Physical Science Chapter 1 & 2

SI (International/Metric System) of Units Universally accepted way to measure things Based off of the number 10 Conversions can be done easily

Length Defined as the straight line distance between two points. The Base SI unit of measurement for length is a meter (m). How do you measure length?

Mass A measure of the amount of matter in an object. SI units of measurement are grams (g). Mass remains constant no matter where an object is in the universe. We will be measuring mass with a triple beam balance.

Volume The measure of the amount of space an object takes up. SI units Liquids are measured in Liters (L) Solids are measured in centimeters cubed (cm 3 ) Volume can be measured in a graduated cylinder.

Ladder Method

SI Prefixes kilo k thousand (10 3 ) 1,000 Hecto h hundred (10 2 ) Deca d Ten (10) deci dc tenth (10 -1 ).1 centi c hundreth (10 -2 ).01 mili m thousandth (10 -3 ).001 micro μ millionth (10 -6 ) nano n billionth (10 -9 )

Practice problems Solve the following: 2,564 kg = ______mg 326 L= _____ kL 4,789.6 g = _______mg 1, mm = _____m

Scientific Notation Definition: A way of expressing a value as the product of a number between 1 and 10 and a power of 10. For example, the number 1,000,000,000 can be written in scientific notation as 1.0 x In other words, the exponent, 9, tells you that the decimal point is 9 places to the right of the 1. What is the value of a number that has the scientific notation of 7.6 x ?

Why Scientific Notation? How far do you think the earth is from the sun? What is the mass of an electron? (Negatively charged particle that moves around an atom) Big or Small, Scientific Notation Fixes it all!

Astronomical Unit Distance from the Earth to the sun 149,597,870,700 km

Mass of an electron grams

Scientific Notation Makes it easier AU = 1.49 x meters When we multiply a positive exponent, we move the decimal point to the right, that many place values. Mass of an electron= 9.1 x When we multiply by a negative exponent, we move the decimal point to the left, that many place values.

Multiplying Scientific Notation When you multiply, you multiply the coefficients and add the exponents. When you divide scientific notation you divide the coefficients and subtract the exponents. Needs to be between 1 and 10

Multiplying (1.6 x 10 7 ) x (2.1 x 10 6 ) (2.76 x 10 8 ) x (3.6 x 10 4 ) Division (7.2 x 10 6 ) / (8.4 x 10 4 ) (5.2 x ) / (7.2 x )

Matter – Anything that has mass and takes up space. Chemistry – Study of matter All matter has physical and chemical properties: Physical Property – Observed without changing the substance’s composition. -Example – The freezing of water Chemical Property – Observed by changing the substance’s composition -Example – Burning paper into ash and carbon dioxide.

Pure Substance – Matter that has the same composition throughout. Type of Pure Substance DefinitionSmallest Unit of Matter Elements Matter that cannot be broken down into simpler substances (Example: Oxygen) Atom Compounds Matter made from two or more substances in a fixed ratio. (Example (Water – H 2 O) Cannot be separated by a physical change Molecule

Impure Substances Mixtures do not have consistent chemical compositions throughout. Components are not chemically combined. Can be separated by a physical change. Type of MixtureDefinitionExample HomogeneousMixture where parts are hard to distinguish Solution (Ex: Salt water) HeterogeneousMixture where parts are easy to distinguish Suspension (Oil and water)

Physical Properties Viscosity = A fluid’s resistance to flow Conductivity = ability to allow heat flow Malleability = ability to hammer without shattering Hardness = ability to scratch other objects Temperature – average energy of atoms/molecules of a substance. Melting Point = temperature at which a substance goes from solid to liquid Boiling Point = temperature at which a substance goes from liquid to gas Density = ratio of mass to volume

More on Density A measure of how many atoms are in a enclosed area. The closer together the atoms, the more dense the object is. Calculation to determine density is D= M/V

Density Problems An object has the mass 0f 32 g and a volume of 72 cm 3. What is the Density of this object? Will this object sink or float? An object has the mass of 162 g and has a volume of 46 cm 3. What is its density? Will this object sink or float?

Measuring Temperature Kelvin, Celsius, Fahrenheit Water boils at 212 °F, 100 °C, 373 °K Human body temperature 98.6°F, 37°C, 310°K Average room 68°F, 20°C, 293°K Water freezes 32°F, 0 °C, 273°K °C = 5/9 (°F – 32.0°) °F= 9/5 (°C) ° K = °C + 273