Biological Measurements The Metric System & The Microscope
Metric System International system of measurement Le Systeme d’Internationale What’s the benefit of the metric system? Base Units Volume: __________ Length: ___________ Mass: ___________ Temperature: __________
Deka milli Hecto nano Kilo micro deci centi Base
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
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
Tools & Procedures Microscopes Simple Compound Light Electron Transmission Electron Microscope Scanning Electron Microscope
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
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
T.E.M. Human Cornea Rat Liver Cells
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) 85C to F A piece of aluminum foil is 0.00008 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?