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Year Exam Revision

Year Exam Revision. Year 9 topics – Electricity, Atoms, Body B eautiful and Waves. ATOMS. ATOMS. An ATOM is made of; A Nucleus (center) with one or more Electrons spinning around it. The Electron has a negative charge.

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Year Exam Revision

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  1. Year Exam Revision Year 9 topics – Electricity, Atoms, Body Beautiful and Waves

  2. ATOMS

  3. ATOMS An ATOM is made of; A Nucleus (center) with one or more Electrons spinning around it. The Electron has a negative charge. The nucleus of the atom has a Proton with a positive charge and a Neutron that has no electrical charge. The number of Electrons, Neutrons and Protons that an atom has determinesits properties and weight. http://www.powermasters.com/Matter/matter%20page%2002.html

  4. Atoms Protons have a _________ charge Neutrons have a _________ charge Electrons have a _________ charge There is the same number of ________ and ____________ in each atom.

  5. Atoms Protons have a POSITIVE charge Neutrons have NO charge Electrons have NEGATIVE charge There is the same number of Electrons and Protons in each atom.

  6. Element • Are substances which contain only ONEkind of atom. • Will contain more than ONE atom.

  7. WHAT IS A COMPOUND? • A substance formed from two or more elements • For example, water is a compound composed of two hydrogen atoms for every oxygen atom. Image: http://home.clara.net/darvill/hotpots/emc.htm Info: http://www.powermasters.com/Matter/matter%20page%2002.html, A compound

  8. The glass of water above is a COMPOUND. It’s made up of millions of MOLECULES of water. http://www.powermasters.com/mini_lessons.html

  9. Compounds What elements make up the following compounds? • H2O • H2SO4 • HNO3 2 Hydrogen Atoms and 1 oxygen 2 Hydrogen, 1 sulfur and 4 oxygen 1 Hydrogen, 1 Nitrogen and 3 oxygen

  10. WHAT IS A MIXTURE? • two or more substances mixed together in such a way that each remains unchanged (sand and sugar form a mixture). • NOT chemically bonded A Mixture of 2 compounds Image: http://home.clara.net/darvill/hotpots/emc.htm, Info: Google Definition Search

  11. Pure elementis; a) A, C and D b) B c) G A pure compound is; a) A, C and D b) B c) G Mixture of two compounds is; a) G b) B c) F Mixture of two elements is; a) B b) E and F c) G http://home.clara.net/darvill/hotpots/emc.htm

  12. Periodic Table • Contains 8 Groups(or families) of elements (run vertically) • Group 1 are known as • AlkaliMetals • Group 2 are known as • Alkaline Earth Metals • Group 7 are known as Halogensand are brightly coloured • Group 8 are known as Noble Gases. • Do not readily react with other substances

  13. Ions • Ions are atoms that either lose or gain electrons.

  14. Isotopes • Atoms of the same element can have different numbers of neutrons; the different possible versions of each element are called isotopes.

  15. ISOTOPES • When protons and neutrons in the nucleus are held very tightly in the nucleus, the atom is said to be STABLE • However, in some atoms the protons and neutrons in the nucleus are NOT held very strongly in the nucleus, the atom is said to be UNSTABLE

  16. Radioactive Isotopes • Are made artificially (man made) by bombarding their atoms with subatomic particles like protons and neutrons.

  17. Nuclear Radiation • Nuclear radiation is energy emitted by radioactive substances from the nucleus. • Rutherford found there are 3 types of nuclear radiation: • Alpha Radiation (particles) • Beta Radiation (particles) • Gamma Rays

  18. Alpha Radiation α (particles) • Are 2 helium nucleui that contain 2 protons and 2 neutrons • They are positively charged • Can not travel easily • Stopped by paper and skin • Pose little hazard • The symbol for alpha is α

  19. Beta Radiation β (particles) • They are the same size and mass as electrons • Can have a positive or negative charge • Can travel up to the speed of light (very fast) • Can be very harmful • Can penetrate human skin and damage living tissue, but cant penetrate plastic, wood or aluminum • The symbol for beta is β

  20. Gamma Rays • Are not particles, bursts of energy released after Alpha or Beta particles are emitted • Travel at the speed of light • Are highly penetrating • Can cause serious and permanent damage to living tissue • Can only be stopped by lead or concrete • The symbol given to Gamma Rays is ϒ

  21. Half-Life of isotopes • The nuclei of different radioactive substances decay at different rates. Some in a few seconds and some over thousands of years. • The time taken for half of all the nuclei in a simple sample of a radioisotope to disintegrate or decay is known as the half-life.

  22. Electricity

  23. Year 9 Electricity Revision • What is electricity? • What 3 things does a circuit need to work? • What is the definition of voltage? • What unit is Voltage measured in and what is the symbol? • What is the definition of current? • What unit is Current measured in and what is the symbol? • What is the difference between a material that conducts electricity, a material that insulates electricity and a material that resists electricity? • What unit is it measured in? • What is the formula for Ohm’s Law? What is the resistance of a circuit that has a current of 0.2 amps and a voltage of 40 volts? • What is the safety of a fuse or circuit breaker in a circuit? • Draw a series circuit. • Draw a parallel circuit. • Name an advantage and disadvantage of a parallel and a series circuit. • Batteries and Cells • Parallax error • Negative readings on ammeter and voltmeter

  24. Electric Circuits Cont... • For an electric circuit to work, it must have 3 essential parts. • A power supply. • A load (or loads) in which electrical energy is converted into other forms of energy. • A conducting path, which allows electricity to flow around the circuit.

  25. Circuit Symbols • Conducting wire • Cell • Source of current • Battery • Source of current

  26. Circuit Symbols (Cont’d) • Switch • Stop or start electron flow • Fuse • Prevents too much current from flowing • Made of thinner wire than the rest of the circuit and melts if the circuit gets too hot

  27. Circuit Symbols (Cont’d) • Ammeter • measures how fast the electrons are moving (measured in amperes) • Voltmeter • measures how much energy the flowing electrons have (measured in volts)

  28. Circuit Symbols (Cont’d) • Lamp • Converts electricity into light and heat • Resistor • Resists the flow of electrons through the wire • Signifies a load • Converts electrical energy

  29. Series circuits All in a row – one single loop • In a series circuit, the same current flows through the load. • In a circuit with 3 light bulbs, only one-third of the electrical energy available from the power supply is transformed in each of the load. • What happens to the brightness of the light in the light bulbs??

  30. Parallel circuit Side by Side – splits into branches • In a parallel circuit, the current is divided evenly through the load • In a circuit with 3 light bulbs, the electrical charge flowing through each light bulb is equal. • Each globe uses the full voltage of the power supply • What happens to the brightness of the light in the light bulbs??

  31. Current • The flow of electrons around a circuit from positive to negative. • Is measured in Amps (A)

  32. voltage • The measure of electrical potential energy gained or lost by electric charge as it moves through a circuit

  33. AMMETER • Current is measured in Amps (A) • Link your ammeter in series • The ammeter measures the size of electric current flowing in the circuit from POSITIVE to NEGATIVE • If the switch is OPEN there is Electric current flowing, so reading on the ammeter • If the switch is CLOSED, the circuit is connected and a current is flowing NO ZERO

  34. VOLTMETER • Is measured in volts (V) • Connect your voltmeter in parallel • It is used to measure voltage – a loss or gain of volts between 2 different points • Voltage is measuring the difference of volts between 2 point, so if the voltage is the same it will show a reading of . • So if you get a reading of zero, does this mean there is no volts flowing between the 2 points? NOTE* from the negative side of the load to the power supply, the voltage is zero as the power supply sucks up all the electrons. ZERO

  35. Voltage vs current Current can not flow without voltage Voltage Measured in Volts Measured by a voltmeter (connected in parallel) Flow of electrons Current Measured in Amps Measure by a ammeter (connected in series) Pressure/force of Electrons

  36. resistance • Is a measure of how difficult it is for electrons to flow through part of a circuit.

  37. Ohm’s Law • A law stating that electric current is proportional to voltage and inversely proportional to resistance. R = V I Where: R = Resistance (Ω) I = Electric Current (Amps) V = Voltage (Volts) V R I

  38. Example • The electric current of the light below is 0.4A and the voltage drop is 2 volts. Work out the resistance R = V = 2 I 0.4 Resistance = 5 ohm’s

  39. Dynamic Earth

  40. What are the layers of the earth? • The Crust • The Mantle • Outer Core • Inner Core

  41. Theory of Plate tectonics • A theory to explain how continents have moved apart. • The crust in broken into many pieces, some small and some large. These pieces are called ‘plates’ • These plates are moving in different directions • Moving together • Moving away • Sliding past each other. The movement of the plates cause a movement of the continents.

  42. What are mid-ocean ridges? • How are they formed?

  43. The main features of plate tectonics are: 1. The Earth's surface is covered by a series of crustal plates. 2. The ocean floors are continually, moving, spreading from the center, sinking at the edges, and being regenerated. 3. Convection currents beneath the plates move the crustal plates in different directions. 4. The source of heat driving the convection currents is radioactivity deep in the Earths mantle.

  44. Define the following terms • Convergent • Divergent • Subduction • Faults • Folds Use Scootle to help you; log on to scootle learning and enter the following student PIN access: HKARCK

  45. EVIDENCE FOR PLATE MOVEMENT • Fossils • Similarities in current and extinct organisms found on different continents. • Matching continent margins • mid-ocean ridges (where plates meet and move) on oceans.

  46. volcanoes • A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. (divergent plate boundaries) • Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. • Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods.

  47. Earthquakes • Earthquakes are the shaking, rolling or sudden shock of the earth’s surface. • They are the Earth's natural means of releasing stress. • When the plates squeeze or stretch, huge rocks form at their edges and the rocks shift with great force, causing an earthquake. (transformation) • More than a million earthquakes rattle the world each year.

  48. The earth’s Sphere’s • Greek words • Stone – Litho • Air – Atmo • Water – Hydro • Life – Bio All 4 spheres can be and often found in a single location. Eg. Soil will have mineral material (lithosphere) there will be moisture (hydrosphere), living insects and plants (biosphere) and pockets of air between soil pieces (atmosphere).

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