quiz laboratorio #2 Flashcards
5 objectives of the lab 2
-learn about the International System of unites (SI units)
-learn the difference between magnification, resolving power, and contrast.
-learn how to properly prepare a wet mount
-learn to identify the parts of the compound light microscope, and describe the function of each part
-learn how to properly use and take care of a microscope
the first standardized system of measurement was proposed in _____ around the year ______
France and1670
The ________ ____________ _________ is the standard system of measurement. It has been renamed __________ ____________ _______ ______()
-modern metric system
-International System of Units (SI units)
There are three major parts to the metric system:
-the seven base units
-the prefixes
-units derived from the base units.
table of units
Physical Quantity Name of unit Symbol for unit
length meter (meter) m
mass kilogram kg
time second s
electric current ampere A
temperature Kelvin K
amount of substance mole mol
luminous intensity candela cd
NON-METRIC UNITS COMMONLY USED
-Liter: symbol = L. It is generally used in science and it is used in biological publications.
-Cubic centimeter: symbol = cm3. Often used for measuring the volume of solids, one cm3
equals one milliliter (mL).
-Ångström: symbol = Å. One Å equals 10-8 cm or 10-10 m
The Meter (m)
The meter is the basic unit of length. The original definition was one ten-millionth of the distance from the
North Pole to the Equator.
From that, French scientists made a bar of 90% platinum and 10% iridium and put two marks on it to signify the meter distance. This particular alloy was used because it resisted expansions due to temperature and this reduced the error due to the width of the lines.
Today the meter is simply defined as the distance light travels
second [s]
The second is the basic unit of time.
The Kilogram (kg)
why wasn’t grams used?
the kilogram is defined using three numbers:
The kilogram is the basic unit of mass.
Until recently, it was the only basic unit still defined in
terms of a material object, and also the only one with a prefix[kilo] already in place.
- According to the International Bureau of Weights and Measures (BIPM), a kilogram was used as the original standard because a standard of one gram would have been too difficult to establish and use—due to its small mass.
-the kilogram is defined using three numbers: the constant of the Planck, and the second and the meter using the speed of the light in
the vacuum, and a fixed value of the frequency of the caesium.
ampere [A]
basic unit of:
named after
The ampere is the basic unit of electric current.
It is that current which produces a specified force between two parallel wires which are 1 meter apart in a vacuum. It is named after the French physicist Andre Ampere.
Kelvin [K]
freezin point
The Kelvin is the basic unit of temperature.
The freezing point of water is 273.15 K or 0 C.
Note, unlike the Fahrenheit and Celsius scales, kelvin is not in ⁰degrees—so it is expressed as K .
mole [mol]
a mole contains
The mole is the basic unit of substance.
It is the amount of substance that contains as many elementary units as there are atoms in 0.012 kg of carbon-126. A mole contains 6.0221415 x 1023 atoms, molecules, particles, ions, electrons, or whatever12
candela [cd]
The candela is the basic unit of luminous intensity.
It is the intensity of a source of light of a
specified frequency, which gives a specified amount of power in a given direction.
SI derived quantities
Are defined in terms of the seven base quantities via a system of quantity equations. The SI derived units for these derived quantities are obtained
from these equations and the seven SI base units.
SI derived quantities table
Volume Cubic meter m3
Area Square meter m2
Speed, velocity Meter per second m/s
Mass density Kilogram per cubic meter kg/m3
Specific volume Cubic meter per kilogram m3/kg
Magnetic field strength Ampere per meter A/m
Amount-of-substance of concentration—Mole per cubic meter mol/m3
Luminance Candela per square meter cd/m2