191328 KS3 Science CH3 - Freedom to Teach...92 KS3 Science Book 1: Understanding Elements Chemistry...

86 KS3 Science Book 1: Understanding Elements

CHEMISTRY

Understanding Elements

Materials All substances are made of different materials. Materials have different properties; some are harder than others, some are shinier and some are heavier.

Glass, for example, is a very different material from plastic or metal.

Ideas you have met before ❯❯

Metals Metals are shiny solids that we use for many different things, such as making cars, computers, bridges and so on.

Metals are good electrical conductors, which is why we use them to make wires and circuits.

States of matter: solids, liquids and gases Most materials can be classifi ed into three groups: solids, liquids and gases.

Ice, water and steam are three states of matter of the same substance. We can convert materials from solids, liquids and gases by heating or cooling them.

Physical and chemical changes Melting ice is reversible. We can put it into a freezer and produce ice again. This is a physical change.

Some changes are not reversible. These are are called chemical changes. Making toast is a chemical change; you can’t change it back into bread.

191328 KS3 Science_CH3.indd 86 22/10/13 5:59 PM

87

Elements and atoms • Since ancient times materials have been described in

terms of the chemical elements that they contain.

• Ideas about elements have changed over time.

• Each element is unique, with its own properties.

The Periodic Table • The chemist’s dictionary is called the Periodic Table.

• The ingredients of the entire universe are listed in one place.

Using simple models • Chemists can represent the building blocks of all

materials using simple circle models and symbols.

• Chemical models and symbols help us understand how elements join and react together to make new materials.

Reactions • Chemical elements can join together in many ways to

produce an amazing range of different substances.

• We can make new materials by chemical reactions and then use them to do many different things.

In this chapter you will fi nd out ❯❯❯



Chemistry

Introducing the Periodic Table of elements

We are learning how to:

• Navigate the Periodic Table and identify some of the elements.

• Identify features of the Periodic Table and describe how it is organised.

• Explain why the Periodic Table is useful.

The Periodic Table lists all the known chemical elements in our universe. The patterns and trends in the arrangement help chemists explain and predict the behaviour, properties and reactions of all the elements.

FIGURE 1.3.4a: The Periodic Table of elements

The Periodic Table is arranged in rows called periods and columns called groups . Groups are families of elements with similar properties. Group 1 is the alkali metals, which all react quickly with water. The halogens are in Group 17; they are good at killing bacteria. The noble gases in Group 18 are all unreactive gases. These characteristics are called chemical trends and patterns.

Periods and groups ❯


93the Periodic Table

3 .4 Another pattern to recognise is that metals are on the left and non- metals, except hydrogen, are on the right. In between are metalloids, which have some of the properties of metals but not all.

1. How many groups make up the Periodic Table?

2. Name three families of elements.

3. The Periodic Table is split into three types of elements: what are they called?

Each element has unique number, called the Atomic number . This number increases left to right across each period. For example, hydrogen (H) is number one, lithium (Li) is number three, carbon (C) is number six and neon (Ne) is number 10. This is an important pattern in the Periodic Table.

4. Describe how the elements are arranged within the Periodic Table.

5. Use the Periodic Table to answer these questions:

a) In which group would you fi nd carbon (C)?

b) In which period would you fi nd magnesium (Mg)?

Most elements are solids at room temperature, which means that their melting point is higher than 20 °C. Only two are liquids at room temperature: mercury (Hg) and bromine (Br). The melting and freezing point of mercury is −39 °C. It would still be liquid if you put it in your freezer.

Oxygen (O) is a gas at room temperature, which means that it has a boiling point below 20 °C. To turn oxygen into a liquid you would have to cool it to below −183 °C.

6. Look at the elements in the table showing the melting and boiling points of fi ve different elements.

a) Which one has the lowest boiling point?

b) Which one has the highest melting point?

c) Which one is liquid at room temperature?

7. If the temperature dropped to below room temperature which element would freeze fi rst? Explain your choice.

8. What is the number of the element with a boiling point lower than oxygen?

Atomic number ❯❯

Melting and boiling ❯❯❯ Did you know . . . ?

Mercury is sometimes called quicksilver and is the only metal that is liquid at room temperature. It was named after the Roman messenger of the gods; its symbol Hg is derived from the Greek word hydrargyros which means silver water.

Key vocabulary

the Periodic Table

period

group

atomic number

Xenon name of elementelement state

chemical symbol

mass numberatomic number131.29 54

Xe

FIGURE 1.3.4b: Each element has a symbol, atomic number and mass number.

TABLE 1.3.4: Trends and patterns in melting and boiling points tell us about the physical state of elements at different temperatures

Melting point

Boiling point)

1 −210 °C −196 °C

2 −7 °C 59 °C

3 328 °C 1750 °C

4 1064 °C 2856 °C

5 115 °C 445 °C



Chemistry

Applying key ideas You have now met a number of important ideas in this topic. This activity is an opportunity for you to apply them, just as scientists do. Read the text fi rst, then have a go at the tasks. The fi rst few are fairly easy, then they get a bit more challenging.

How tinny is a tablet? If we call something ‘tinny’, we’re probably not being very kind about it. If you said that someone’s car was a bit tinny, they might not be very pleased, as it implies it isn’t very well made. Tin, however, is very important to us, and has been for thousands of years. It is a silvery metal which is both malleable and ductile.

Copper has been used for thousands of years to make tools, coins, weapons and decorations. It isn’t very hard, but it can be alloyed with tin to make bronze, which is much harder. Roman offi cers had swords made of bronze, and for many decades bronze was used to make ships’ propellers, until it was replaced by stainless steel.

For thousands of years one of the main sources of tin was Cornwall. At its height, in the 19 th century, the Cornish tin mining industry produced 10 000 tonnes of tin a year, from cassiterite, or tin ore, SnO 2 . The ore is crushed, washed, roasted to remove sulfur and arsenic as oxides, and then heated strongly with coal to produce pure tin.

Tin doesn’t easily react with oxygen and is used to coat other metals such as steel. A tin can isn’t made of tin but of steel coated with tin. Tin has a low melting point compared with other metals and is used to make solder, which is used to join electrical components together so that they make effective and permanent connections. When heated, the solder melts and fl ows onto the contacts; it then sets hard, fi xing the component into the circuit.

Every tablet contains thousands of soldered joints and, therefore, several grams of tin. In fact, it’s one of the most common metals used in their manufacture.

FIGURE 1.3.11a: Soldering

FIGURE 1.3.11b


107

3 .11

Task 4: Applications in electronic devices What is it about tin that makes it suitable for use as solder?

Task 3: Applications at sea What sometimes happens to metals in sea water? What do you think it was about bronze that made it suitable for making ships’ propellers?

Task 2: Thinking about alloys What is meant by an alloy? What has to happen to metals to turn them into an alloy? How did tin make copper more useful? Copper and tin aren’t often mined in the same area. Why did bronze depend upon trade?

Task 1: Exploring properties What does tin look like? Explain in simple terms what is meant by tin being silvery, malleable and ductile.

Task 5: Finding its family Find tin on the Periodic Table. What are its neighbours in that group? Research their properties and fi nd out what they have in common with tin.

Task 6: Thinking about its ore What is an ore? The formula of tin ore is SnO 2 . What does this formula tell you? Tin ore is roasted to drive off sulfur and arsenic as oxides. What would the names of the compounds formed be? Why would this be a dangerous process?



Chemistry We are learning how to:

• Draw conclusions to explain observations.

• Use symbols and models to describe a chemical reaction.

How an element reacts and the products it makes are unique to the element and the conditions. These differences can help chemists identify elements not only on Earth, but out in space, too.

Fireworks contain metals and non- metal compounds. It is the metals that are responsible for the colour; when they burn at high temperatures, they give off distinct colours.

TABLE 1.3.15

Metal Flame colour

potassium lilac

calcium yellow

iron orange

copper green/blue

magnesium white

strontium red

barium green

Carbon and sulfur combined act as a fuel that launches the fi rework and keeps it burning . When non- metals like these burn, they produce gases. Both sulfur dioxide and carbon dioxide dissolve in water to form acids . When metals burn the products are solid oxides that are the opposite of acids; these are called bases .

1. If an unknown compound turned a Bunsen fl ame green, what conclusion could you draw?

2. Which reactants will form the product sulfur dioxide?

3. What are the reactants if sodium oxide is produced?

4. How could you tell that it is sodium not sulfur burning?

Using fl ames to recognise metals ❯

Observing how elements react in different ways

FIGURE 1.3.15a: Fireworks use different metal compounds to produce different colours.

FIGURE 1.3.15b: Sodium burns with a yellow fl ame and produces a white powder called sodium oxide, Na 2 O.

O

SO O

Na Na

FIGURE 1.3.15c: Different oxide compounds.


115reacting elements and oxygen

3 .15 The temperature that substances are heated to is important. There has to be enough energy and air for elements to burn. The reaction not only forms an oxide, it also emits light. The colour of the light depends on the element, but the colour of the sparks produced by burning iron depends on the temperature. The colour changes from orange at lower temperatures to white when it is very hot.

Key changes indicate that a chemical reaction has happened:

• Has the substance permanently changed its appearance?

• Are there gas bubbles or a new smell?

• Has the temperature gone up or down? Can you feel heat?

• Change of pH – has an acid or base been produced?

5. List the substances found in fi reworks and the reasons they are included.

6. List the evidence for burning sulfur being a chemical reaction.

7. Explain the difference between melting iron and burning iron in as much detail as you can.

8. Write a word equation for the burning of iron.

Zinc is used in fi reworks to create smoke effects as zinc oxide (ZnO) is a non- toxic, fi ne white power. Zinc oxide is insoluble and is often used in sunscreens. Magnesium is used in fi reworks and sparklers as it produces bright white sparks and ultraviolet (UV) light. UV light is emitted by the Sun and can damage your eyes. It is the reason you wear sunglasses and protect your skin with sunscreen.

9. What are the advantages and disadvantages of using magnesium in fi reworks?

10. Use word equations and circle diagrams to represent the burning of zinc and magnesium in fi reworks.

Temperature matters ❯❯

White light and smoke ❯❯❯

Did you know . . . ?

Astronomers use special machines called spectrometers to study light that is emitted from distant stars and galaxies. Stars inside a nebula glow with beautiful reds, blues, and greens due to the different elements within the vast clouds of gas.

FIGURE 1.3.15d: Gas cloud nebula, galaxy and stars

Key vocabulary

fuel

burning

acid

product

base



Chemistry

It is important that scientists can make good observations and interpret information. They use their knowledge to explain what the patterns in data mean. Companies use scientists to fi nd out the best materials to use in new products.

Gallium is a non- toxic, shiny metallic element in Group 3, underneath aluminium. It melts in your hand because it has a low Melting point of 29.8 °C. It also shatters like glass if you hit it and it will attack metals like aluminium by forming alloys with them.

1. Why would gallium be a poor choice for a drink can?

2. Which properties are important in a drink can?

Some elements are toxic (poisonous) to humans, making us ill and even causing death over a certain amount. Metals like lead and mercury are stored in our bodies over time and are linked to problems with the brain and nervous system. They were used in the past in paints, dental fi llings, water pipes and make-up, until we realised how harmful they were.

The reactions of different metals with air and water vary. Some, like gold, don’t react with either. Group 1 elements like potassium react quickly with oxygen in air and violently with water. Aluminium reacts quickly with oxygen in air but the reaction forms a protective oxide layer over the metal which stops it reacting with anything else. Iron reacts slowly with air and water, forming rust, which weakens the metal.

3. Give two reasons why neither lead nor mercury would be good materials for a drink can.

4. Compare the use of gold and iron as materials for a drink can.

Density helps us understand how heavy substances are, compared to their volume. The greater the density, the heavier

Gallium ❯

Problems with metals ❯❯

Selecting the right metal ❯❯❯

We are learning how to:

• Recognise elements and their differences from physical data.

• Use data and the properties of elements to choose suitable materials.

Choosing elements for a purpose

FIGURE 1.3.10a: Gallium is a metal that melts in your hand

FIGURE 1.3.10b: Drink cans are made of metal


105properties of elements on the Periodic Table

3 .10the substance would be. If blocks of lead and aluminium of the same size were placed on the balance, the lead one would be heavier, because it has a greater density.

Sometimes the best material for the job is not chosen as it is too expensive. Silver is a better conductor of electricity than copper, but is only used in specialist items such as satellites.

Table 1.3.10 gives data about the properties of 10 elements, which tell us a lot about their appearance and behaviour.

TABLE 1.3.10

element Conducts heat

Conducts electricity

Melting point (°C)

Density (g/cm 3 )

Cost pure ($/g)

Other properties

graphite not well yes 3730 2.25 2.4 brittle

helium no no −270 0.15 5.2 inert

lead yes yes 327 11.30 2.5 poisonous

aluminium yes yes 660 2.70 15.7 protective layer

hydrogen no no −259 0.07 12.0 fl ammable

silver yes very well 961 10.50 120.0 shiny

gallium yes yes 29.8 5.91 5.0 poisonous

sodium yes yes 97.8 0.97 25.0 very reactive

iron yes yes 1535 7.86 7.2 rusts

copper yes very well 1083 8.92 9.8 non- toxic

5. Which of the elements in the table are not solids at room temperature (20 °C)?

6. a) Give one reason for and one against for using graphite to make a drink can.

b) Choose the material you think would be most suitable for a drink can and explain why.

c) Rank the elements in order from most suitable to least suitable.

7. Joe has suggested using copper to make his drink can because it conducts heat and electricity well and he likes the orange colour. Explain to Joe why his choice is good, but that there are better alternatives.

Did you know . . . ?

Gold jewellery and silver coins are ‘fake’! Nine carat gold is less than half gold as pure gold is too soft. 50p coins are 75 per cent copper and 25 per cent nickel, which is cheaper and harder than silver.

Key vocabulary

melting point

toxic

density

lead

(11.3 g/cm3)

aluminium(2.7 g/cm3)

FIGURE 1.3.10c: If different metals are each made into blocks of the same size, the denser one would be heavier.



KS3 Science Teacher Pack 1 © HarperCollinsPublishers Ltd 2014 25

3.2 Recognising materials, substances and elements

Lesson overview

Learning objectives

Recognise the difference between materials, substances and elements.

Identify elements by their names and symbols.

Explain what is meant by a chemically pure substance.

Learning outcomes

Classify substances as materials, pure substances, compounds or elements. [O1]

Interpret the names and symbols of common elements and compounds. [O2]

Explain the difference between pure and chemically pure substances. [O3]

Skills development

Thinking scientifically: Use units and nomenclature.

Working scientifically: Develop explanations.

Learner development: Ask questions.

Resources needed Range of substances, names, objects, labels

Common misconceptions Materials are all fabrics/clothing; water/orange juice are chemically pure or single substances.

Key vocabulary pure, element, compound, symbol, material

Teaching and learning

Engage

Identify students’ prior knowledge by giving them a series of different materials or pictures, e.g. bottle of water/pure orange juice carton, metal, plastic, glass, charcoal or graphite, wood, NaCl salt, fabric. Ask them to identify what the items are made of and then classify them into groups. [O1]

Explore the idea of materials being made of different substances by means of a group discussion. [O1]

More able students may make links to materials being made of particles by referencing prior knowledge of solids, liquids

and gases.

Challenge and develop

Ask students to identify the substances that are pure using questions such as, 'How do you know that substances are pure?' [O3]

Use the labels of water and orange juice packaging to make observations about the number of substances and conduct simple experiments, e.g. evaporate water to show residue of salts. [O1,2&3]

Ask students to list observations about names and symbols of materials e.g. iron nail (Fe), graphite (C), salt/sodium chloride (NaCl) using questions such as, 'Are they single pure substances?' [O2]

Discuss how the names and symbols give clues to their composition. Introduce the idea of elements being the simplest pure substances. [O1&2]

Explain

Show the Periodic Table and explain that it includes all the chemical elements (symbols as well as names); everything in the universe is made up of a combination of these elements, e.g. NaCl, called compounds. [O2]

Orientate students with the Periodic Table by choosing element symbols for them to find and name, e.g. Al, N, He, Pb. Ask, 'Which elements have you heard of?', 'What are their symbols?' [O2]



More able students may be able to predict symbols from names of elements and identify elements that have symbols not

linked to their English names, e.g. Lead (Pb); gold (Au).

Pair talk: Students should study the Periodic Table and identify similarities/differences, e.g. what do they notice about the symbols? Identify rules: always capital letter at start, 1 or 2 letters, none the same. [O2]

Ask students to explain why every element has a different symbol by asking, 'How would you recognise whether a substance was an element or a compound?' [O1]

Consolidate and apply

Ask students to classify substances, compounds and elements using symbols and record their observations on Worksheet 3.2. This will help to orientate and familiarise students with common names and symbols. [O1]

More able students should be challenged to explain, with correct terms and examples, the differences between a)

substance, element and compound; b) chemically pure and naturally pure substances.

Pair talk/Pairs to fours: Students should test each other on symbols or take turns to list as many element names as they can in 30 seconds. [O2]

Ask students to identify which elements they think may be present in the body. They should check their ideas against the table in the student book and collaborate to develop answers to the questions. [O1]

Extend

For students making greater than expected progress:

Ask questions about the relative size of elements: 'Which are bigger – elements/compounds or cells?'; 'What are cells made of?' [O1]

Consolidate understanding by making it clear that cells are made of chemical substances and structures. Explain that these cells are made of combinations of the 92 elements, therefore elements and compounds are much smaller than cells. (Particles as atoms are introduced later.) [O1]

Plenary suggestions

“I think that is…because…” Name various substances and ask students to identify them as materials, pure substances, compounds or elements. [O1,2&3]

Answers to Student Book 1 C

2 Two capital letters means two elements – in this case, hydrogen and oxygen. The number signifies two of hydrogen to every one of oxygen.

3 Carbon, hydrogen and oxygen

4 CO is a compound of carbon and oxygen; Co is an element (cobalt).

5 Chemically pure water contains only one substance/is a compound (H2O) but bottled water is a mixture of many substances.

6 It is a compound/single chemical substance made of three different elements joined together/has three capital letters, and therefore is not a single element.

7 'Pure' makes things sound natural, safe, clean and good for us.

8 Blood is a mixture of water, salts and haemoglobin. Haemaglobin is a compound/contains only one type of substance.

9 Graph (pie chart or bar chart) appropriately scaled (0.05%–65%) and containing symbols.

Answers to Worksheet 3.2 1 Evaporation

2 a) compound b) mixture c) element d) mixture e) element

3 It could be ground up, have water added to dissolve the soluble components, filtered and then have the water evaporated.

Getting the energy to move


1.2 Exploring a Healthy Diet

The importance of the food groups

1 Summarise the importance of each of the food groups

Food group Importance in the human body

Carbohydrate

Protein

Fats

Vitamins

Minerals

Fibre

Water

Which food groups?

2 For each of the people below, decide which food group(s) would be most important for them.

a A builder needing lots of energy to work b A person suffering from constipation c A male model wanting to build up his muscles

Diet or supplements?

You have a friend who has a very poor diet, eating lots of crisps and chocolate and hardly any fruit or vegetables. They tell you that they have vitamin supplements and so don’t need to worry about what they eat.

3 Write a letter to your friend explaining why they should also think about eating a healthier diet.



3.6 Finding the density of an irregularly shaped object

In this practical you will find the density of an irregularly shaped object.

Apparatus

balance

measuring cylinder wide and deep enough to hold object

irregularly shaped object

SAFETY INFORMATION

Water is a suitable liquid for this investigation.

Method

1 Find the mass, m, of the object using a balance as shown.

Record its mass.

2 Choose a measuring cylinder that is wide and deep enough to hold the object.

3 Add liquid to fill the cylinder to a deep enough level so that the object will be completely submerged.

4 Measure the volume of liquid, V1. Record it.

5 Lower the object into the liquid (without splashing).

6 Measure the new volume V2. Record it.

Analyse and interpret data

7 Calculate the volume of the object V2 – V1. Record it. Calculate the volume of the object V2 – V1. Record it.

8 Calculate the density of the object from the mass and the volume. Record it.

9 Why will a narrower cylinder give a more accurate answer than a wider one?

10 Why is the volume of the object V2 – V1?

Evaluate data and methods

11 How could you check your value for the density?

12 Why is it important that you do not splash when lowering the object into the liquid?

a) How could you check your value for the density?

b) Why is it important that you do not splash when lowering the object into the liquid?

d) How could you check your value for the density?

Electricity and magnetism


6.3 Materials, substances and elements

Technician’s notes

Be sure to check the latest safety notes on these resources before proceeding

The following resources are needed for the class demonstrations, P2b.1:

Introduction

pictures of typical electrical hazards – frayed cables, over-long cables, damaged plugs, damaged sockets, water near sockets, incorrect objects inserted into sockets, metal object put into objects such as toasters, overloaded sockets (through use of multiplugs).

access to the laboratory's RCCB

Earth safety

12 V AC supply with earthing point

ray box lamp with metal outer casing

coil of 5 A fuse wire

two red 4 mm leads, black 4 mm lead, green or yellow 4 mm lead, brown 4 mm lead, blue 4 mm lead

heatproof mat

two crocodile clips

The power pack needs to supply at least 6 A to ensure that the fuse blows.

Check that the voltage used is sufficient to blow the fuse before the activity.

The following resources are needed for the class practical P2b.1a, per group

20 mm glass bodied fuse rated at 800 mA

12 V ray box lamp or similar

ammeter (0–1 A)

four 4 mm leads

two crocodile clips

variable DC power supply for ray box

The lamp needs to be rated at 12 W or 24 W, so that the fuse blows before the lamp does. Subdued lighting makes it easier for the students to observe the glow of the fuse just before it melts.

Take care as the fuse is very hot.

Key Stage 3 Science Overview of Structure

©HarperCollinsPublishers 2013

BOOK 1

B1 Cells

Cells and organisation

Cells as the fundamental unit of living organisms, use of light microscope

The functions of the cell wall, cell membrane, cytoplasm, nucleus, vacuole, mitochondria and chloroplasts

The similarities and differences between animal and plant cells

The role of diffusion The structural adaptations of some

unicellular organisms Hierarchical organisation of

multicellular organisms Reproduction

Reproduction in humans (as an example of a mammal)

Reproduction in plants

B2 Eating, drinking, breathing

The breathing (gas exchange) system

The structure and functions of the gas exchange system in humans, including adaptations to function

The mechanism of breathing, using a pressure model

The impact of exercise, asthma and smoking

Human nutrition and digestion

Content in a healthy human diet Calculations of energy requirements

in a healthy daily diet The consequences of imbalances in

the diet The tissues and organs of the

digestive system The importance of bacteria in the

digestive system C1 Understanding elements

The Periodic Table

The principles underpinning the Mendeleev Periodic Table

The chemical properties of metals and non-metals

Chemical symbols and formulae Atoms, elements and compounds

Differences between atoms, elements and compounds

The difference between chemical and physical changes

Concept of a chemical reaction; combustion as an example

C2 Mixing, separating and reacting

Pure and impure substances

Mixtures including dissolving Techniques for separating mixtures The identification of pure substances Conservation of mass changes of

state and chemical reactions. Chemical reactions

Combustion, thermal decomposition and oxidation reactions

P1 Forces and their effects

Forces

Forces as pushes or pulls, the interaction between two objects

Moment as the turning effect of a force

Using force arrows in diagrams, balanced and unbalanced forces

Forces associated with deforming objects

Forces and motion

Forces being needed to cause objects to move (qualitative only)

Speed = distance ÷ time Hooke's Law as a special case Work done and energy changes on

deformation

P2 Energy transfers and sound

Changes and transfers

Examples of processes that cause change, work = force x distance

Fuel, fuel sources and heating Energy and waves

Sound waves carrying energy Sound waves

Frequencies; echoes, reflection and absorption of sound

The speed of sound in air Sound produced by vibrations of

objects Auditory range of humans and

animals



BOOK 2

B1 Getting the energy to move

Cellular respiration

Aerobic and anaerobic respiration in living organisms

The word equation for aerobic respiration

The word equation for anaerobic respiration

The differences between aerobic and anaerobic respiration

The skeletal and muscular systems

The structure and functions of the human skeleton

Biomechanics The function and antagonistic actions

of major muscle groups

B2 Interdependence and plants

Photosynthesis

The reactants in, and products of, photosynthesis

The dependence of almost all life on Earth on photosynthesis

The adaptations of leaves for photosynthesis

Relationships in an ecosystem

The interdependence of organisms The importance of plant reproduction

through insect pollination in human food security

How organisms affect, and are affected by, their environment

The role of variation C1 Explaining physical changes

The particulate nature of matter

The properties of states of matter Particle model

Particles explaining changes of state, shape, density and diffusion

A simple (Dalton) atomic model Physical changes

The difference between chemical and physical changes

Conservation of material and of mass, and reversibility

Brownian motion in gases Diffusion in liquids and gases driven

by differences in concentration Energy in matter

Changes with temperature in motion and spacing of particles

Energy changes on changes of state

C2 Explaining chemical changes

Chemical reactions

Combustion Chemical reactions as the

rearrangement of atoms Representing chemical reactions

using formulae and using equations What catalysts do

Acids, alkalis and neutralisation

Defining acids, bases and alkalis in terms of neutralisation reactions

Indicators and the pH scale for measuring acidity/alkalinity

Reactions of acids with metals to produce a salt plus hydrogen

Reactions of acids with alkalis to produce a salt plus water

P1 Pressure and non-contact forces

Static electricity

Non-contact forces Separation of positive or negative

charges The idea of electric field Gravity forces acting at a distance on

Earth and in space Pressure forces

Atmospheric pressure Pressure in liquids Pressure measured by ratio of force

over area – acting in all directions

P2 Electricity and magnetism

Current electricity

Electric current, circuits Potential difference Differences in resistance Calculations of current, power and

energy transfer for series circuits Magnetism

Magnetic poles, attraction and repulsion; magnetic fields

Earth’s magnetism, compass and navigation

The magnetic effect of a current, electromagnets, D.C. motors



BOOK 3

B1 Genetics

Inheritance, chromosomes, DNA and genes

Heredity as a process A simple model of chromosomes,

genes and DNA in heredity Variation between species and

between individuals Variation and extinction The importance of biodiversity The use of gene banks

B.2 Health and drugs

Microbes and disease

Embed and develop ideas from earlier units, including cell structure and function and body systems

Health, microbes and disease The effects of ‘recreational’ drugs

C1 Extracting useful materials

Chemical reactions

Displacement reactions Materials

The order of metals and carbon in the reactivity series

The use of carbon in obtaining metals from metal oxides

Ceramics, polymers and composites

C2 Responsible use of materials

Earth science

The composition of the Earth and the atmosphere; impact of humans

The structure of the Earth; the rock cycle

Earth as a source of limited resources

The carbon cycle Energy in matter

Internal energy stored in materials Energetics

Exothermic and endothermic chemical reactions (qualitative)

P1 Balanced forces and motion

Describing motion

The representation of a journey on a distance-time graph

Relative motion: trains and cars passing one another

Balanced forces

Opposing forces and equilibrium Space Physics

Gravity force, weight = mass x gravitational field strength (g)

Our sun as a star, other stars in our galaxy, other galaxies

The seasons and the Earth’s tilt The light year as a unit of

astronomical distance

P2 Waves and auditing transfers

Light waves

The similarities and differences between light and waves in matter

Light waves travelling through a vacuum; speed; transmission

Use of ray model Colour and frequencies of light

Energy and fuel

Energy in a domestic context; in food Relationship between rate of transfer

and amount of energy used Heating and thermal equilibrium

Auditing change

Energy as a quantity that can be quantified and calculated

Audit calculations using measures of change in the energy

Rates of change in W and kW Please note this is an over view only, and subject to minor changes pre-publication.

191328 KS3 Science CH3 - Freedom to Teach...92 KS3 Science Book 1: Understanding Elements Chemistry...

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