agenda: monday, dec 10 how small are they? magnification...
TRANSCRIPT
Agenda: Monday, Dec 10
-How small are they?
-Magnification and actual size!!
Microscopes Early microscopes
Light microscopes
Transmission Electron Microscope
Scanning Electron Microscope
Transmission electron micrograph
a bacterium
liver cell
Scanning electron micrograph
10x
10000x
10000000x
0.003
45mm
4.5 cm
Q #3 on your worksheet
Calculate the magnification of these scale bars:
Q #4 on your worksheet
21000/2=10500 times Or 20000/2=10000 times
21000/67=313 times Or 20000/67=299 times
41000000/100=410000 times Or 40000000/100=400000 times
41000/100=410 times Or 40000/100=400 times
24000/50=480 times Or 23000/50=460 times
24/50=0.48 times Or 23/50=0.46 times
0.034/500=0.000068 times Or 0.033/500=0.000066times
1. 2.
3. 4.
5. 6.
7.
MAGNIFICATION !!!
ACTUAL SIZE !!!
(measured length)
(scale bar label)
Q# 5 on worksheet
Q #6 on your worksheet
Typical IB exam question:
1. A student views an image of a cell magnified 50000
times. The image is 60mm long.
a. What is the actual length of the sample in the image?
b. Is the cell more likely to be a plant cell, animal cell,
bacterium or virus? Explain why.
c. A sperm cell has a tail 50µm long. A student draws it
50mm long. What is the magnification?
