A student, observing a micro-organism under a magnification of 40X, calculates that it is about 100 micrometers long. If she then draws the microorganism 2 cm long, what is the magnification of her drawing?

ANSWER First convert 100 micrometers to mm: 100 um / 1000 = 0.1 mm 1. First convert 100 micrometers to mm: 100 um / 1000 = 0.1 mm Then convert 2 cm to mm: 2 cm * 10 = 20 mm Now that we have the same unit, we can calculate drawing magnification Magnification = drawing size (which is 20 mm) divided by actual specimen size (which is 0.1mm) Magnification = 20 mm / 0.1 mm = 200X

2. A cell is observed using an SHS microscope under high power and is estimated to be about half the field of view. A student then draws the cell 25cm in length. What is the magnification of the drawing?

ANSWER 2. At SHS, our microscopes have a high power field of view of 0.45 mm. If the cell is half the field of view, it is 0.23 mm. Convert 25 cm to mm so we are using a consistent unit. 25 cm * 10 = 250 mm Now that we have the same unit, we can calculate drawing magnification Magnification = drawing size (which is 250 mm) divided by actual specimen size (which is 0.23 mm) Magnification = 250 mm / 0.23 mm = 1087 X which rounds to 1000X (or 1100X if you follow sig figs)

3. A student draws a cell diagram 24mm long, which is 400X larger than life size. How large is the actual cell?

Answer 3. This problem gives us the magnification as 400x and the drawing size (24mm). So, we rearrange the formula to be: Actual specimen size = drawing size (which is 24 mm) divided by magnification (which is 400X) Actual specimen size = 24 / 400 = 0.06 mm

4. A cell is 80 um in length. If drawn 600 times actual size, how long will the drawing be in cm?

Answer First convert 100 micrometers to mm: 80 um / 1000 = 0.08 mm 4. First convert 100 micrometers to mm: 80 um / 1000 = 0.08 mm This problem gives us the magnification as 600x and the specimen size (0.08mm). So, we rearrange the formula to be: Drawing size = magnification (which is 600X) times actual specimen size (which is 0.08mm) Drawing size = 600 times 0.08 = 48 mm The answer is needed in cm, so convert 48 mm to cm cm = 48mm/10 = 4.8 cm

Microscopy Math Practice 5 The following information is for a microscope which has an eyepiece lens (ocular lens) with a power of 10X: Using the information provided above, calculate the field diameter for medium and high power. Objective Lens Power FOV Diameter Low 4x 3500 µm Medium 10x High 40x

Answer 3500 um X 4 = 1400 um 10 3500 um X 4 = 350 um 40 Objective Lens Power FOV Diameter Low 4x 3500 µm Medium 10x 1400 µm High 40x 350 µm Answer 3500 um X 4 = 1400 um 10 3500 um X 4 = 350 um 40

Microscopy Math Practice 6 If the paramecium is viewed under medium power with an SHS microscope, what is the estimated length of one paramecium? Hint: Under low power, FOV diameter is 4.5 mm

Answers 4.5 mm X 4 = Diameter at medium power= 1.8 mm 10 ½ X 1.8 mm= .9mm= 900 um

Microscopy Math Practice 7 If the Elodea cells to the left are viewed under high power with an SHS microscope, what is the estimated length of one cell?

4.5 mm X 4 = Diameter at medium power= .45 mm 40 ¼ X .45mm = .1125 mm = 112.5 um

Microscopy Math Practice 8 viewed under 400x magnification The diameter of one drawing of a cell is 33mm. The diameter of one cell is estimated to be 60 micrometers. What is the drawing magnification? In other words, how many times larger is the drawing than an actual cell?

Answer 33mm x 1000 um = 33000 um 1mm 33000 um= 550 X magnification

Microscopy Math Practice 9 This micrograph of a liver cell is 2500X larger than life size and 60mm in diameter. What is the length of the diameter of this cell?

Answers 60 mm is 2500 times larger than the cell in real life 60mm X 1000um = 60000 um 1mm 60000 um = 24 um is the size of the cell 2500