4.1 Building blocks 4.1.1 States of matter Spec ref. Summary of the specification content Learning outcomes What most candidates should be able to do Suggested timing (hours) Opportunities to develop scientific communication and mathematical skills Opportunities to apply practical and enquiry skills Self/peer assessment Opportunities and resources Reference to past questions that indicate success 4.1.1.1 The three states of matter are solid, liquid and gas. Melting and freezing take place at the melting point, boiling and condensing take place at the boiling point. The three states of matter can be represented by a simple model. In this model, particles are represented by small solid spheres. Particle theory can help to explain melting, boiling, freezing and condensing. (HT only) Limitations of the simple model include that there are no forces between the spheres, and that Recall and explain the main features of the particle model in terms of the states of matter and change of state, distinguishing between physical and chemical changes. (HT only) Explain the limitations of the particle model in relation to changes of state when particles are represented by inelastic spheres. 1 Building blocks circus – to help pupils deduce the over-arching for this unit. Pupils choreograph showing particles in a substance such as water, as it changes state. What is the difference between melting and dissolving? WS 1.2 Recognise/draw simple diagrams to model the difference between substances in the solid, liquid and gas states. Describe and explain the different particle arrangements in solids, liquids and gases due to the bonds between the atoms. If you have a kinetic model, you can use it to demonstrate the motion of particles in a liquid/gas. Or use a tray filled with ping-pong balls and shake it. You can vary the number of ping-pong balls to demonstrate the three states. New Horizons – Pluto. 'Exotic ices' have been discovered on Pluto – what might this mean? Discussion question: Is baking a cake chemistry?
kg volume, V, in metres cubed, m3 to changes where mass is conserved. ice has a lower density than water. Draw diagrams to show the particle arrangement of solids, liquids and Use the diagrams to explain the differences in densities between solids, liquids and gases MS 1a, 1b, 1c, 3c Recall and apply the equation: to changes where mass is conserved. particle model of matter lesson. Evaluate the models used to explain the properties of solids, liquids and Required practical 1: use appropriate apparatus to make and record the densities of regular and irregular solid objects and liquids. Volume should be determined from the dimensions of a regularly shaped object and by a displacement technique for irregularly shaped objects. Dimensions to be measured using appropriate apparatus such as a ruler, micrometer or Vernier callipers. Physics AT 1
4.1.1.3 The molecules of a gas are in constant random motion. The temperature of the gas is related to the average kinetic energy of the molecules. The higher the temperature, the greater the average kinetic energy and so the faster the average speed of the molecules. Describe the motion of molecules within a gas. Describe and explain how the motion of molecules in a gas changes as the gas is heated. Explain why molecules in a gas that are moving faster have a higher temperature. 1 How does the temperature of a gas affect the movement of the particles within it? Why are gas cylinders likely to explode in a fire? To investigate the motion of gas molecules you can conduct a Brownian motion experiment using smoke cells viewed under a microscope. To carry out the experiment use Institute of Physics’ Episode 601-1: Video clip 4.1.1.3 cont. When the molecules collide with the wall of their container they exert a force on the wall. The total force exerted by all of the molecules inside the container on a unit area of the walls is the gas pressure. Describe why gases exert a force on a container. Explain what is meant by gas pressure in terms of the forces exerted by the gas molecules on a given area. 0.5 Explain in terms of gas pressure how blowing up a balloon too much can cause it to pop. Research how the gas pressure in a submarine stops it from crushing at depth. Use PhET interactive simulations to model gas pressure: 4.1.1.3 cont. Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas Describe and explain how changing the temperature of gas increases the gas pressure inside the container. 1 Pupils develop and evaluate analogies that use people to represent particles in a gas, eg 'Beatlemania'; home crowd at Wembley; the effects of methods of crowd control. What does a barometer measure and how does it work? Have two sealed syringes: one filled with the other with air. Video clip: YouTube:
needed to change the state of the substance. Evaluate data on the melting points and boiling points of different substances linked to the strength of the forces between the particles. Explain what is happening at each stage of the heating curve produced. temperature against time. 4.1.1.4 cont. The increase in temperature of a system depends on the mass of the substance heated, the type of material and the energy input. The following equation, given on the Physics equations sheet, applies: Define the term specific heat capacity and distinguish between it and the term specific latent heat. MS1a, 3c, 3d Use this equation to calculate energy changes during changes of state. 1 Describe and explain how the amount of water in a kettle affects how quickly it boils. Explain why a pan of cooking oil heats up faster than a pan of water, with the same mass of each, in terms of specific heat capacity. Why does a half-full kettle boil faster than a full one? Why do sea breezes change direction day and night? Plan a practical to investigate the rate of heating of various metals using a joulemeter to determine the energy input. If no joulemeter is available, use an ammeter, I, a voltmeter, V, and heat the material for a fixed amount of time, t. Calculate the energy transferred, E, using:
energy) but not the temperature. The energy needed for a substance to change state is called latent heat. When a change of state occurs, the energy supplied changes the energy stored (internal energy) but not the temperature. Interpret heating and cooling graphs that include changes of state. MS 1a, 3c, 3d Use this equation to calculate energy changes when a material is heated. 4.1.1.5 In chemistry, a pure substance is a single element or compound, not with any other substance. Pure elements and compounds melt and boil at specific temperatures. Melting and boiling point data can be used to distinguish pure substances from mixtures. In everyday language, a pure substance can Explain what is meant by the purity of a substance, distinguishing between the scientific and everyday use of the term ‘pure’. 0.5 WS 3.5 Use melting point data to distinguish pure from impure substances. Pupils investigate the effect of table salt on the melting point and boiling point of water.
4.1.2.1 Stages in the development of atomic models: Dalton atoms (1804) – spherical atoms that cannot be split up to explain the properties of gases and the formulae of compounds Plum pudding (1897) – it was found that the mass of electrons, which had recently been discovered, was very much less than the mass of atoms so they must be particles the nuclear atom (1911) – an experiment which showed that most of the alpha particles directed at thin gold foil passed through Describe how and why the atomic model has changed over time. Describe the difference between the plum-pudding model of the atom and the nuclear model of the atom. Describe why the new evidence from the scattering experiment led to a change in the atomic model. 1 Create a timeline for the history of the atomic model. Extended writing: Describe the differences between the plum-pudding model, nuclear model and atomic model. Describe why changes to the atomic model happened. High demand: Describe the experimental techniques involved in the history of the atomic model. Explain how the experimental techniques work. WS 1.1 Explain, with examples, why new data from experiments or observations led to changes in atomic models. WS 1.1 Decide whether or not given data supports a particular theory.
The number of protons in an atom of an element is its atomic number. All atoms of a particular element have the same number of protons. Atoms of different elements have different numbers of protons. In an atom the number of electrons is equal to the number of protons in the nucleus. Atoms have no overall electrical charge. Use the periodic table to identify number of protons in different elements. Describe the relationship between number of positive and negative charges. Apply this relationship to explain why there is no overall charge. Referring to their table of data students write their rules to state what the atomic number is and why elements are different from each other. Extended writing: Describe the structure of atoms. 4.1.2.4 The sum of the protons and neutrons in an atom is its mass number. of the same element can have different numbers of neutrons; these atoms are called isotopes of that element. Relate differences between isotopes to differences in conventional representations of their identities, charges and masses. 0.5 WS 1.2 Calculate numbers of protons, neutrons and electrons in atoms and ions, given atomic number and mass number of isotopes.
4.1.3 Cells in animals and plants Spec ref. Summary of the specification content Learning outcomes What most candidates should be able to do Suggested timing (hours) Opportunities to develop scientific communication skills Opportunities to apply practical and enquiry skills Self/peer assessment Opportunities and resources Reference to past questions that indicate success 4.1.3.1 An electron microscope has a much higher resolving than a light microscope. This means that it can be used to study cells in much finer detail. An electron microscope can magnify up to a million times (× 1000 000) or more, which is much more than a light microscope which has a useful magnification of only about a thousand times (× 1000). Describe the differences in magnification and resolution of light and electron microscopes. Explain how electron microscopy has increased understanding of organelles. Calculate the magnification of a light microscope. Carry out calculations using the formula: Rearrange the equation to calculate image size or magnification. Convert values for the units: cm, mm, µm and nm 1 Use a variety of resources to research the differences between a light microscope and an electron microscope. Use online materials to make a display of cell images from a light microscope and from an electron microscope. Write a newspaper article entitled: ‘Microscope…..the best invention ever!’ where pupils explain the significance of the microscope and discuss what the world would be like if microscopes were never invented. Calculate the real size of microscope images, and convert units as appropriate. Rearrange the equation to calculate a different unknown. Use online and printed materials to calculate the real of cells and structures. Limited to the differences in magnification and resolution. MS 1a,1b, 1c, 2h Carry out calculations involving magnification, real size and image size ((HT only) including numbers written in standard form). WS4.4 Use prefixes centi-, milli-, micro- and nano-. MS 1d, 2h Make order of magnitude calculations. Extension work: Use a microscope with graticule to measure Observation activity materials: microscope graticule prepared slides calculator.
a permanent vacuole filled with cell sap. and algal cells also have a cell wall made of cellulose, which strengthens the cell. 4.1.3.3 Some substances move across cell membranes via diffusion. Diffusion is a spreading out and mixing process. Particles move from a region where they are in higher concentration to a region where their concentration is lower. Factors that affect the rate of diffusion across a membrane are: the difference in concentration the temperature the surface area of the membrane. Define the term ‘diffusion’. Explain how temperature, concentration gradient and surface area affect the rate of diffusion. 1 Observe demos and suggest explanations: Time how long it is before pupils can smell a perfume placed in a corner of the room. Is the rate of diffusion different for different Use concentrated ammonium hydroxide and hydrochloric acid in a large glass tube. Does temperature affect the rate of diffusion? Fresh beetroot placed in iced water and warm water. Record observations and suggest explanations. Choose investigations as appropriate: potassium permanganate in beaker of water, potassium permanganate on agar investigate diffusion of different acids and alkalis through agar investigate rate of diffusion of glucose through cellulose tubing use digital microscope to observe diffusion of particles in milk or yogurt solution. Demo materials: strong perfume concentrated concentrated HCl gloves mask forceps cotton wool long glass tube with strips of damp litmus along length beetroot beakers kettle ice two gas jars of NO2
Watch a video or computer simulation of diffusion on BBC or McGraw-Hill website. Role play diffusion in and liquids at different temperatures and concentrations. Link to 4.1.1 of matter Apply particle model to diffusion. MS 4a, 4b, 4c, 4d Plot, draw and interpret appropriate graphs. diffusion. Observe slides or micrographs of villi, alveoli, root hair cells and leaves. two empty gas jars. Activity: McGraw-Hill Higher Education: 4.1.3.3 cont. may move across cell membranes by osmosis. Cell membranes are partially permeable: they allow small molecules such as water through but not larger molecules. During osmosis water diffuses from where it is more concentrated (because the solute concentration is lower), through a partially permeable Define the term ‘osmosis’. Explain how substances are transported into and out of cells through osmosis. 1 Set up a simple osmometer at the start of the lesson and measure how far the liquid in the capillary tube rises during the lesson. Explain the movement of water molecules as a special type of diffusion through a partially permeable membrane. Predict and explain what will happen to cellulose tubing bags filled with water or sugar Make predictions with explanations. Investigate the effect of water and concentrated salt solution on onion/ beetroot/ rhubarb cells. osmosis. Required practical 4: investigate the effect of a of concentrations of salt or sugar solutions Cellulose tubing filled with concentrated sugar solution attached to capillary tube held in clamp, beaker of water. Four beakers (two of water and two of sugar solution); four cellulose
membrane to where water is less concentrated (because the solute concentration is higher). solution, placed in beakers of water or sugar solution. Observe and explain the effects of water and concentrated salt solution on cells of onion/beetroot/rhubarb. Use a to show osmosis or get pupils to make a model. Watch a computer simulation of osmosis in plant and animal cells. Watch a video clip of osmosis in blood cells. Pupils research online 'osmotic power as a source of renewable energy'. Report to the class – define, describe, explain, evaluate. MS 4a, 4b, 4c, 4d Plot, draw and interpret appropriate graphs. MS 1c Calculate percentage gain and loss of mass. on the mass of plant tissue. Biology AT 1, 3 and 5 sausages (two of water and two of sugar solution). Observation activity materials: living plant cells: onion/beetroot/ rhubarb microscopes slides coverslips water concentrated solution pipettes blotting paper. Model materials: clear plastic box plasticine for membrane different balls for water and solute. Video clip:
4.1.3.3 cont. Some substances move across cell membranes via active transport. Active transport involves the movement of a dissolved substance from a region where it is less concentrated to a region where it is more concentrated. This requires energy from respiration. Active transport allows mineral ions to be absorbed into root hairs from very dilute solutions in the soil. It also allows sugar molecules to be absorbed from lower concentrations in the gut into the blood with a higher sugar concentration. Define the term ‘active transport’. Describe where active transport occurs in humans and plants and what is transported. Explain why active transport requires energy. Explain how active transport enables to absorb ions from very dilute solutions. Explain the relationship between active transport and oxygen supply and numbers of mitochondria in cells. 1 Recap diffusion and osmosis. Compare them with active transport. Produce a comparison table. What does the name 'active transport' tell you about the process? Pupils think of alternative, descriptive names for diffusion and osmosis. Introduce active transport as absorption against the concentration gradient. Discuss when this be useful. Pupils link the particle model and energy-transfer model to explain active transport. Pupils plan a 60 second presentation comparing and contrasting diffusion, osmosis and active transport. Research where active transport occurs in plants and Investigate the effect of oxygen availability on the growth of plants. Observe results in later lessons. Oxygen: gas jars with lids, glass tubes, fresh and boiled water to make mineral ion solution(s), black paper.
chromosomes in human body cells. DNA is in the chromosomes and each chromosome carries a large number of genes. Cells divide so that organisms can grow during the development of multicellular organisms, and repair damaged tissues. Dividing cells go through a series of stages called the cell cycle. During the cell cycle the genetic material doubles and then divides to give two new cells that are genetically identical to each other and to the original cell. Knowledge of the stages of the cell cycle and mitosis is not required. Before a cell can divide it must grow, and make copies of all the Draw simple diagrams to describe mitosis. Draw a simple diagram to describe the cell cycle in terms of: cell growth, when the number of organelles increases replication of chromosomes, so the genetic material is doubled separation of the chromosomes: division of the nucleus division of the cell to form two identical cells. Observe mitosis in cells. Role play the process of mitosis or use plasticine, pipe cleaners, beads etc to make a simple model. Draw simple diagrams to describe the cell and mitosis. Activity: What would happen if…? Eg: … DNA did not replicate? …. chromosomes did not line up down the middle? … organelles did not replicate? Observation activity materials: bioviewers microscopes slides coverslips root tips. Nuffield Foundation Investigating mitosis in allium root tip squash Animation:
Differentiation is essential to produce a variety of cells with different functions in multicellular organisms eg blood cells, nerve cells and muscle cells in animals, and root hair cells, xylem and phloem cells in plants. Cells that have become specialised cannot later change into different kinds of cells. However, there are some stem cells in most adult tissues that are ready to start dividing to replace old cells or to repair damage in the tissues where they are found. What am I? Describe the key features of different specialised cells – pupils guess the cell type. Watch a video clip showing cell differentiation in plants and animals. Video clip: BBC Bitesize – and animal cell structures Europe’s stem cell hub – Stem cell videos and films Wellcome Trust uses of stem cells BBC Bitesize – Stem cells
4.1.4 Waves Spec ref. Summary of the specification content Learning outcomes What most candidates should be able to do Suggested timing (hours) Opportunities to develop scientific communication skills Opportunities to apply practical and enquiry skills Self/peer assessment Opportunities and resources Reference to past questions that indicate success 4.1.4.1 In a transverse wave the oscillations are perpendicular to the direction of energy transfer. The ripples on a water surface are an example of a transverse wave. In a longitudinal wave the oscillations are parallel to the direction of energy transfer. Longitudinal waves show areas of compression and rarefaction. Sound waves travelling through air are longitudinal. Describe the difference between transverse and longitudinal waves. Describe how ripples on water surfaces are examples of transverse waves whilst sound waves in air are longitudinal waves, and how the speed of each may be measured. Describe evidence that in both cases it is the wave and not the water or air itself that travels. Describe how the speed of ripples on a water surface can be measured. Describe and explain how the speed of sound waves in air can be measured experimentally. 1 Draw diagrams to show the features of transverse and longitudinal waves. Give examples of both transverse and longitudinal waves. Describe the propagation of both transverse and longitudinal waves. Explain the changes in air pressure caused by longitudinal waves in regions of compression and rarefaction. List the waves in the electromagnetic spectrum in order of shortest to longest wavelength. What do waves look like? Do all waves have the same properties? Demonstrate how transverse and longitudinal waves travel using a slinky spring. Plan an experiment to measure the of sound in air. Eg bang two pieces of wood together facing a large wall and record the time taken to hear the echo. Measure the distance to the wall and double it. Required practical 5: make observations to identify the suitability of apparatus to measure the frequency, wavelength and speed of waves in a ripple tank and waves in a solid and take appropriate
measurements. Physics AT 4. If a ripple tank isn’t available then the following two from are available. Activities listed on Institute of Physics website Demonstrate a fluid (corn starch) on a speaker cone or 4.1.4.2 Waves are described by their amplitude, wavelength, frequency and period. The amplitude of a wave is the maximum displacement of a point on a wave away from its undisturbed position. The wavelength of a wave is the distance from a on one Define: wavelength amplitude frequency peak trough period. Calculate the wavelength of a wave. Calculate the frequency of a wave the number of waves and the time. 1 Calculate the wavelength of a wave from a labelled diagram of a wave. Calculate the frequency of a wave given the number of waves (possibly from interpreting a diagram) and the time. Calculate the speed of a wave. Rearrange the equation to find any unknown given the other two values. What do waves do? What effect does increasing the amplitude/frequency of a sound wave have? Demonstrate the above using a loudspeaker and signal generator connected to an oscilloscope. Vary the frequency and then the amplitude on the signal
wave to the equivalent point on the adjacent wave. The frequency of a wave is the number of waves passing a point each second. period, T, in seconds, s frequency, f, in Hertz, Hz The period of a wave is how long it takes for one wave to pass a point. The wave speed is the speed at which the energy is transferred (or the wave moves) through the medium. All obey the wave equation: Calculate the speed of a wave. Rearrange the equation to find any unknown given the other two values. generator – what is observed? Demonstrate that changing the frequency of a transverse wave on a length of rope changes the wavelength. Pupils could investigate how to accurately measure the period of a wave, ie time a fixed number, say 10 and then divide the time by this number. MS 1a, 1c, 3b, 3c Recall and apply the wave equation. MS 1b, 2a Complete calculations using standard form and give answers to an appropriate number of significant figures.
reflect waves. Rough surfaces scatter waves in all directions. Electromagnetic waves change speed when they travel between different substances such as from air to glass or water. As a result they change direction. This is refraction. how some effects are related to differences in the velocity of the waves in different substances. wave at the boundary between two different media. WS 1.2 Use wavefront diagrams to explain refraction in of the change of wave speed. Demonstration of the properties of microwaves using a microwave transmitter and a detector connected to a If you have a ripple tank you can demonstrate refraction as waves go into different depths of water, or use this video on