Original source · Published 11 September 2013 · Updated 2 December 2014

Science - Key stage 3

Introduction

The principal focus of science teaching in key stage 3 is to develop a deeper understanding of a range of scientific ideas in the subject disciplines of biology, chemistry and physics. Pupils should begin to see the connections between these subject areas and become aware of some of the big ideas underpinning scientific knowledge and understanding. Examples of these big ideas are the links between structure and function in living organisms, the particulate model as the key to understanding the properties and interactions of matter in all its forms, and the resources and means of transfer of energy as key determinants of all of these interactions. They should be encouraged to relate scientific explanations to phenomena in the world around them and start to use modelling and abstract ideas to develop and evaluate explanations.

Pupils should understand that science is about working objectively, modifying explanations to take account of new evidence and ideas and subjecting results to peer review. Pupils should decide on the appropriate type of scientific enquiry to undertake to answer their own questions and develop a deeper understanding of factors to be taken into account when collecting, recording and processing data. They should evaluate their results and identify further questions arising from them.

‘Working scientifically’ is described separately at the beginning of the programme of study, but must always be taught through and clearly related to substantive science content in the programme of study. Teachers should feel free to choose examples that serve a variety of purposes, from showing how scientific ideas have developed historically to reflecting modern developments in science.

Pupils should develop their use of scientific vocabulary, including the use of scientific nomenclature and units and mathematical representations.

Working scientifically

Through the content across all three disciplines, pupils should be taught to:

Scientific attitudes

• pay attention to objectivity and concern for accuracy, precision, repeatability and reproducibility
• understand that scientific methods and theories develop as earlier explanations are modified to take account of new evidence and ideas, together with the importance of publishing results and peer review
• evaluate risks.

Experimental skills and investigations

• ask questions and develop a line of enquiry based on observations of the real world, alongside prior knowledge and experience
• make predictions using scientific knowledge and understanding
• select, plan and carry out the most appropriate types of scientific enquiries to test predictions, including identifying independent, dependent and control variables, where appropriate
• use appropriate techniques, apparatus, and materials during fieldwork and laboratory work, paying attention to health and safety
• make and record observations and measurements using a range of methods for different investigations; and evaluate the reliability of methods and suggest possible improvements
• apply sampling techniques.

Analysis and evaluation

• apply mathematical concepts and calculate results
• present observations and data using appropriate methods, including tables and graphs
• interpret observations and data, including identifying patterns and using observations, measurements and data to draw conclusions
• present reasoned explanations, including explaining data in relation to predictions and hypotheses
• evaluate data, showing awareness of potential sources of random and systematic error
• identify further questions arising from their results.

Measurement

• understand and use SI units and IUPAC (International Union of Pure and Applied Chemistry) chemical nomenclature
• use and derive simple equations and carry out appropriate calculations
• undertake basic data analysis including simple statistical techniques.

Subject content – Biology

Pupils should be taught about:

Structure and function of living organisms

Cells and organisation

• cells as the fundamental unit of living organisms, including how to observe, interpret and record cell structure using a light microscope
• the functions of the cell wall, cell membrane, cytoplasm, nucleus, vacuole, mitochondria and chloroplasts
• the similarities and differences between plant and animal cells
• the role of diffusion in the movement of materials in and between cells
• the structural adaptations of some unicellular organisms
• the hierarchical organisation of multicellular organisms: from cells to tissues to organs to systems to organisms.

The skeletal and muscular systems

• the structure and functions of the human skeleton, to include support, protection, movement and making blood cells
• biomechanics – the interaction between skeleton and muscles, including the measurement of force exerted by different muscles
• the function of muscles and examples of antagonistic muscles.

Nutrition and digestion

• content of a healthy human diet: carbohydrates, lipids (fats and oils), proteins, vitamins, minerals, dietary fibre and water, and why each is needed
• calculations of energy requirements in a healthy daily diet
• the consequences of imbalances in the diet, including obesity, starvation and deficiency diseases
• the tissues and organs of the human digestive system, including adaptations to function and how the digestive system digests food (enzymes simply as biological catalysts)
• the importance of bacteria in the human digestive system
• plants making carbohydrates in their leaves by photosynthesis and gaining mineral nutrients and water from the soil via their roots.

Gas exchange systems

• the structure and functions of the gas exchange system in humans, including adaptations to function
• the mechanism of breathing to move air in and out of the lungs, using a pressure model to explain the movement of gases, including simple measurements of lung volume
• the impact of exercise, asthma and smoking on the human gas exchange system
• the role of leaf stomata in gas exchange in plants.

Reproduction

• reproduction in humans (as an example of a mammal), including the structure and function of the male and female reproductive systems, menstrual cycle (without details of hormones), gametes, fertilisation, gestation and birth, to include the effect of maternal lifestyle on the foetus through the placenta
• reproduction in plants, including flower structure, wind and insect pollination, fertilisation, seed and fruit formation and dispersal, including quantitative investigation of some dispersal mechanisms.

Health

• the effects of recreational drugs (including substance misuse) on behaviour, health and life processes.

Material cycles and energy

Photosynthesis

• the reactants in, and products of, photosynthesis, and a word summary for photosynthesis
• the dependence of almost all life on Earth on the ability of photosynthetic organisms, such as plants and algae, to use sunlight in photosynthesis to build organic molecules that are an essential energy store and to maintain levels of oxygen and carbon dioxide in the atmosphere
• the adaptations of leaves for photosynthesis.

Cellular respiration

• aerobic and anaerobic respiration in living organisms, including the breakdown of organic molecules to enable all the other chemical processes necessary for life
• a word summary for aerobic respiration
• the process of anaerobic respiration in humans and micro-organisms, including fermentation, and a word summary for anaerobic respiration
• the differences between aerobic and anaerobic respiration in terms of the reactants, the products formed and the implications for the organism.

Interactions and interdependencies

Relationships in an ecosystem

• the interdependence of organisms in an ecosystem, including food webs and insect pollinated crops
• the importance of plant reproduction through insect pollination in human food security
• how organisms affect, and are affected by, their environment, including the accumulation of toxic materials.

Genetics and evolution

Inheritance, chromosomes, DNA and genes

• heredity as the process by which genetic information is transmitted from one generation to the next
• a simple model of chromosomes, genes and DNA in heredity, including the part played by Watson, Crick, Wilkins and Franklin in the development of the DNA model
• differences between species
• the variation between individuals within a species being continuous or discontinuous, to include measurement and graphical representation of variation
• the variation between species and between individuals of the same species means some organisms compete more successfully, which can drive natural selection
• changes in the environment may leave individuals within a species, and some entire species, less well adapted to compete successfully and reproduce, which in turn may lead to extinction
• the importance of maintaining biodiversity and the use of gene banks to preserve hereditary material.

Subject content – Chemistry

Pupils should be taught about:

The particulate nature of matter

• the properties of the different states of matter (solid, liquid and gas) in terms of the particle model, including gas pressure
• changes of state in terms of the particle model.

Atoms, elements and compounds

• a simple (Dalton) atomic model
• differences between atoms, elements and compounds
• chemical symbols and formulae for elements and compounds
• conservation of mass changes of state and chemical reactions.

Pure and impure substances

• the concept of a pure substance
• mixtures, including dissolving
• diffusion in terms of the particle model
• simple techniques for separating mixtures: filtration, evaporation, distillation and chromatography
• the identification of pure substances.

Chemical reactions

• chemical reactions as the rearrangement of atoms
• representing chemical reactions using formulae and using equations
• combustion, thermal decomposition, oxidation and displacement reactions
• defining acids and alkalis in terms of neutralisation reactions
• the pH scale for measuring acidity/alkalinity; and indicators
• reactions of acids with metals to produce a salt plus hydrogen
• reactions of acids with alkalis to produce a salt plus water
• what catalysts do.

Energetics

• energy changes on changes of state (qualitative)
• exothermic and endothermic chemical reactions (qualitative).

The Periodic Table

• the varying physical and chemical properties of different elements
• the principles underpinning the Mendeleev Periodic Table
• the Periodic Table: periods and groups; metals and non-metals
• how patterns in reactions can be predicted with reference to the Periodic Table
• the properties of metals and non-metals
• the chemical properties of metal and non-metal oxides with respect to acidity.

Materials

• the order of metals and carbon in the reactivity series
• the use of carbon in obtaining metals from metal oxides
• properties of ceramics, polymers and composites (qualitative).

Earth and atmosphere

• the composition of the Earth
• the structure of the Earth
• the rock cycle and the formation of igneous, sedimentary and metamorphic rocks
• Earth as a source of limited resources and the efficacy of recycling
• the carbon cycle
• the composition of the atmosphere
• the production of carbon dioxide by human activity and the impact on climate.

Subject content – Physics

Pupils should be taught about:

Energy

Calculation of fuel uses and costs in the domestic context

• comparing energy values of different foods (from labels) (kJ)
• comparing power ratings of appliances in watts (W, kW)
• comparing amounts of energy transferred (J, kJ, kW hour)
• domestic fuel bills, fuel use and costs
• fuels and energy resources.

Energy changes and transfers

• simple machines give bigger force but at the expense of smaller movement (and vice versa): product of force and displacement unchanged
• heating and thermal equilibrium: temperature difference between two objects leading to energy transfer from the hotter to the cooler one, through contact (conduction) or radiation; such transfers tending to reduce the temperature difference: use of insulators
• other processes that involve energy transfer: changing motion, dropping an object, completing an electrical circuit, stretching a spring, metabolism of food, burning fuels.

Changes in systems

• energy as a quantity that can be quantified and calculated; the total energy has the same value before and after a change
• comparing the starting with the final conditions of a system and describing increases and decreases in the amounts of energy associated with movements, temperatures, changes in positions in a field, in elastic distortions and in chemical compositions
• using physical processes and mechanisms, rather than energy, to explain the intermediate steps that bring about such changes.

Motion and forces

Describing motion

• speed and the quantitative relationship between average speed, distance and time (speed = distance ÷ time)
• the representation of a journey on a distance-time graph
• relative motion: trains and cars passing one another.

Forces

• forces as pushes or pulls, arising from the interaction between two objects
• using force arrows in diagrams, adding forces in one dimension, balanced and unbalanced forces
• moment as the turning effect of a force
• forces: associated with deforming objects; stretching and squashing – springs; with rubbing and friction between surfaces, with pushing things out of the way; resistance to motion of air and water
• forces measured in newtons, measurements of stretch or compression as force is changed
• force-extension linear relation; Hooke’s Law as a special case
• work done and energy changes on deformation
• non-contact forces: gravity forces acting at a distance on Earth and in space, forces between magnets and forces due to static electricity.

Pressure in fluids

• atmospheric pressure, decreases with increase of height as weight of air above decreases with height
• pressure in liquids, increasing with depth; upthrust effects, floating and sinking
• pressure measured by ratio of force over area – acting normal to any surface.

Balanced forces

• opposing forces and equilibrium: weight held by stretched spring or supported on a compressed surface.

Forces and motion

• forces being needed to cause objects to stop or start moving, or to change their speed or direction of motion (qualitative only)
• change depending on direction of force and its size.

Waves

Observed waves

• waves on water as undulations which travel through water with transverse motion; these waves can be reflected, and add or cancel – superposition.

Sound waves

• frequencies of sound waves, measured in hertz (Hz); echoes, reflection and absorption of sound
• sound needs a medium to travel, the speed of sound in air, in water, in solids
• sound produced by vibrations of objects, in loud speakers, detected by their effects on microphone diaphragm and the ear drum; sound waves are longitudinal
• auditory range of humans and animals.

Energy and waves

• pressure waves transferring energy; use for cleaning and physiotherapy by ultra-sound; waves transferring information for conversion to electrical signals by microphone.

Light waves

• the similarities and differences between light waves and waves in matter

• light waves travelling through a vacuum; speed of light

• the transmission of light through materials: absorption, diffuse scattering and specular reflection at a surface

• use of ray model to explain imaging in mirrors, the pinhole camera, the refraction of light and action of convex lens in focusing (qualitative); the human eye

• light transferring energy from source to absorber leading to chemical and electrical effects; photo-sensitive material in the retina and in cameras

• colours and the different frequencies of light, white light and prisms (qualitative only); differential colour effects in absorption and diffuse reflection.

Electricity and electromagnetism

Current electricity

• electric current, measured in amperes, in circuits, series and parallel circuits, currents add where branches meet and current as flow of charge
• potential difference, measured in volts, battery and bulb ratings; resistance, measured in ohms, as the ratio of potential difference (p.d.) to current
• differences in resistance between conducting and insulating components (quantitative).

Static electricity

• separation of positive or negative charges when objects are rubbed together: transfer of electrons, forces between charged objects
• the idea of electric field, forces acting across the space between objects not in contact.

Magnetism

• magnetic poles, attraction and repulsion
• magnetic fields by plotting with compass, representation by field lines
• Earth’s magnetism, compass and navigation
• the magnetic effect of a current, electromagnets, D.C. motors (principles only).

Matter

Physical changes

• conservation of material and of mass, and reversibility, in melting, freezing, evaporation, sublimation, condensation, dissolving
• similarities and differences, including density differences, between solids, liquids and gases
• Brownian motion in gases
• diffusion in liquids and gases driven by differences in concentration
• the difference between chemical and physical changes.

Particle model

• the differences in arrangements, in motion and in closeness of particles explaining changes of state, shape and density, the anomaly of ice-water transition
• atoms and molecules as particles.

Energy in matter

• changes with temperature in motion and spacing of particles
• internal energy stored in materials.

Space physics

• gravity force, weight = mass x gravitational field strength (g), on Earth g=10 N/kg, different on other planets and stars; gravity forces between Earth and Moon, and between Earth and Sun (qualitative only)
• our Sun as a star, other stars in our galaxy, other galaxies
• the seasons and the Earth’s tilt, day length at different times of year, in different hemispheres
• the light year as a unit of astronomical distance.