Praxis 5440: Measurements, Materials, People

SI (International System of Units)

almost globally accepted units of measurement (ex. metric system -- meters, liters, grams etc.) that the U.S. has NOT accepted.

MKS

meters-kilograms-seconds (measurement system considering those the basic units of measurement)

deka- (da)

10x the base unit (ex. _____meter=10 meters)

hecto- (h)

100x the base unit (ex. ______liter=100 liters)

kilo- (k)

1000x the base unit (ex. _____gram=1000 grams)

deci- (d)

1/10th of the base unit (____meter=tenth of a meter)

centi- (c)

1/100th of the base unit (_____meter=hundredth of a meter)

milli- (m)

1/1000th of the base unit (_____second=thousandth of a second)

ampere (A)

used to measure electric current ("amps")

kelvin (K)

used to measure thermodynamic temperature

mole (mol)

used to measure amounts at a molecular level

random error

results in data points that may be super different from the rest of the data (do not affect the average)

systematic error

errors that show up consistently across a data set (may be due to flaws in the experiment's design)

Bunsen burner

Tuck in clothes, tie back hair, wear goggles and aprons when using. Stuents must know where safety shower and eye wash centers are.

Where should flammable liquids be stored?

away from acids, bases, and oxidizers

MSDS

Material Safety Data Sheets (tell how to handle hazardous materials)

pipettes

measure small amounts of liquid

Erlenmeyer flasks

flask with shorter neck for measuring

volumetric flasks

flask with longer neck for measuring

graduated cylinders

measurements more accurate than with flasks or beakers

burette/buret

glass, used to dispense liquid (like a skinny graduated cylinder with a tip and stopper)

SEM (scanning electron microscope)

provides greater detail than other microscopes

electronic balance

most accurate type of balance

triple-beam balance

type of balance using three beams and a plate to hold the item being weighed

spring balance

type of balance using a spring (item being weighted hangs from the spring)

chromatography

lab technique used to separate/analyze mixtures

centrifugation

spinning process to separate materials (simple example: salad spinner that separates water from salad leaves. Also: separating blood cells and plasma.)

electrophoresis

process where molecules are separated using electrical charges

calorimetry

used to determine the heat released or absorbed in a chemical reaction

titration

helps determine the precises endpoint of a reaction (so you know exactly how much of a chemical reactant to use in the experiment)

field study

experiment/study done "in the field" instead of in the classroom

Charles Darwin (died 1882)

person: survival of the fittest, natural selection

Anton van Leeuwenhoek (died 1723)

made homemade magnifying glasses and became first person to observe single-celled organisms

Carl Linnaeus (died 1778)

created system by which we classify plants and animals (called the Linnaeus Taxonomy); helped us organize and therefore study larger amounts of data

Barbara McClintock (died 1992)

created the first genetic map (for maize/corn), and was able to demonstrate basic genetic principles about cells and chromosomes

Gregor Johann Mendel (died 1884)

known as the "father of genetics." Famous for experimenting w/ pea plants to observe inherited traits.

James Watson and Francis Crick (2004)

co-discoverers of the structure of DNA, which has a "double helix" shape

mean

average

median

middle number in a list of numbers sorted from least to greatest

mode

the value appearing the MOST in a data set

range

the difference between the highest and lowest numbers

standard deviation

measures the variability of data and determines how confident one can be in the conclusions drawn