The Fundamental Tools Of Science Slide 2 Units Some fundamental
measurements in all of science: Length Time Mass Many others are
combinations of these: Energy, Speed, Volume, Area Slide 3 Units
International Standard Units (SI, aka metric) Length (m meter) Mass
(kg kilogram) Time (s seconds) Energy (J joules) Temperature (K
kelvin) Slide 4 Temperature Scales 1 kelvin degree = 1 degree
Celsius Notice that 1 kelvin degree = 1 degree Celsius Boiling
point of water Freezing point of water Celsius 100 C 0 C 100C
Kelvin 373 K 273 K 100 K Fahrenheit 32 F 212 F 180F Slide 5
Temperature Scales 100 o F 38 o C 311 K oFoF oCoCK Slide 6
Significant Figures: Digits in a measurement having values that are
known with certainty plus one digit having a value that is
estimated. Slide 7 Reading Volume: Significant Figures on an
Instrument Slide 8 Measurements that contain a greater number of
significant figures are more precise than measurements that contain
fewer significant figures. Always select an instrument that gives
you the most significant figures. Only report as many sig figs as
that instrument allows Slide 9 The Rules Slide 10 All numbers 1-9
are significant. Zeros are sometimes significant, here's how you
can tell: If a decimal point is present, starts on the Pacific
side, move across until you get to a 1-9 digit, and start counting
to the end If a decimal point is absent, start on the Atlantic
side, move across until you get to a 1- 9 digit, and start counting
to the end 1005 contains ? sig. Figs., 23,000 has ?, 1,045,090 has
? 40.01 has ?1.100 has ? sig figs, 0.00540 has ?, Slide 11 When
multiplying or dividing measurements: round the answer to the same
number of digits as the measurement having the fewest number of
significant figures. When adding or subtracting measurements: round
the answer to the same number of decimal places as the measurement
having the fewest number of decimal places. Slide 12 Identify the
LEAST PRECISE measurement. Identify the MOST PRECISE digit (place)
within that measurement. Round the answer to this digit (place).
123456.7890 Higher precision Lower precision Slide 13 Conversion
Commonly Used Prefixes: kilo = 1000 of something ( 1km= 1000m, kg)
deci =0.1 of something (10 dm = 1m) centi = 0.01 of something (100
cm = 1m) milli = 0.001 of something (10 3 mm = 1m) micro = 0.000001
(10 6 m = 1m) nano = 0.000000001 (10 9 nm = 1m) pico =
0.000000000001 (10 12 pm = 1m) Refer to Conversion Chart to
additional prefixes Slide 14 All conversion factors are fractions.
Conversion 100 cm 1 m 100 cm 1m 10 -6 m == 1 = 1m 10 -6 m 1 km 10 3
m == 1 10 3 m Slide 15 Units are multiplied and divided like
numbers are. The Nature of Units 10 meters 2 meters = 5 (the units
cancel out) 50 miles 10 gallons = 5 miles/gallon (the units combine
as a fraction) 10 meters x 10 meters x 10 meters = 10 3 m 3 (the
units combine as exponents) Only IDENTICAL UNITS on 2 numbers can
be added or subtracted. The answer always has the same units. 100
kg 25 kg = 75 kg 100 kg 25 m = Meaningless Dribble Slide 16 How
many seconds are in 54 days? Write the measurement with its unit.
If it isnt already a fraction, write it over 1. Set up conversion
factors that Cancel units you want to get rid of Replace with units
you are looking for Have values on the top and bottom that are
equivalent Multiply numbers across the top Multiply numbers across
the bottom Divide to get answer, check units Slide 17 Scientific
Notation 10000000000000000000000 0.00000000000000000000000000001
There has to be a better way to write those numbers Rules for
scientific notation 1) Always express the number starting with the
ones place followed by any decimal digits, times a power of 10.
2)To express a large number, count the number of decimal places
needed to move to the onesplace, and make that number the exponent
of ten. 3) To express a very small number, count the number of
decimal places needed to move to the ones place, and make that
number the NEGATIVE exponent of ten. 4) After re-expressing the
number in scientific notation, check it by writing out the expanded
ten, and multiply it by the measured number. Slide 18 Scientific
Notation Examples: 0.000000000000000000000000000000001 = 1.0 x 10
-35 94140000000000000000000000000000000 = 9.414 x 10 35 Slide 19
Slide 20 20 Accuracy how close a measurement is to the true value
Precision how close a set of measurements are to each other
accurate & precise but not accurate & not precise Slide 21
Precise if they give many significant digits Accurate if calibrated
to a standard Slide 22 To report the accuracy of your measurements
Observed True True X 100 Slide 23 To report the precision of your
measurements 1 2 3 Average your measurements Find the absolute
values of the differences between each measurement and the average
Average these differences
