“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