year exam revision
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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. - PowerPoint PPT PresentationTRANSCRIPT
Year Exam RevisionYear 9 topics – Electricity, Atoms, Body Beautiful and
Waves
ATOMS
ATOMSAn 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
AtomsProtons have a _________ charge
Neutrons have a _________ charge
Electrons have a _________ charge
There is the same number of ________ and ____________ in each atom.
AtomsProtons have a POSITIVE charge
Neutrons have NO charge
Electrons have NEGATIVE charge
There is the same number of Electrons and Protons in each atom.
ElementAre substances which contain only ONE kind of atom.
Will contain more than ONE atom.
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.
A compoundImage: http://home.clara.net/darvill/hotpots/emc.htm Info: http://www.powermasters.com/Matter/matter%20page%2002.html,
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
CompoundsWhat elements make up the following compounds?1. H2O
2. H2SO4
3. HNO3
2 Hydrogen Atoms and 1 oxygen
2 Hydrogen, 1 sulfur and 4 oxygen
1 Hydrogen, 1 Nitrogen and 3 oxygen
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
Pure element is;a) A, C and Db) Bc) GA pure compound is;a) A, C and Db) Bc) G
Mixture of two compounds is;a) Gb) Bc) F Mixture of two elements is;a) Bb) E and Fc) G
http://home.clara.net/darvill/hotpots/emc.htm
Periodic TableContains 8 Groups (or families) of elements (run
vertically)
Group 1 are known as Alkali Metals
Group 2 are known as Alkaline Earth Metals
Group 7 are known as Halogens and are brightly coloured
Group 8 are known as Noble Gases.Do not readily react with other substances
Ions Ions are atoms that either lose or gain electrons.
IsotopesAtoms of the same element can have different numbers
of neutrons; the different possible versions of each element are called isotopes.
ISOTOPESWhen 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
Radioactive IsotopesAre made artificially (man made) by bombarding their
atoms with subatomic particles like protons and neutrons.
Nuclear RadiationNuclear 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
Alpha Radiation α (particles)
Are 2 helium nucleui that contain 2 protons and 2 neutrons
They are positively charged
Can not travel easilyStopped by paper and skin
Pose little hazard
The symbol for alpha is α
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
Gamma RaysAre 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
Half-Life of isotopesThe 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.
Electricity
1. Year 9 Electricity Revision2. What is electricity?3. What 3 things does a circuit need to work?4. What is the definition of voltage?5. What unit is Voltage measured in and what is the symbol?6. What is the definition of current?7. What unit is Current measured in and what is the symbol?8. What is the difference between a material that conducts electricity, a material that
insulates electricity and a material that resists electricity?9. What unit is it measured in?10. 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?11. What is the safety of a fuse or circuit breaker in a circuit?12. Draw a series circuit.13. Draw a parallel circuit.14. Name an advantage and disadvantage of a parallel and a series circuit.15. Batteries and Cells16. Parallax error17. Negative readings on ammeter and voltmeter
Electric Circuits Cont...For an electric circuit to work, it must have 3
essential parts.1. A power supply.2. A load (or loads) in which electrical
energy is converted into other forms of energy.
3. A conducting path, which allows electricity to flow around the circuit.
Circuit SymbolsConducting wire
CellSource of current
BatterySource of current
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
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)
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
Series circuitsAll 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??
Parallel circuitSide by Side – splits into branchesIn 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??
CurrentThe flow of electrons around a circuit from
positive to negative.Is measured in Amps (A)
voltageThe measure of electrical potential energy
gained or lost by electric charge as it moves through a circuit
AMMETERCurrent is measured in Amps (A)Link your ammeter in seriesThe 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
NOZERO
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 pointsVoltage 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
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
resistanceIs a measure of how difficult it is for electrons to
flow through part of a circuit.
Ohm’s LawA law stating that electric current is
proportional to voltage and inversely proportional to resistance.
R = V IWhere:R = Resistance (Ω) I = Electric Current (Amps)V = Voltage (Volts)
V
RI
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
Dynamic Earth
What are the layers of the earth?
The CrustThe MantleOuter Core Inner Core
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.
What are mid-ocean ridges?
How are they formed?
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.
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
EVIDENCE FOR PLATE MOVEMENT
FossilsSimilarities in current and extinct organisms
found on different continents.Matching continent marginsmid-ocean ridges (where plates meet and move)
on oceans.
volcanoesA 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.
EarthquakesEarthquakes 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.
The earth’s Sphere’s Greek words
Stone – LithoAir – AtmoWater – HydroLife – 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).
Lithosphere (stone)The lithosphere is the solid, rocky crust covering
entire planetThis crust is inorganic and is composed of
minerals. It covers the entire surface to the earth from the top of Mt Everest to the bottom of the Mariana Trench.
Hydrosphere (water)The hydroshpere is composed of all the water on
or near the earth. This includes the oceans, rivers, lakes and even the moisture in the air.97% of the earth’s water is in the ocean. The remaining 3% is fresh water.
Biosphere (life)The biosphere is composed of all living
organisms. Plants, animals and one-celled organisms are all part of the biosphere.
Atmosphere (Air)The atmosphere is the body of air which
surrounds our planet. Most of our atmosphere is located close to the earth’s surface where it is most dense. The air of our planet is 79% nitrogen and 21% is oxygen. The rest is composed of carbon dioxide and other gases.
Body Beautiful
Microbes Keywords1. Microorganisms= Microscopic living organism.
They are tiny living things, so small we need a microscope to see them.
2. Microbes= Also called microorganisms.3. Bacteria=A microorganism that is very small,
which consists of only one cell4. Viruses=Microbes that are smaller than bacteria5. Fungi=Are small and round, examples include
yeasts and moulds
Fighting infection• If microbes penetrate the body’s barriers the
immune system is used to clear up infection• White blood cells found in blood fight against
microbes. They destroy microbes in 3 ways:
1. They swallow up microbes2. Produce antibodies that attach to microbes3. Destroy toxins made by microbes
Infectious Diseases Those diseases that could be spread or transferred from one organism (living thing) to another
Can you think of any disease that you can transfer in the environment?
Infectious diseasescaused by pathogens (such as bacteria, viruses, fungi,
protozoans, prions or parasites), They invade the body and stop it from working properly
transmitted from one person to another, by sneezing, coughing, sexual activity, blood, poor hygiene, through wounds, etc.
Some of these can be very contagious (eg. Cold) while others are generally non-contagious (eg. Food poisoning)
Non- Infectious Diseases
Cannot be spread from one person to another
Can you think of any disease that you cannot
transfer?
Non-infectious DiseasesNon-infectious diseases are a different class of
diseases that are not caused by pathogens/microbes
They are not contagious at all – so they can’t be caught from another person.
They are caused by other factors.
Non-infectious diseasesThere are several kinds of non-infectious
diseases:
1. Genetic Diseases
2. Environmental diseases
3. Nutritional Diseases
4. Cancers
5. Auto-immune diseases
The Reproductive System
What is ovulation?
The Reproductive System
Overview Spinal Cord
Brain
Peripheral Nerves
http://www.abcbodybuilding.com/anatomy/introductiontonevroussystem.htmDiagram from:
Central Nervous System
The endocrine system consists of glands and
the chemicals they produce, called
hormones
Function of the Nervous System
The bodies control center
Collects information from internal/external stimuli
Analyzes the information collected
Initiates appropriate responses
The endocrine system is a way of coordinating
things that happen in the body eg the timing of
puberty.
Hormones travel from the gland that releases them through the blood stream to the target cells much
more slowly than electrical messages travel through nerves (nervous system .
What technological advancement have been made in science over the last 100years to increase our knowledge in science?
WAVES
ReflectionWhen light bounces off the surface of a
substance, allowing you to see a non-luminous (doesn't’t give off light) object.
The Law of ReflectionLight is known to behave in a very
predictable mannerThe law of reflection states that when
a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.
Ray of Incidence
Ray of Reflection
Kevin Quigley. 2006.
RefractionAs light travels through a transparent
or translucent it can slow down or speed up. As light changes speed it
will BEND or change direction.
This BENDING of light can produce optical illusions as the brain always thinks light is traveling in straight
lines.
Kevin Quigley. 2006.
The Law of Refractionnormal
Air (less dense)
Glass (more dense)
Air (less dense)
WavesIs the transfer of energyIt is a pressure disturbance on particles . As
each particle become disturbed it exerts its force on to the next particle
There are 2 different types of Waves:Light waves - Transverse AndSounds waves - Compression
Transverse Waves - LightThe vibrations are at right angles to the direction of
travel of the wave
Travel very fast - 300,000 kilometers per second
e.g. water waves, light waves
Compression Waves - Sound aka: longitudinal waves
The particles in the medium vibrate back and forth parallel to the direction in which the wave is travelling
Travels at 331 m/s (slower than light)
e.g. a ruler on a desk
3 ways to describe a wave
Wavelength; this is the distance from the crest of one wave to the crest of the next.
Frequency; this is the number of waves that pass a point in each second. (pitch)
Amplitude; this is the measure of the amount of energy in a sound wave. (Loud/Soft)
Electromagnetic SpectrumThe electromagnetic spectrum is the range of
all possible frequencies of electromagnetic radiation.
EM Spectrum
Saving the PlanetReview:Ozone layer – how it is being created? How to
look after it?Global WarmingPollutionFossil fuelsWater cycle, Carbon cycle and nitrogen cycle