year exam revision

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