Nuclear Fusion Ernest Rutherford In 1909, Ernest Rutherford, Hans Geiger and Ernest Marsden tried firing positively charged alpha particles at thin foil. Most of these particles just went straight through but the odd one came straight back at them. This meant: Most of...
Radioactivity Atoms Atoms consist of a nucleus and orbiting electrons. The nucleus of an atom contains protons and neutrons. It makes up most of the mass of the atom, but takes up virtually no space. The electrons that orbit the atom are really small. They whizz...
Sun = star à scientists analyse surface +radiation Hotter areas of sun = white Warmer areas = orange Spectrum shows the elements that are present in the sun. Coronal mass ejection – bubbles of gas bursting out of the sun and...
How far away are the stars? 3A Parallax- The apparent change in something’s position based on line of sight Stars seem to shift their positions slightly against a background of fixed stars. The...
Brief intro The shadows of the moon are sometimes smooth or rough- this was due to mountainsàchallenged views of perfect and unchanging heavens. Use telescopes to study electromagnetic from distant objectsàdata collected led to new discoveries Optical telescopes use...
Topic 1: Naked eye astronomy Astrolabe – measures the angle of a star above the horizon. Used for navigation. Eclipse – the sun moves behind the moon (allows you to observe gasses in the corona) The sun rises at the east and sets in the west, at a steady speed....
P4 – Explaining motion P4.1 How can we describe motion? The speed of a moving object can be calculated if the distance travelled and the time taken is known. Speed is just the travelled distance in a certain time When an object moves in a straight line at a steady...
P3.1 How much energy do we use? The global demand for energy is continually increasing. Our population is growing – we already have more people on the planet than ever before. As well as this, modern lifestyles demand transport and communications technology – which...
P3.2 How can electricity be generated? Electricity is a SECONDARY ENERGY SOURCE because we use primary sources to produce it – these primary sources can be non-renewable or renewable. Electricity is convenient because: It is transmitted easily over distance, through...
P3.3 Which energy sources should we choose? Ways to save energy In the home In the workplace National context ● More efficient appliances, e.g. a condensing boiler could save £190 per year ● Double glazing – possible savings of £130 per year ● Loft insulation –...
P2.4 How are electromagnetic waves used in communications? Different electromagnetic eaves have different frequencies. This affects their properties and the effect that other materials have on them. Some frequencies can be used for transmitting information:...
P2.2 Which types of electromagnetic radiation harm living tissue and why? When living cells absorb radiation, damage can occur in different ways: The heating effect can cause damage Ionising radiation, such as ultraviolet radiation, can damage cells, causing ageing of...
P2.3 What is the evidence for global warming, why might it be occurring, and how serious a threat it is? The sun emits electromagnetic radiation with a principle frequency that increases with temperature – the Earth is surrounded by an atmosphere that allows some of...
P1.1 What do we know about the place of the Earth in the Universe? The Earth is one of eight planets orbiting the sun in almost circular paths, together with other smaller objects including asteroids, dwarf planets, comets and moons. The solar system is made. The...
P1.2 What do we know about the Earth and how it is changing? Rocks provide evidence for changes in the Earth: Erosion – the Earth’s surface is made up of LAYERS of rock, one on top of the other with the oldest at the bottom. The layers are made of compacted SEDIMENT,...