p3 – radioactive materials
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P3 – Radioactive Materials. Radioactive Elements. Some elements emit ionising radiation all the time and are called radioactive Radioactive elements are naturally found in the environment, emitting background radiation . The Atom. - PowerPoint PPT PresentationTRANSCRIPT
P3 – Radioactive Materials
Radioactive Elements• Some elements emit ionising radiation all the time
and are called radioactive • Radioactive elements are naturally found in the
environment, emitting background radiation
The Atom• Electrons, Protons, Neutrons and the Nucleus
are all parts of an atom• The Nucleus, made of Protons and Neutrons
Isotopes• Every atom of any element has the same number
of protons but the number of neutrons may differ• The same element with different numbers of
neutrons is called an isotope• These 3 atoms are all isotopes of Hydrogen:
The Nucleus is the only thing involved in Radioactive Substances• Radioactive Materials are unchanged by:– Chemical reactions (only electrons involved in these)– Changes of state (Solid, Liquid, Gas)– Crushing
3 Types of Radiation
• Alpha: – 2 Protons + 2
Neutrons
• Beta:– 1 Electron
• Gamma:– High energy wave
An unstable nucleus will emit radiation to become more a more stable nucleus
Half-Life• Overtime, the
Activity of Radioactive Sources Decrease
• Half-Life: The time it takes for the number of unstable atoms in a sample to halve.
• Carry out simple calculations
Ionising Radiation• Ionising Radiation removes electrons from
atoms creating Ions (Charged atoms). These can then take part in other chemical reactions
When ionising radiation strikes living cells these may be
killed or may become cancerous
Helpful Ionising Radiation• Ionising Radiation can be used to: – sterilise surgical instruments– sterilise food– treat cancer
Electricity• Electricity is a secondary energy source. • This means that we get electricity from the
conversion of other sources of energy, such as coal, nuclear, wind or solar energy.
• These are called primary sources.
Electricity = Convenient• Electricity is convenient because it is easily
transmitted over distances and can be used in many ways
Making Electricity1. Coal is burnt to heat water to make steam2. The steam turns the turbine3. Turbine turns a generator which produces electricity4. Electricity goes to the transformers to produce the
correct voltage
Efficiency• Light bulbs are only 10% efficient. 90% of the
energy provided to them is lost as heat
You need to know how to read these diagrams
Renewable Energy• Recall two examples:
1. Solar panels2. Wind turbines3. Geothermal4. Hydroelectricity
Power stations which burn carbon fuels (fossil fuels) produce carbon dioxide
Nuclear Fuel / Nuclear Fission• Changes in the nucleus creates lots of energy• Nuclear Fission: a neutron splits a large and
unstable nucleus (Uranium) into two smaller parts, roughly equal in size, releasing more neutrons
Nuclear Energy• The amount of energy contained in nuclear fuel is
millions of times the amount of energy contained in a similar mass of chemical fuel such as coal, making nuclear fission a very tempting source of energy.
• Nuclear Fission creates a chain reaction and these can be dangerous unless they are controlled
Controlling Fission
• Fission heats the coolant which is used for steam
• Control rods absorb neutrons
• These can be moved up and down to control the amount of neutrons escaping the fuel rods
Radioactive Waste• Is categorised into 3 parts and this relates to it’s
disposal methods– high – intermediate – low