Scientific Measurements All measurements must have a number

Scientific Measurements • All measurements must have a number and a unit unless otherwise specified

Quantity Base Unit Mass Grams (g) Volume Liter (L) Distance Meter (m) Temperature Kelvin (K) Time Seconds (s) Measuring Tool Balance Graduated cylinder Meterstick Thermometer stopwatch

Scientific Measurements • Accuracy – A measurement of how closely individual measurements agree with the correct value – Ex. • Correct Value- 0. 55 grams • Experimental Values- 0. 54 grams, 0. 57 grams, 0. 60 grams • The most accurate value is 0. 54 grams because it has a deviation of + 0. 01.

Scientific Measurements • Precision – The closeness of agreement among several measurements of the same quantity – Ex. • Correct Value- 0. 55 grams • Experimental Values- 0. 61 grams, 0. 62 grams, 0. 60 grams • Values are not accurate but they are precise.

Scientific Notation A short-hand way of writing large numbers without writing all of the zeros.

The Distance From the Sun to the Earth 93, 000

Step 1 • Move decimal left • Leave only one number in front of decimal

Step 2 • Write number without zeros

Step 3 • Count how many places you moved decimal • Make that your power of ten

The power of ten is 7 because the decimal moved 7 places.

• 93, 000 --Standard Form • 9. 3 x 107 --Scientific Notation

Practice Problem Write in scientific notation. Decide the power of ten. 1) 2) 3) 4) 10? 98, 500, 000 = 9. 85 x 64, 100, 000 = 6. 41 x 10? 279, 000 = 2. 79 x 10? 4, 200, 000 = 4. 2 x 10? 9. 85 x 107 6. 41 x 1010 2. 79 x 108 4. 2 x 106

More Practice Problems On these, decide where the decimal will be moved. 1) 734, 000 = ______ x 108 2) 870, 000, 000 = ______x 1011 3) 90, 000, 000 = _____ x 1010 1) 7. 34 x 108 2) 8. 7 x 1011 3) 9 x 1010

Complete Practice Problems Write in scientific notation. 1) 50, 000 2) 7, 200, 000 3) 802, 000, 000 1) 5 x 104 2) 7. 2 x 106 3) 8. 02 x 1011

Scientific Notation to Standard Form Move the decimal to the right 3. 4 x 105 in scientific notation 3. 40000 --- move the decimal 340, 000 in standard form

Write in Standard Form • 6. 27 x 106 • 9. 01 x 104 • 6, 270, 000 • 90, 100

Scientific Measurements • Units can be combined – Mi/hr – m/s – g/m. L • Mi/hr = miles divided by hours

Scientific Measurements When multiplying fractions, if unit or number in the numerator and the denominator is the same, then they cancel out = = 4

Scientific Measurements

Solving for Variables • Variable must be – By itself – In the numerator – Ex. D=m/v • Solving for D because it is by itself and in the numerator

Solving for Variables • By adding, subtracting, multiplying, and dividing, isolate the variable you are solving for on one side • Remember whatever you do to one side, you must do to the other side.

Solving for Variables Solve for mass using this equation:

• PV=n. RT – Solve for V – Solve for R • . – Solve for m – Solve for v