PHYSICS BASICS INTERNATIONAL SYSTEM OF UNITS SI The

PHYSICS BASICS

INTERNATIONAL SYSTEM OF UNITS (SI) The modern form of the metric system used to standardize measurement The SI is based on the decimal system Base Units: � Length- meter (m) � Volume- liter (L) � Mass- kilogram (kg) � Time- second (s) � Temperature- kelvin (K) � Electric Current – ampere (A) � Luminous intensity – candela (cd) � Amount of substance – mole (mol) � Density: kg/m 3

SI PREFIXES 1 km = 103 m 1 m = 10 -3 km 1 cm = 10 -2 m 1 m = 102 cm 1 m. L = 10 -3 L 1 L = 103 m. L When converting to a larger unit, the decimal always goes left. When converting to a smaller unit it goes right.

CHECKPOINT How many meters (m) are in a hectometer (hm)? How many liters (L) are in a centiliter (c. L)?

SCIENTIFIC NOTATION Used to quickly express large or small numbers. The rules: � Convert to a decimal with only one significant figure in the front � Multiply by 10 X to make the terms equivalent. Ex: � 1200 = 1. 2 x 103 �. 000123 = 1. 23 x 10 -4

E NOTATION E notation is like scientific notation, and you can see it mostly on calculators We do the same thing we do with scientific notation, just replace the 10 with an E Ex: � 1200 = 1. 2 E 3 �. 000123 = 1. 23 E-4

CHECKPOINT Express 34000 in scientific and E notation Express 0. 0245 in scientific and E notation

SCIENTIFIC METHOD Purpose – state your problem as a question. What do you want to learn? What have you already observed that makes this important to you? Hypothesis – predict, based on what you have already seen or other reasonings, what you will learn during your experiment Experiment – come up with the materials and procedures you will used in the experiment, then follow them in order to collect data. Analysis/Discussion – discuss what happened during your experiment as well as any equations that describe what happened. Also point out any sources of error and include what you would do differently if you did the experiment again. Conclusion – State whether or not your hypothesis was supported and why. REMEMBER: you don’t learn from an experiment whether something is TRUE or FALSE.

SCIENTIFIC METHOD Isn’t always the same! There is no set way for how to do “science. ” Sometimes you will do research before you experiment, sometimes not. Some people think that the italicized words I had on the slide before should be steps on their own. Overall, though, there is one thing that is constant. We experiment in order to learn something new.

LET’S PRACTICE Who has a problem, something they want to know?

IMPORTANT TERMS Variables: things that can change � Independent variable: what you purposefully change � Dependent variable: what you expect to change because of the change in your Independent Variable. � Controlled variables: all other possible variables that might affect the Dependent Variable, and that you do you best to Hold Constant during the experiment. Control group: the group that you don’t do anything to (in my plant experiment, they are the ones I don’t sing or talk to).