1. Biological Measurements
The Metric System
&
The Microscope

2. Metric System International system of measurement
Le Systeme d’Internationale
What’s the benefit of the metric system?
Base Units
Volume: __________
Length: ___________
Mass: ___________
Temperature: __________

3. Deka milli
Hecto nano
Kilo micro
deci centi
Base

4. How many meters are in 2 kilometers?
Convert 20,000 micrograms to centigrams
Add the following measurements in meters: 10 Km, 2m, 1000mm, 5,000,000nm

5. Metric Conversions Identify the prefixes (k, c, m, µ)
Determine what direction you will move in
If you are going to a “bigger” prefix, the # will get smaller (decimal moves to the left)
If you are going to a “smaller” prefix, the # will get bigger (decimal moves to the right)
Move the decimal the appropriate places
You can compare the powers of ten to know
kilo = 103 to milli = 10-3 = total 6 places when you subtract

6. Tools & Procedures Microscopes Simple Compound Light Electron
Transmission Electron Microscope
Scanning Electron Microscope

8. Compound Light Microscope
Series of lenses that use light to magnify images (usually 1000x)
Can study dead or live organisms, no smaller than 2um.
Used in conjunction with chemical stains & fluorescent dyes to enhance images

9. Electron Microscopes Use beams of electrons to produce images
Up to 1000x more detailed than light microscopes
Cannot observe living specimens
Slides must be in a vaccuum
Two main types:
SEM: scanning electron microscope
TEM: transmission electron microscope

10. T.E.M.
Human Cornea
Rat Liver Cells

12. Practice Problems Convert the following:
454 milligrams (mg) to g
5.0 x 10-9 meters (m) to micrometers (m)
175 pounds (lbs) to ounces (oz) and to grams (g)
85C to F
A piece of aluminum foil is centimeters (cm) thick. What’s it’s thickness in micrometers?
What is the mass in grams of 1.00 gallon (gal) of water, if 1 milliliter (mL) of water has a mass of 1 gram (g)?
A pollen grain measured under the microscope appears to be 1.5 mm in diameter. How many nanometers (nm) is that?