Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.7 - Explain why a series or parallel circuit is more appropriate for particular applications, including domestic lighting. Specification Point 2.8 - Understand how the current in a series circuit depends on the applied voltage and the number and nature of other components. Specification Point 2.9 - Describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how to investigate this experimentally. Specification Point 2.10 - Describe the qualitative effect of changing resistance on the current in a circuit. Specification Point 2.11 - Describe the qualitative variation of resistance of light-dependent resistors (LDRs) with illumination and thermistors with temperature. Specification Point 2.12 - Know that lamps and LEDs can be used to indicate the presence of a current in a circuit. Specification Point 2.13 - Know and use the relationship between voltage, current and resistance. Complete set of Chapter 2 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.22 - Understand that most phenotypic features are the result of polygenic inheritance rather than single genes. Specification Point 3.23 - Describe patterns of monohybrid inheritance using a genetic diagram. Specification Point 3.24 - Understand how to interpret family pedigrees. Specification Point 3.25 - Predict probabilities of outcomes from monohybrid crosses. Specification Point 3.26 - Understand how the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male. Specification Point 3.27 - Describe the determination of the sex of offspring at fertilisation, using a genetic diagram. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.5C - Know what is meant by the term solubility in the units grams per 100 grams of solvent. Specification Point 1.6C - Understand how to plot and interpret solubility curves. Specification Point 1.7C - Practical: investigate the solubility of a solid in water at a specific temperature. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.1.8.1 - Born-Haber cycles. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.1.10 - The equilibrium constant, Kp for homogeneous systems. Complete set of Chapter 6 Lectures are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 37 - Reproduction in Plants. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 3.3 - Describe the structures of an insect-pollinated and a wind-pollinated flower and explain how each is adapted for pollination. Specification Point 3.4 - Understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation. Specification Point 3.5 - Practical: investigate the conditions needed for seed germination. Specification Point 3.6 - Understand how germinating seeds utilise food reserves until the seedling can carry out photosynthesis. Specification Point 3.7 - Understand that plants can reproduce asexually by natural methods (illustrated by runners) and by artificial methods (illustrated by cuttings). Complete set of Chapter 5 Worksheets are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 9.2 - Understand how countries at different levels of development have differences in their demographic data. Complete set of Chapter 10 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 1.22 - Practical: investigate how extension varies with applied force for helical springs, metal wires and rubber bands. Specification Point 1.23 - Know that the initial linear region of a force-extension graph is associated with Hooke’s law. Specification Point 1.24 - Describe elastic behaviour as the ability of a material to recover its original shape after the forces causing deformation have been removed. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.3.4.1 - Structure, bonding and reactivity of alkenes. Specification Point 3.3.4.2 - Addition reactions of alkenes. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.8.2.2 - Regulation of transcription and translation. Complete set of Chapter 8 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.1.1 - Social influence. Types of conformity: internalisation, identification and compliance. Explanations for conformity: informational social influence and normative social influence. Variables affecting conformity including group size, unanimity and task difficulty as investigated by Asch. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.7.4 - Populations in ecosystems. Complete set of Chapter 7 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.3.4.1 - Mass transport in animals. Complete set of Chapter 3 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.24 - Understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre. Specification Point 2.25 - Identify the sources and describe the functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, the mineral ions calcium and iron, water and dietary fibre as components of the diet. Specification Point 2.26 - Understand how energy requirements vary with activity levels, age and pregnancy. Complete set of Chapter 2 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.1 - Understand the terms population, community, habitat and ecosystem. Specification Point 4.2 - Practical: investigate the population size of an organism in two different areas using quadrats. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 8.2 - Know that the universe is a large collection of billions of galaxies, that a galaxy is a large collection of billions of stars and that our solar system is in the Milky Way galaxy. Specification Point 8.3 - Understand why gravitational field strength, g, varies and know that it is different on other planets and the Moon from that on the Earth. Specification Point 8.4 - Explain that gravitational force causes moons to orbit planets, causes the planets to orbit the Sun, causes artificial satellites to orbit the Earth and causes comets to orbit the Sun. Specification Point 8.5 - Describe the differences in the orbits of comets, moons and planets. Specification Point 8.6 - Use the relationship between orbital speed, orbital radius and time period. Complete set of Chapter 8 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.7.1 - Inheritance. Complete set of Chapter 7 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.1.5.1 - Collision theory. Specification Point 3.1.5.2 - Maxwell-Boltzmann distributions. Specification Point 3.1.5.3 - Effect of temperature on reaction rate. Specification Point 3.1.5.4 - Effect of concentration and pressure on reaction rate. Specification Point 3.1.5.5 - Catalysts. Practical 3: Investigation of how the rate of a reaction changes with temperature. Complete set of Chapter 3 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.3.1 - Introduction to organic chemistry. Specification Point 3.3.1.1 - Nomenclature. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.5.2 - Respiration. Complete set of Chapter 5 Lectures are available.