1/5/11
Post date: Jan 04, 2011 9:5:8 PM
Bell ringer: What is a measurement? Why are measurements important?
Purchase lab books ($1.25)
Law, Hypothesis, and Theory notes
Law - a generalized pattern of consistent observations ("What goes up must come down" or later "All masses are attracted to eachother by a force of gravity dependent on the mass of each object and the distance between them")
Hypothesis - a proposed explanation based on previous observations. Hypotheses can be tested through experimentaion and supported or disproven by evidence collected. ("Certain breeds of dog are more prone to giving static shocks because they have longer hair")
Theory - An explanation of WHY something happens the way it does, with all available evidence supporting this idea. Theories are generally accepted by the scientific community at the time, but if evidence is discovered that contradicts a theory, theories can be changed or thrown out. ("The universe started out as a tiny particle, and has been expanding outward for nearly 14 billion years")
Lab safety (safety contracts due next Wednesday)
Measurements
Are a form of observation
May provide evidence to help us formulate a theory
Accurate measurements help us make more accurate theories
The SI system (the metric system)
Used everywhere except USA and Australia (and a few units in Britain)
Used in SCIENCE
Uses prefixes to make larger or smaller increments
Time (second) - related to frequency of radiation from Cs-133
Distance (meter) - distance traveled by light in a vaccuum in 1/ (299,792,458) seconds
Mass (kilogram) - mass of a platinum-iridium rod kept near Paris
Distances
How far between two points
Basic unit is the meter (m)
For small measurements, we use the centimeter (1/100th of a meter) or the millimeter (1/1000th of a meter)
For large measurements, we use the kilometer (1000 meters)
To measure distance, we can use meter sticks and rulers
Measurements and Graphing Lab
Due Thursday, 1/7/10