Companion PDF worksheet for Edexcel IGCSE Biology Lecture 55 - Pollution and Global Warming. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.12 -Understand the biological consequences of pollution of air by sulfur dioxide and carbon monoxide. Specification Point 4.13 - Understand that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases. Specification Point 4.14 - Understand how human activities contribute to greenhouse gases. Specification Point 4.15- Understand how an increase in greenhouse gases results in an enhanced greenhouse effect and that this may lead to global warming and its consequences. Specification Point 4.16 - Understand the biological consequences of pollution of water by sewage. Specification Point 4.17 - Understand the biological consequences of eutrophication caused by leached minerals from fertilizer. Complete set of Chapter 6 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 56 - Deforestation. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.18B - Understand the effects of deforestation, including leaching, soil erosion, disturbance of evapotranspiration and the carbon cycle, and the balance of atmospheric gases. Complete set of Chapter 6 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 54 - The Nitrogen Cycle. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.11B - Describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria. Complete set of Chapter 6 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 52 - Feeding Relationships. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.6 - Understand the names given to different trophic levels, including producers, primary, secondary and tertiary consumers and decomposers. Specification Point 4.7 - Understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer. Specification Point 4.8 - Understand the transfer of substances and energy along a food chain. Specification Point 4.9 - Understand why only about 10% of energy is transferred from one trophic level to the next. Complete set of Chapter 6 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 53 - The Carbon Cycle. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.10 - Describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion. Complete set of Chapter 6 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 51 - Biotic and Abiotic Factors. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.5 - Understand how abiotic and biotic factors affect the population size and distribution of organism. Complete set of Chapter 6 Worksheets are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.2.1 - Understand the main types of business ownership. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.1.2 - Understand why business aims and objectives change as businesses evolve. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.44 - Describe tests for these gases: hydrogen, oxygen, carbon dioxide, ammonia and chlorine. Specification Point 2.45 - Describe how to carry out a flame test. Specification Point 2.46 - Know the colours formed in flame tests for the following cations: lithium, sodium, potassium, calcium and copper. Specification Point 2.47 - Describe tests for these cations: ammonium using sodium hydroxide solution and identifying the gas evolved. Copper, iron (II) and iron (III) using sodium hydroxide solution. Specification Point 2.48 - Describe tests for these anions: chloride, bromide and iodide using acidified silver nitrate solution. Sulphates using acidified barium chloride solution and carbonates using hydrochloric acid and identifying the gas evolved. Specification Point 2.49 - Describe a test for the presence of water using anhydrous copper (II) sulphate. Specification Point 2.50 - Describe a physical test to show whether a sample of water is pure. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.14 - Know that light waves are transverse waves and that they can be reflected and refracted. Specification Point 3.15 - Use the law of reflection. Specification Point 3.16 - Draw ray diagrams to illustrate reflection and refraction. Specification Point 3.17 - Practical: investigate the refraction of light, using rectangular blocks, semi-circular blocks and triangular prisms. Specification Point 3.18 - Know and use the relationship between refractive index, angle of incidence and angle of refraction. Specification Point 3.19 - Practical: investigate the refractive index of glass, using a glass block. Specification Point 3.20 - Describe the role of total internal reflection in transmitting information along optical fibres and in prisms. Specification Point 3.21 - Explain the meaning of critical angle c. Specification Point 3.22 - Know and use the relationship between critical angle and refractive index. Specification Point 3.23 - Know that sound waves are longitudinal waves which can be reflected and refracted. Complete set of Chapter 3 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.25 - Know and use the relationship between momentum, mass and velocity. Specification Point 1.26 - Use the idea of momentum to explain safety features. Specification Point 1.27 - Use the conservation of momentum to calculate the mass, velocity or momentum of objects. Specification Point 1.28 - Use the relationship between force, change in momentum and time taken. Specification Point 1.29 - Demonstrate an understanding of Newton’s third law. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.37 - Understand how ions are formed by electron loss or gain. Specification Point 1.38 - Know the charges of several atomic and molecular ions. Specification Point 1.39 - Write formulae for compounds formed between the ions listed in 1.38. Specification Point 1.40 - Draw dot-and-cross diagrams to show the formation of ionic compounds by electron transfer, limited to combinations of elements from groups 1, 2, 3, 5, 6 and 7. Specification Point 1.41 - Understand ionic bonding in terms of electrostatic attractions. Specification Point 1.42 - Understand why compounds with giant ionic lattices have high melting and boiling points. Specification Point 1.43 - Know that ionic compounds do not conduct electricity when solid, but do conduct electricity when molten and in aqueous solution. Complete set of Chapter 3 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.6 - Know and use the relationship between acceleration, change in velocity and time taken. Specification Point 1.7 - Plot and explain velocity-time graphs. Specification Point 1.8 - Determine acceleration from the gradient of a velocity−time graph. Specification Point 1.9 - Determine the distance travelled from the area between a velocity-time graph and the time axis. Specification Point 1.10 - Use the relationship between final speed, initial speed, acceleration and distance moved. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 9.3 - Understand the range of international strategies (international aid and intergovernmental agreements) that attempt to reduce uneven development. Specification Point 9.3 - Understand the different views held by individuals, organisations and governments on tackling the development gap. Complete set of Chapter 10 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 8.2 - Understand the impacts of globalisation on different groups of people, including the benefits and costs to countries hosting TNCs. Specification Point 8.2 - Understand the impacts of migration (voluntary, forced, national, international and rural-urban) on different groups of people. Complete set of Chapter 9 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 8.1 - Understand the push and pull factors that have influenced rates of different types of migration over the last 50 years. Complete set of Chapter 9 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 9.1 - Understand that different factors contribute to the development and human welfare of a country: economic, social, technological, cultural, as well as food and water security. Specification Point 9.1 - Understand that development is measured in different ways: GDP per capita, the Human Development Index, measures of inequality and indices of political corruption. Complete set of Chapter 10 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 9.3 - Understand the advantages and disadvantages of top-down and bottom-up development projects used to promote development in a named developed and a named emerging or developing country. Complete set of Chapter 10 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 9.2 - Understand the global pattern of the uneven development between and within countries and the factors (social, historic and economic) that have led to these spatial variations. Specification Point 9.2 -Understand the impact of uneven development on welfare and quality of life within one named country. Complete set of Chapter 10 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 7.3 - Understand how technology can resolve water-resource shortages in fragile environments under threat from desertification. Specification Point 7.3 - Understand the different approaches to the sustainable use and management of a rainforest in a named region to limit the extent of deforestation. Complete set of Chapter 8 Lectures are available.