THE
MICROSCOPE
Eyepiece:
this is where you place your eye to see a magnified image of your specimen.
The eyepiece is a small glass lens that usually has a magnifying power of 10
times. If you used the low power objective below, then the total magnification
is 10 times 4, which is 40 times bigger. If you used the high power objective,
usually 40 times, then you have magnified the image 400 times bigger than normal!
Course
adjustment knob: Turn this knob to move the stage closer or further from
the objective lens. This in turn makes the image you see at the eye piece sharp
and clear.
Mirror:
We need a bright beam of light to pass through our specimen so we can see all
the details of what it is made up off. We can bounce sunlight coming in from
a window up towards the stage by adjusting the tilt of the mirror.
Low
power objective lens: This usually magnifies objects on the stage 4 times
bigger than normal. If you use a 10 times eyepiece, it magnifies the 4 times
image to a TOTAL of 40 times its original size.
High
power objective lens: This usually magnifies objects on the stage 40 times
bigger than normal. If you use a 10 times eyepiece, it magnifies the 40 times
image to a TOTAL of 400 times its original size! Some microscopes have one more
objective that magnifies 100 times. The TOTAL magnification with the eye piece
is then 1000 times, the best a light microscope can do.
Stage:
We place a glass slide with our specimen onto this platform. Light from the
mirror below will pass through the stage and through the object on the slide.
Light carries on up to the objective lens forming an image that can be magnified
further by the eye piece lens.
Barrel: Light from
the objective lens that is already magnified carries on up to a second magnifying
lens in the eye piece.
The eye piece lens magnifies
the image further.
Rotating
nose piece: to
change the objective lens we want to use, we just twist this piece around to
the lens we want. The image we see in the eyepiece is largest with the high
power lens and smallest with the low power lens. We use the low power lens to
quickly find something interesting to look at. Use the high power lens to carefully
examine the detail of a specimen.
Arm:
we use this part
to carry the microscope from one place to another. Don't forget to support the
base of the microscope with the other hand!
If I use a 12X eyepiece and a 10X objective, the TOTAL magnification is
12 x 10 = 120 times.
We can only magnify up to 1000 times using a light microscope. Look at the
Electron Microscope pictures to find out
which was magnified the most.
Give the name and function of the parts of the microscope...
Stuck? Place your mouse over a part and all will be revealed...
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