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“Scientific Measurement”
Measurements - AnswerQuestions: 1. What is the purpose of a measurement?2. Why are measurements important to
science?
MeasurementsMeasurements are fundamental to scienceMeasurements may be:a. Qualitativeb. Quantitative
Measurements
Qualitative Measurement: is a non-numerical measurement
Example: The solution turned brown when ammonia was added to iron (III) chloride
Quantitative Measurements
Quantitative Measurements: consist of two parts
a. A numberb. A unit
Quantitative MeasurementsExample: The rock has a mass of 9 kg
unit
Number
Practice: Classify as qualitative or quantitative
1. Water is a liquid
2. The temperature was 9°C.
3. The book is 12 cm long
Scientific NotationOccasionally some measurements are really
small or exceptionally large1, 400, 000 km, the distance to the sun0.000 000 000 066 7, the Universal
Gravitation ConstantTo help you use these, you may express
them in scientific notation
Scientific Notation ContinuedIn scientific notation, a number is written
as the products of two numbers:a coefficient and some power of 10
Scientific Notation ContinuedThe general form for scientific notation is:M x 10n where M is 1 but < 10n is an integer and exponent{integers must be a positive or negative
whole number}
Rules for Scientific Notation
1. Determine “M” by moving the decimal point in the original number to the left or to the right so that only one non-zero digit remains to the left of the decimal
Rules for Scientific Notation
2. Determine “n” by counting the number of places that the decimal point was moved. If the decimal was moved to the left, n is positive; if the decimal is moved to the right, n is negative
Guided Practice
Express the following in scientific notation:1, 400, 000 km, the distance to the sun0.000 000 000 066 7, the Universal
Gravitational Constant
Independent PracticeExpress the following in scientific notation:a. 85 000 000b. 0.000 9c. 74 000d. 0.000 005e. 30 000 000f. 864 000
Express the following scientific notations in the long form1. 7 x 104
2. 5.3 x 104
3. 7 x 10-5
4. 4.21 x 1010
5. 47 000 x 105
1. 70 0002. 53 0003. 0.000 074. 42 100 000 0005. 4 700 000 000
Express the following in scientific notation
A. 500 008B. 0.001 008 2C. 456
SI SystemThe SI system used prefixes “Kilo-” means 1000; symbol is k“Centi-” means 0.01; symbol is c“Milli-” means 0.001; symbol is m“Deci-” means 0.1; symbol is d
MOST IMPORTANT CONVERSIONS
1000 grams (g) = 1 kilogram (kg)1 mL= 1 cm3
LengthLength is the distance
between two points
UNIT: meter (m) or centimeter (cm)
Rulers and Meter Sticks measure length
Volume
Volume is the amount of space an object occupies
UNIT: L, mL, or cm3
Remember 1 cm3 = 1 mL
Volume = length x width x height (solid)Graduated Cylinders measure volume
(liquid)
MassMass is the amount of matter that
an object contains
UNITS: g or Kg
*Remember 1000 g = 1 kg
Mass and WeightMass doesn’t change
Weight does change
Weight is the force that the Earth exhibits on a mass. Weight is measured in Newtons (N).
Time
Time is the interval between two events
UNIT: second (s)
TemperatureTemperature is the measure of the
average kinetic energy of particles
Temperature measures how hot or cold an object is
UNIT: Degrees Celsius (°C)
Reading temperature on a thermometer Smart board activity
MEASUREMENT LAB
Why does ice float on water?
Density
Density is a property of matter that is often used by chemists as an “identification tag” for a substance.
Density = Mass / Volume (D=m/V)Units for density include g/cm3, g/mL, kg/L or
kg/m3
Units : Always a mass over a volume Remember 1 mL= 1 cm3
United streaming video clip: Physical Science Series: Properties of Matter- density
http://10.163.0.75/videos/Properties%20of%20Matter/chp3168_300k.asf
You have two blocks both composed of the same type of wood. However Block A is 1000 cm3, and Block B is 1 cm3. Which block has the greater density???
Density ContinuedSubstances and their densities:Water 1 g/mLTable Sugar 1.59 g/mLGold 19.3 g/mLIce 0.917 g/mLEthanol 0.789 g/mLIf all of these substances were poured
in one container, list the order of the substances bottom to top.
Less dense objects rise. Explain how a lava lamp works. Explain helium balloons. Explain the raisins in the carbonated
beverage.
Let’s try some calculations…
CHECK YOUR UNITS.
1. What is the density of an object that has a mass of 5 g and a volume of 2.5 cm3?
Some liquid nitrogen has a mass of 14 grams and a volume of 36.3 mL. What is the density?
A substance has a mass of 24.32 kilograms and a volume of 19.8 L. What is the density?
What if you are solving for volume or mass?
Remember on the EOC you will only be given the form. D=m/v- You must know how to derive the other 2 equations
Solving for volume:
Solving for mass:
Circle method
What is the mass of an object with a density of 10 g/mL and a volume of 2 mL?
How much space does 4 g of a substance occupy if it has a density of 7.6 g / mL?
Demonstration of Density
OBJ: to see if different sodas have different densities
We will use coke and diet coke to see if the two sodas have different densities
Question: Based on what was observed, what can you conclude about the density of coke and diet coke?
The “recycling factory”
Block lab