Strand A – The Nature of Matter • What is matter? • Anything that has mass and takes up space. • Density – the amount of matter in a given volume (D=M/V) • Ductility – the ability to be pulled into a thin strand, like a wire • Malleability – the ability to be pressed or pounded into a thin sheet
Formula for Density • D = M/V • Where • D=Density • M=Mass • V=Volume
Strand A – The Nature of Matter • Electrical Conductivity – How well a substance allows electricity to flow through it • Solubility – The ability to dissolve in another substance
Strand A – The Nature of Matter • Physical Properties • Are those that can be observed without changing the make-up, or identity of the matter. • Chemical Properties • Describe matter based on its ability to change into a new kind of matter. Ie, paper/flammability, iron/O2
Strand A – The Nature of Matter • Physical Change – occurs when a physical property (size/shape) of a substance is changed; many physical changes can be undone. Ie, folding paper • Chemical Change – occurs when a one or more substances are changed into new substances with different properties; cannot be undone by physical means
Strand A – The Nature of Matter • Defining Features • Solid • Keeps it shape and volume • Liquid • Takes the shape of its container • Keeps the same volume, in a container or not • Can flow • Gas • Takes the shape of its? • Takes the volume of ? • Can ?
Strand A – The Nature of Matter • Boiling Point – temperature at which a substance changes from a liquid state to a gaseous state • Freezing Point – temperature at which a substance changes from a liquid state to a solid state • Melting Point – temperature at which a substance changes from a solid state to a liquid state • Condensation Point – temperature at which a substance changes from a gaseous state to a liquid state • Sublimation – change from the solid state to the gaseous state • Deposition – change from the gaseous state to the solid state
Strand A – The Nature of Matter • Temperature – measure of the average kinetic energy of the particles of a substance. Scales used?
Strand A – The Nature of Matter • Waves • Crest – peak/highest point of wave • Trough – valley/lowest point of wave • Amplitude – distance the wave oscillates from its resting position. The larger the amplitude, the more energy carried by the wave. • Wavelength – the distance from one point on one wave to a corresponding point on an adjacent wave, ie. crest to crest, rp to rp, trough to trough • Resting Position
Strand A – The Nature of Matter • Element – simplest form of matter • Atom – smallest particle into which an element can be divided and still have properties of that element. • Compound/Molecule – Two or more elements that are combined. • Mixture – a combination of two or more substances that have not combined chemically
Strand A – The Nature of Matter • Subatomic Particles • Proton – positive charge – nucleus • Neutron – no charge – nucleus • Electron – negative charge – outside the nucleus (electron clouds) • Proton and neutrons have about the same mass. Electrons are significantly smaller. • An atom is identified by the number of protons in its nucleus
Strand A – The Nature of Matter • Isotopes – Isotopes are atoms of the same element that have a different number of neutrons. • Hydrogen has one proton. • 0 neutron – protium • 1 neutron – deuterium • 2 neutrons – tritium
A. Mixture B. Solution C. Compound D. Pure Substance
You are correct! Why are B, C and D not correct?
Strand B - Energy • Energy – the ability to do work • Geothermal – energy obtained from the thermal energy inside Earth • Mechanical – energy an object has because of its motion or position (kinetic/potential) • Nuclear – energy contained in the nuclei of atoms
Strand B - Energy • Wind – using the wind (turbines) • Hydroelectric – using water • Tidal – using the waves/tides • Solar – using sun (photovoltaic cells) • Fossil fuels – oil, coal, natural gas (formed millions of years ago). • Electrical – energy produced by electric charges
Turbines, turbines, turbines!!!! • Remember that most power plants have a turbine somewhere in them that allows them to convert (not create) energy. • Remember that energy can never be created or destroyed.
Strand B - Energy • Sound – energy carried by sound waves • Light – energy carried by light and other kinds of electromagnetic waves • Chemical – energy stored in chemical bonds • Thermal – Energy related to the temperature of a substance • Conduction, Convection, Radiation
Strand B - Energy • Conduction – transfer of heat from a warmer substance to a cooler substance (contact) • Convection – transfer of heat warmer fluid/gas rises and cooler sinks • Radiation – transfer of heat in the form of electromagnetic waves at random
Conduction Convection Radiation
Strand B – Energy • Law of Conservation of Energy – Energy cannot be created nor destroyed, it can only change form or be transferred • Kinetic Energy – energy an object has in motion • Potential Energy – stored energy an object has
Strand B - Energy • Energy from Sun (electromagnetic spectrum) • Energy inefficiency (heat loss) ie, lamp example • Heat flow warmer to cooler • Energy flow – sun plants animals fossil fuels heat
Benchmarks: SC.B.1.2.2, SC.B.1.2.3, SC.B.1.2.4, SC.B.1.2.5 and SC.B.1.2.6 F. Electrical G. Heat H. Light I. Mechanical
You are correct! Why are G, H and I not correct?
Strand C – Force and Motion • Force – push or pull
Scalars & Vectors • The motion of objects can be described by words - words such as distance, displacement, speed, velocity, and acceleration. These mathematical quantities which are used to describe the motion of objects can be divided into two categories. The quantity is either a scalar or a vector. These two categories can be distinguished from one another by their distinct definitions: • Scalars are quantities which are fully described by a magnitude alone. • Vectors are quantities which are fully described by both a magnitude and a direction.
Scalars & Vectors • Distance and speed are scalar quantities • Displacement and velocity are vector quantities. • Examples: While speed (like 30km/hr) is a scalar, velocity (30km/hr North) is a vector, consisting of a speed and a direction (north).
Scalar or Vector? • 5 m • 30 m/sec, East • 20 degrees Celsius • 256 bytes • 4,000 calories • 5 mi., right
Distance/Displacement • Distance and displacement are two quantities which may seem to mean the same thing, yet they have distinctly different meanings and definitions. • Distance is a scalar quantity which refers to "how much ground an object has covered" during its motion. • Displacement is a vector quantity which refers to "how far out of place an object is"; it is the object's change in position.
Distance/Displacement Check • A student walks 4 meters East, 2 meters South, 4 meters West, and finally 2 meters North. 4 meters 2 meters 2 meters 4 meters
Distance/Displacement • Even though the student has walked a total distance of 12 meters, her displacement is 0 meters. During the course of her motion, she has "covered 12 meters of ground" (distance = 12 m). Yet, when she is finished walking, she is not "out of place" – i.e., there is no displacement for her motion (displacement = 0 m). Displacement, being a vector quantity, must give attention to direction. The 4 meters east is canceled by the 4 meters west; and the 2 meters south is canceled by the 2 meters north.
Distance/Displacement Check • The diagram below shows the position of a cross-country skier at various times. At each of the indicated times, the skier turns around and reverses the direction of travel. In other words, the skier moves from A to B to C to D. Use the diagram to determine the distance traveled by the skier and the resulting displacement during these three minutes. A B 40 m 40 m___ ‘ 100 m ‘ C D
Distance/Displacement • Seymour Action views soccer games from under the bleachers. He frequently paces back and forth to get the best view. The following diagram below shows several of Seymour's positions at various times. At each marked position, Seymour makes a "U-turn" and moves in the opposite direction. In other words, Seymour moves from position A to B to C to D. What is Seymour's resulting displacement and distance of travel?
Distance/Displacement D B C A ___________________________________ -10 0 10 20 30
Let’s Check • What is the displacement of a cross country team that begins a ten mile course ending up back at the school? • What is the distance and displacement of the race car drivers in the Indy 500?
Speed • Speed is a scalar quantity which refers to "how fast an object is moving." A fast-moving object has a high speed while a slow-moving object has a low speed. An object with no movement at all has a zero speed.
Constant Speed • Moving objects don't always travel with erratic and changing speeds. Occasionally, an object will move at a steady rate with a constant speed. That is, the object will cover the same distance every regular interval of time. For instance, a cross-country runner might be running with a constant speed of 6 m/s in a straight line. If her speed is constant, then the distance traveled every second is the same. The runner would cover a distance of 6 meters every second. If you measured her position each second, you would notice that her position was changing by 6 meters each second. The following data tables depict both constant and changing speeds: