J.C Physics

Created by the class of….

• 3Br & 3Da

• CBS Kilkenny 2012

UUse simple materials to se simple materials to generate static electrictygenerate static electricty

STATIC ELECTRICTYSTATIC ELECTRICTY

Build up of charge

MethodMethod

1.Rub a plastic biro against the sleeve of 1.Rub a plastic biro against the sleeve of your jumperyour jumper

2.The biro will pick up small pieces of 2.The biro will pick up small pieces of paperpaper

ConclusionConclusion

This happens because the pen becomes This happens because the pen becomes negatively charged. negatively charged.

Also see page 362 in textbook

Conversion of Conversion of Electrical Energy to Electrical Energy to Magnetic to Kinetic Magnetic to Kinetic

EnergyEnergy

See page 319 in textbook

MethodMethod

MethodMethod

Connect 6 V battery to nailConnect 6 V battery to nail Wrap wire around nailWrap wire around nail Turn on batteryTurn on battery Put nail near paper clipsPut nail near paper clips

Results Results

The nail was magnetised. It picked The nail was magnetised. It picked up the paper clipsup the paper clips

A conductor is a material through which an electrical charge can flow.

An insulator is a material through which an electrical charge cannot flow.

Perspex rod wire

To see if a piece of wire conducts To see if a piece of wire conducts electricityelectricity

Set up the circuit.Set up the circuit. Connect the wire to the circuit as shown Connect the wire to the circuit as shown

on in the diagram.on in the diagram. An additional wire is inserted here

Result – the light bulb will light up showing that wire is a conductor of electricity

To see if a Perspex rod conducts To see if a Perspex rod conducts electricityelectricity

Set up the circuit as before.Set up the circuit as before. Replace the wire with a Perspex rod.Replace the wire with a Perspex rod.

Insert a Perspex rod here instead of the wire

Result – the light bulb will not light up showing that the Perspex rod is not a conductor of electricity

To Plot the Magnetic Field of a To Plot the Magnetic Field of a Bar MagnetBar Magnet

Equipment:Equipment:1 Bar1 Bar magnet,2 magnet,2 Science books ,a Sheet ofScience books ,a Sheet of plain plain paper, iron filings .paper, iron filings .

Step Step 1:1:Wedge the Bar magnet Wedge the Bar magnet between thebetween the the two books. the two books. Step Step 2:2:Place the sheet of paper Place the sheet of paper overover the two books .the two books .

Step 3 Step 3 ;;Sprinkle the iron filings over Sprinkle the iron filings over the sheet and watch for resultthe sheet and watch for result

Result Result ; A picture of the magnetic ; A picture of the magnetic poles should be visibly clearpoles should be visibly clear

PODPOD

Series & Parallel Circuit

What it is…

•Bulbs are arranged one after another.

•If you remove 1 bulb the other won’t work.

•The current in the battery divides.

•Some current passes through one bulb and the rest through the second.

•If the bulbs are identical the current equally divides.

Examples

Headlights in a car are parallel.Christmas lights are both series

and parallel.If you remove one bulb and it all

goes off then it is a series circuit.If not then it is a parallel cricuit.

Calculating

V = voltageI = currentR = resistor

Amps measured with Amps measured with Ammeter Ammeter

1.1. Connect the Battery and the Connect the Battery and the Ammeter together Ammeter together

2.2. Attach a lamp onto the circuit Attach a lamp onto the circuit 3.3. Observe Observe

Measuring Voltage with a voltage Measuring Voltage with a voltage meter meter

1.Connect the voltage meter , battery and 1.Connect the voltage meter , battery and bulb into a circuit bulb into a circuit

2. Observe the results on the voltage meter 2. Observe the results on the voltage meter

ResistanceResistance

Measured using an ohmmeter.Measured using an ohmmeter. Units= ohmsUnits= ohms

DIRECT CURRENT (D.C)

• A current that flows in one direction only.

Alternating current (A.C)

• A current that is continually changing in direction

Domestic Voltage supply

• 240 volts

The chemical effect of an electric current•Is the charging of a phone

•The magnetic effect of an electric current•Is the speaker of a stereo

•The heating effect of an electric current •Is the shower

What happens a LDRs What happens a LDRs resistance measure under resistance measure under

varying degrees of light varying degrees of light brightnessbrightness

1.If bright light falls on a LDR the 1.If bright light falls on a LDR the resistance is low . A larger current can flow resistance is low . A larger current can flow through the resistor .through the resistor .

2.If dim light falls on a LDR the resistance 2.If dim light falls on a LDR the resistance is high . A smaller current will now flow is high . A smaller current will now flow through the resistor .through the resistor .

3.Using a LDR you can arrange for an 3.Using a LDR you can arrange for an electrical appliance to be controlled by electrical appliance to be controlled by light . In fact,some appliances can be light . In fact,some appliances can be switched on or switched or switched off by switched on or switched or switched off by simply shining light on the LDR connected simply shining light on the LDR connected to them .to them .

Unit of electrical energy = Unit of electrical energy = kilo watt-hour {kWh}kilo watt-hour {kWh}

Name 3 wires in a plug = Name 3 wires in a plug = earth/live/neutralearth/live/neutral

WORK,POWER AND WORK,POWER AND ENERGYENERGY

Work= force x distanceWork= force x distanceForce= Newtons (N)Force= Newtons (N)

Distance= Metres (m)Distance= Metres (m)Work=joules (J)Work=joules (J)

Advantages Advantages + + DisadvantagesDisadvantages

Non-renewable sources of energy are sources Non-renewable sources of energy are sources that will eventually run out another name for that will eventually run out another name for them is fossil fuels e.g. Oil + gas etc. them is fossil fuels e.g. Oil + gas etc.

Advantages;Advantages; Easy to get. Easy to get. Reasonably cheap. Reasonably cheap.

Disadvantages; Disadvantages; Causing greenhouse gas emissions. Causing greenhouse gas emissions. Polluting the atmosphere e.g. Acid Rain.Polluting the atmosphere e.g. Acid Rain.

Because fossil fuels are finite , we try to Because fossil fuels are finite , we try to improve our efficiency of the improve our efficiency of the renewable sources of energy. renewable sources of energy.

Examples; Examples; Solar Energy Solar Energy Hydro Electricity Hydro Electricity Wind Energy Wind Energy Nuclear Energy Nuclear Energy

Solar energy is taken straight from the rays of the Solar energy is taken straight from the rays of the sun. We convert solar energy to electrical energy sun. We convert solar energy to electrical energy using Solar Cells. We also convert energy to heat using Solar Cells. We also convert energy to heat energy using solar panels. energy using solar panels.

Advantages; Advantages; Solar energy is free.Solar energy is free. Solar energy does not cause pollution. Solar energy does not cause pollution. Disadvantages; Disadvantages; The efficiency of solar cells needs to be improved The efficiency of solar cells needs to be improved

as only a small percentage of energy is converted as only a small percentage of energy is converted to electrical energy.to electrical energy.

Solar cells are expensive to make. Solar cells are expensive to make.

By building a dam in a large river it is possible to build a vast By building a dam in a large river it is possible to build a vast amount of water. This water has potential energy when amount of water. This water has potential energy when stored behind the dam wall. When the water is released it stored behind the dam wall. When the water is released it becomes kinetic, this kinetic energy is changed into becomes kinetic, this kinetic energy is changed into electrical energyelectrical energy

Advantages;Advantages; Does not cause pollution.Does not cause pollution. cost efficient way to produce energy.cost efficient way to produce energy.

Disadvantages;Disadvantages;Flooding can destroy plant + animal habitats.Flooding can destroy plant + animal habitats. Building dams can cause flooding in valleys inhabited Building dams can cause flooding in valleys inhabited

by people.by people.

On a windy day, the moving air has a large On a windy day, the moving air has a large amount of kinetic energy. The idea is to change amount of kinetic energy. The idea is to change this kinetic energy to electrical energy. this kinetic energy to electrical energy.

Advantages; Advantages; Does not cause pollution.Does not cause pollution. Wind energy is free. Wind energy is free.

Disadvantages;Disadvantages;No electricity produced on a clam day. No electricity produced on a clam day. Large propeller masts are noisy and spoil the Large propeller masts are noisy and spoil the

natural beauty of the countryside.natural beauty of the countryside.

Nuclear energy is usually considered as renewable Nuclear energy is usually considered as renewable energy. One form, nuclear fission, uses materials like energy. One form, nuclear fission, uses materials like Uranium. Uranium is finite. Uranium. Uranium is finite.

However another fusion is used with the basic material , However another fusion is used with the basic material , water. However the technology for generating water. However the technology for generating electricity from nuclear power is not yet available. electricity from nuclear power is not yet available.

Advantages;Advantages; Nuclear fusion would use a fuel in plentiful supply.Nuclear fusion would use a fuel in plentiful supply. Nuclear energy would reduce the greenhouse Nuclear energy would reduce the greenhouse

emissions. emissions. Disadvantages;Disadvantages; Danger of a nuclear explosion. Danger of a nuclear explosion. Harmful effects of radioactive waste.Harmful effects of radioactive waste.

Tidal and Wave Energy; Tidal and Wave Energy; The kinetic energy of the waves and the tide is The kinetic energy of the waves and the tide is

converted to electrical energy. converted to electrical energy. Geothermal Energy; Geothermal Energy; Heat energy can be trapped beneath the surface Heat energy can be trapped beneath the surface

of the Earth. This heat can also be used to of the Earth. This heat can also be used to heat homes or converted to electrical energy.heat homes or converted to electrical energy.

Biomass Energy; Biomass Energy; Some plants grow very quickly e.g. Sugar Cane. Some plants grow very quickly e.g. Sugar Cane.

The oil from the plants is converted to alcohol The oil from the plants is converted to alcohol and in cars instead of petrol.and in cars instead of petrol.

SOURCES OF ENERGY PAGE 316 IN YOUR TEXT BOOK BY pierce cody

Non-Renewable Sources of Energy

Non-renewable sources of energy are sources that will eventually run out. These sources are called fossil fuels for example 1.OIL 2.COAL3.GAS4.TURF

Advantages and Disadvantages of non-renewable

Advantages 1. Easy to get 2. Reasonably cheap Disadvantages 1. Causing greenhouse gas emissions

2. Polluting the atmosphere

Renewable sources of energy • Fossil fuels will eventually run out.

Because of this we try to improve the efficiency of the renewable sources of energy. Examples pf renewable sources of energy include:

• solar energy • hydro-electricity • wind energy • nuclear energy

Example of renewable energy = SOLAR ENERGY

Advantages 1. Solar energy is free 2. Solar energy does not cause pollution Disadvantages1. The efficiency of solar cells needs to be

improved 2. Solar cells are expensive to make

Converting Light energy to Electrical energy to Kinetic

energy

By Declan Wall

Connect the solar cells to the solar motor Shine light from the lamp onto the solar

cells See page 320 in text book

Conclusion The light energy from the lamp was

converted to electrical in the solar cells which was converted to kinetic energy in the moving fan

Levers are designed to lift objects with less effort than you would have on your own.

Modern day uses for levers are in some cranes and heavy machinery.

The effort is where the lever gets its input.For example, on a tweezers, the part you push down on is the effort.

The load is the item being moved by the lever.

For example, a tractors loader lifting a bale, the bale is the load.

The fulcrum is the point where the lever pivots.

For example, the wheel on a wheelbarrow is the fulcrum.

Why do objects float on water?Why do objects float on water?Objects float on water because Objects float on water because

the object is less dense than the the object is less dense than the liquid.liquid.

What is meant by force?What is meant by force?Force causes a stationary objectForce causes a stationary object

to move.to move.What is the unit of force?What is the unit of force?

The unit of force is newton and The unit of force is newton and the symbol is N.the symbol is N.

PRESSUREPRESSURE

What is PressureWhat is Pressure

• Pressure is force per unit area• Pressure = Force divided by Area• The pressure due to a force depends on two

things Pressure increases when the force increase Pressure increases when the area that the force

is acting on decreases

• Pressure is measured in newtons per metre squared.

PressurePressure

Mathematical ExampleA stone block of weight 225000N is to be used as

a base for a sculpture. The block has dimensions

3m x 2m x 1.5m.

(i) What is the greatest possible pressure that the

block could exert on the ground

(ii) What is the least possible pressure that the

block could exert on the ground

Pressure in LiquidsPressure in Liquids

• Why do divers need to wear protective suits when diving?

• It is because the weight of the water above them exerts a great pressure. The diving suits stops the diver being squashed.

• If a diver comes up too quickly the change in pressure can be very dangerous. Bubbles of nitrogen form in the blood. This is a condition known as the bends

Atmospheric PressureAtmospheric Pressure

• Air is made up of particles of various gases. These are attracted to the earth by gravity thus they have a weight.

• The pressure due to the weight of air pressing down on the earth is called atmospheric pressure.

• This pressure acts on our bodies but luckily the pressure inside our body exerts an equal pressure outwards to balance this.

Atmospheric PressureAtmospheric Pressure

• As we increase our height above sea level the atmospheric pressure decreases.

• Our ears ‘popping’ is our body’s way of equalising the pressure on either side of our ear drum.

• In space there is no atmospheric pressure so the pressure from inside our body would have no outside pressure to balance in. This means astronauts might explode without special suits!!

Measuring PressureMeasuring Pressure

• A barometer is an instrument used to measure atmospheric pressure.

• There are two types of barometer:

(i) Mercury

(ii) Aneroid

Normal atmospheric pressure is written as

76cm of mercury

Atmospheric Pressure and WeatherAtmospheric Pressure and Weather

• The atmosphere is like a blanket around the earth. It is like a ‘sun block’ for the earth.

• Atmospheric pressure changes with the weather.

• Isobars joins places of equal pressure. If the isobars are close together winds will be strong. If far apart winds will be light

Atmospheric Pressure and WeatherAtmospheric Pressure and Weather

• If the pressure over a particular area is high it will mean fine weather.

• Low pressure areas will generally be windy and wet.

Using PressureUsing Pressure

• Hydraulics – As pressure is passed through a liquid it does not change

Atmospheric PressureAtmospheric Pressurevaries with heightvaries with height

• The atmosphere is a fluid.The atmosphere is a fluid.• Therefore the pressure in the Therefore the pressure in the

atmosphere is affected by atmosphere is affected by depth.depth.

• Depth and height are Depth and height are opposite – the greater the opposite – the greater the depth the lower the height.depth the lower the height.• Pressure increases with Pressure increases with

depth so therefore the lower depth so therefore the lower the height the greater the the height the greater the

pressure.pressure.• Atmospheric pressure on top Atmospheric pressure on top of  Mt Everest is much lower of  Mt Everest is much lower

than at sea level – about 50% than at sea level – about 50% lower.lower.

• The atmospheric pressure at The atmospheric pressure at the bottom of the deepest the bottom of the deepest mine is greater than at sea mine is greater than at sea

level. level.

High PressureHigh Pressure

Atmospheric pressure affects the weather.

High Pressure causes:• Calm, clear sunny dry

days and calm clear dry starry nights.

• Hot days and cool nights in summer.

• Cold frost nights in winter.

Low PressureLow Pressure

Low Pressure causes:• Windy, cloudy, very

humid and wet days• and nights.• Cool days and nights

in summer.• Mild days and nights in

winter.

Why do objects float on water?Why do objects float on water?Objects float on water because Objects float on water because

the object is less dense than the the object is less dense than the liquid.liquid.

What is meant by force?What is meant by force?Force causes a stationary objectForce causes a stationary object

to move.to move.What is the unit of force?What is the unit of force?

The unit of force is newton and The unit of force is newton and the symbol is N.the symbol is N.

FRICTION :There is friction between the brake pad and the wheel of the bike. This is what stops the bike :There is friction between a moving car and the air. This friction is overcome by the force of the engine

LUBRICATION :This is used to reduce the friction between two surfaces in contact e.g. bones at the joint are surrounded by a fluid that acts as a lubricant

HOOKE’S LAW The extension of an elastic body is directly proportional to the force causing the extension This is proved by stretching a spring with different weights. Graph these weights with the length the spring has extended . The points should make a straight line through the origin . This proves that the extension of an elastic body is directly proportional to the force causing the extension

HeatHeat

Difference between heat and temperatureDifference between heat and temperature

Difference between heat and Difference between heat and temperaturetemperature HeatHeat Heat is a form of energy.Heat is a form of energy. The unit used for heat is the joule (J)The unit used for heat is the joule (J) TemperatureTemperature Temperature is a measurement of the hotness Temperature is a measurement of the hotness

of a body.of a body. The unit used for temperature is the degree The unit used for temperature is the degree

Celsius (C)Celsius (C)

LatentLatent Heat Heat

Causes a change in state and not a change in Causes a change in state and not a change in temperature.temperature.

A solid might change to a liquid or a liquid might A solid might change to a liquid or a liquid might change to a gas.change to a gas.

ConductionConduction

Transfer of heat through a solid.Transfer of heat through a solid. Particles in the solid vibrate & transfer heat Particles in the solid vibrate & transfer heat

from one particle to another by conduction.from one particle to another by conduction. ExperimentExperiment

Conduction continuedConduction continued

Attach wax to the end of each rodAttach wax to the end of each rod Pour boiling water into metal containerPour boiling water into metal container The wax that melts on the rod first before The wax that melts on the rod first before

any other, is the best conductor of heat.any other, is the best conductor of heat. Result: Wax melts from the copper rod Result: Wax melts from the copper rod

first.first.

EXPANSION OF SOLIDS EXPANSION OF SOLIDS WHEN HEATED AND WHEN HEATED AND CONTRACT WHEN COOLEDCONTRACT WHEN COOLED

METHODMETHOD

1. SEE IF BALL FITS INTO RING. 1. SEE IF BALL FITS INTO RING. 2. THEN HEAT THE BALL WITH 2. THEN HEAT THE BALL WITH

BUNSEN.BUNSEN. 3. SEE IF BALL FITS INTO RING AGAIN 3. SEE IF BALL FITS INTO RING AGAIN

RESULTRESULT

THIS SHOWS THAT WHEN A SOLID IS THIS SHOWS THAT WHEN A SOLID IS HEATED IT EXPANDS.BALL DID NOT HEATED IT EXPANDS.BALL DID NOT FIT THROUGH RING.FIT THROUGH RING.

AND WHEN COOLED AND WHEN COOLED CONTRACTS.BALL FITS THROUGH CONTRACTS.BALL FITS THROUGH RING.RING.

EXPANSION OF LIQUIDS EXPANSION OF LIQUIDS WHEN HEATED AND WHEN HEATED AND CONTRACTION WHEN CONTRACTION WHEN COOLEDCOOLEDEXPERIMENTEXPERIMENT

METHODMETHOD

Fill a round bottomed flask with waterFill a round bottomed flask with water

that has been coloured.that has been coloured. Insert stopper with glass tube on top Insert stopper with glass tube on top

of flask.of flask. Hold flask with clamps.Hold flask with clamps. Heat water with bunsen burner.Heat water with bunsen burner.

resultresult

The coloured water rises up to the top of The coloured water rises up to the top of the test tube, due to heat (expansion).the test tube, due to heat (expansion).

Heat and solidsHeat and solids

The equipment needed from this is retort stand, ball The equipment needed from this is retort stand, ball and ring apparatus, Bunsen burner that is what is and ring apparatus, Bunsen burner that is what is

needed for this experiment.needed for this experiment.

Heat is a form of energy.Heat is a form of energy.

To test how to see that the ball fits To test how to see that the ball fits through the ring is when it is heated through the ring is when it is heated it expands but when it is cooled it it expands but when it is cooled it contracts so it will fit through the contracts so it will fit through the ring. The ball must cool for 10 ring. The ball must cool for 10 minutes before doing the minutes before doing the experiment. The ball should fit experiment. The ball should fit through the ring.through the ring.

ConclusionConclusion

The solid ball expanded when heated The solid ball expanded when heated and contracted when cooled.and contracted when cooled.

Result 1Result 1

The ball does not fit through the ring The ball does not fit through the ring as it expanded due to heat. Allow the as it expanded due to heat. Allow the ball to cool for about 10 minutes. See ball to cool for about 10 minutes. See if the ball fits through the ring now if the ball fits through the ring now that it has cooled. that it has cooled.

Result 2Result 2

The ball now fits through the ring as The ball now fits through the ring as it has contracted due to cooling.it has contracted due to cooling.

Heat and solidsHeat and solids

The equipment needed from this is retort stand, ball and ring The equipment needed from this is retort stand, ball and ring apparatus, Bunsen burner that is what is needed for this apparatus, Bunsen burner that is what is needed for this

experiment.experiment.

Heat is a form of energy.Heat is a form of energy.

To test how to see that the ball fits through To test how to see that the ball fits through the ring is when it is heated it expands but the ring is when it is heated it expands but when it is cooled it contracts so it will fit when it is cooled it contracts so it will fit through the ring. The ball must cool for 10 through the ring. The ball must cool for 10 minutes before doing the experiment. The minutes before doing the experiment. The ball should fit through the ring.ball should fit through the ring.

ConclusionConclusion

The solid ball expanded when heated and The solid ball expanded when heated and contracted when cooled.contracted when cooled.

Result 1Result 1

The ball does not fit through the ring as it The ball does not fit through the ring as it expanded due to heat. Allow the ball to cool expanded due to heat. Allow the ball to cool for about 10 minutes. See if the ball fits for about 10 minutes. See if the ball fits through the ring now that it has cooled. through the ring now that it has cooled.

Result 2Result 2

The ball now fits through the ring as it has The ball now fits through the ring as it has contracted due to cooling.contracted due to cooling.

To investigate conduction and convection in water

experiment

Method

Sink an ice cube to bottom of a test tube of water with the help of a weight (coin).

Heat the water at the top of the test tube with bunson burner.

Result 1

The water at the top of test tube can be boiling but the ice has not melted

Heat doesn’t travel down the water Water is a poor conductor.

Result 2

Remove coin and let ice float to the top of the test tube.

Heat the bottom of the test tube with bunsen burner.

Heating the bottom will melt the ice.Heat travels in water by convection.

EXPANSION OF GASES WHEN HEATED

EPUIPMENT

.Retort stand

.Round-bottomed flask

.Bunsen burner

.Glass tube

.Beaker of water with coloured food dye.

Expansion of gases

METHOD

1. Insert a stopper with a glass tube into the top of the flask.

2. Set up the apparatus with the retort stand.

3. Gently heat the round bottomed flask. Observe the glass tube.

RESULT

.The coloured water rises in the glass tube. As the air contracts the water is pulled up.

Why is the sun our primary Why is the sun our primary source of energysource of energy

Without the sun we would not have fossil Without the sun we would not have fossil fuels, when alive these plants and animals fuels, when alive these plants and animals needed the sun.needed the sun.

Photosynthesis is needed for plants.Photosynthesis is needed for plants.

Law of conservation of energyLaw of conservation of energy

Energy is neither created nor destroyed but Energy is neither created nor destroyed but can be converted from one form to another.can be converted from one form to another.

Luminous objectsLuminous objects

Luminous objects give out lightLuminous objects give out light

Non luminousNon luminous

Non luminous objects reflect lightNon luminous objects reflect light

REFRACTION

Refraction of light is the bending of light as it passes from one medium to another.

REFLECTION

LIGHT : Light can be reflected off almost every surface. It allows us to see non-luminous objects like books

SOUND : Sound reflects of certain surfaces and a good surface to reflect sound would be a smooth wall. An echo is an example of sound reflection.

SOUND AS A FORM OF ENERGY

SOUND AS A FORM OF ENERGY : When you hear someone talk at the far side of a room, sound energy travels from your vocal chords to your ears.

HOW SOUND IS PRODUCED

SOUND IS PRODUCED BY VIBRATIONSSound is made by vibrations as a speaker

vibrates and produces a sound. The reason we have a problem seeing them is because they move very fast and we cant see them but it is possible to see them.

WHITE LIGHTWHITE LIGHT

WHITE LIGHT IS MADE OF WHITE LIGHT IS MADE OF DIFFERENT COLOURSDIFFERENT COLOURS

Mrs. Lenane 2012

• Work hard• Play hard• Achieve the results you deserve.