how much detail is possible to see.
2006-10-25 12:24:54 · answer #5 · answered by Cirric 7 · 1⤊ 0⤋
Hi Girly!!!
Wow... sorry. I'm 25 and last time I had Bio was in 10th grade!!!! Yikes! I don't know ne of these!!!
My suggestion, tho, is, did you try typing these on yahoo or something? See what comes up??
Good Luck!
2006-10-25 12:36:12 · answer #6 · answered by CC88 2 · 0⤊ 0⤋
They probably meant never take a piercing gun to your own ear. Claire's has pierced millions of ears, so if there was a problem with the way they did it, you would likely know about it.
2016-05-22 13:59:05 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Well if your teacher can be that rude to tell you that.......get your own back!
When he says "you aint done your homework" reply with " i told you miss/sir that i missed that lesson, so........TOO BAD"!!
If you take this onboard then i hope i dont get you into too much trouble but what i jerk!!!!
2006-10-25 12:34:00 · answer #8 · answered by Anonymous · 0⤊ 1⤋
WOW! Horrendous! I'm glad I've left school! And I did 'A' level biology!!!!!!! :-(
2006-10-25 12:23:14 · answer #9 · answered by Pixxxie 4 · 0⤊ 2⤋
tell teacher you dont care either while glaring and have columbine written on your forehead
2006-10-25 12:23:54 · answer #10 · answered by Anonymous · 1⤊ 4⤋