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Hint
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Answer
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Thermal ___ RP
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Insulation
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Aim: to measure the rate of ___ of a beaker of hot water when insulated with different materials and different thicknesses of the same material
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Cooling
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Thickness: Wrap 2 beakers in ___ thicknesses of the same insulating material
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Different
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Put the same ___ of hot water in each beaker
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Volume
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Use a piece of cardboard for the lid with a hole for the ___
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Thermometer
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Record the temperature of the water every ___ minutes for 30 minutes
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3
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The ___ the thickness, the lower the rate at which the hot water cools
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Greater
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Different Materials: Place some insulating material around the ___ of a beaker
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Inside
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Place a ___ beaker inside the insulation and pour hot water into it
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Smaller
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Then follow the same method as thickness from step ___ onwards. Repeat with differing insulating materials
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2
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The ___ the thermal conductivity, the lower the rate at which the water cools
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Higher
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___ ___ occurs when electrical charges are transferred onto/off the surface of an insulator
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Static electricity
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This makes the insulator gain a ___
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Charge
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They become ___ charged when electrons move onto the insulator from a cloth due to friction
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Negative
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Eg. when ___ is rubbed with a cloth
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Polythene
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They become ___ charged when electrons move off the insulator and onto the cloth due to friction
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Positively
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Eg. when ___ is rubbed with a cloth
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Acetate
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An ___ ___ is a region in space where a charged particle may experience a force
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Electrical field
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Electric field from a positively charged point: acts ___ ___
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Radially outwards
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Electric field from a negatively charged point: acts ___ ___
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Radially inwards
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Electric field strength is a ___ quantity
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Vector
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Positive charges attract ___ charges
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Negative
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The strength of the field is shown by the ___ of the field lines. The greater this is, the stronger the field.
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Concentration
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Low levels of radiation are around all the time, either natural or man-made. Called ___ ___
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Background radiation
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For example ___ is a radioactive gas produced when uranium in rock decays
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Radon
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It's particularly prominent in ___
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Cornwall
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Radiation dose is measured in ___ (Sv)
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Sieverts
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A dose of ___Sv will lead to death but a human only experiences around 0.000003Sv an hour
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0.1
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To identify a problem with a thyroid gland, a patient can drink a solution of ___ ___
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Radioactive iodine
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This organ works by absorbing iodine and using it to make ___
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Hormones
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The iodine emits ___ radiation that passes out of the body and can be detected. If too much or too little iodine has been absorbed, the doctor can use this to diagnose the condition
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Gamma
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Radioactive ___ can also be used for bone scans, for example to see the damage caused by arthritis or to detect tumours
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Tracers
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The tracer must emit radiation that can ___ ___ of the body and be detected
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Pass out
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It must not be ___ ___ to minimise damage to body tissue
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Strongly ionising
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It must not decay into another ___ ___
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Radioactive isotope
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It must have a short ___ ___ so it is not present in the body for a long period
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Half life
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Certain cancers can be destroyed using ionising radiation - ___
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Radiotherapy
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Gamma rays pass into the body from outside and ___ the tumour
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Destroy
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However, ___ ___ may also be damaged as the radiation passes through the body
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Healthy tissues
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You can also have radiation sources placed inside the body - eg. ___ ___ to treat prostate cancer
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Radioactive rods
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This is targeted very ___ to the tumour, causing less damage to healthy tissue
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Precisely
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In a nuclear fission reaction, a large, ___ nucleus splits into 2 smaller ones
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Unstable
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For example, a ___nucleus splits when it absorbs a neutron
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Uranium-235
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This produces 2 radioactive ___ nuclei that are roughly the same size
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Daughter
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It also releases 2+ neutrons and ___
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Energy
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These neutrons may be absorbed by other nuclei, which undergo fission and produce more neutrons: a ___ ___
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Chain reaction
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if this is not controlled there will be a ___ ___
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Nuclear explosion
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Nuclear ___ make use of controlled chain reactions
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Reactors
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Nuclear ___ is the joining of smaller nuclei to form larger nuclei
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Fusion
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During the stable period of a star's life, vast quantities of hydrogen nuclei are converted to ___ nuclei by this
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Hydrogen
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The mass of the reactants is slightly ___ than that of the products.
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More
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The mass difference is released as ___ ___
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Thermal energy
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Nuclei need to get very ___ before fusion can happen
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Close
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Under normal conditions, the positive charges on nuclei ___ each other: electrostatic repulsion
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Repel
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High temperatures and pressures are required to allow the nuclei to move ___ enough to overcome the electrostatic repulsion
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Fast
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All experimental reactors so far have used ___ energy than they have produced to provide these conditions
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More
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Gas pressure depends on the ___ of particles in the gas
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Motion
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The particles strike the walls of the container at many different angles, so the pressure of the gas is the net force at ___ ___ to the wall
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Right angles
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Pressure can be increased by ___ the mass of a gas
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Increasing
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Pressure can be increased by ___ the temperature of a gas
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Increasing
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Pressure can be increased by ___ the volume of a gas
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Decreasing
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This is because that makes the gas particles hit the wall with a higher ___ so more force is exerted per unit volume
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Frequency
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This is either because the gas takes up more space within the region, or due to an increase in ___ ___
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Kinetic energy
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The change of a volume in a gas is ___ proportional to the change in pressure when the mass and temperature are constant
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Inversely
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Pressure (Pa) x Volume = ___
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Constant
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When a gas is ___ quickly its volume decreases quickly
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Compressed
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Its temperature can rise because ___ is being done in compressing the gas so kinetic energy of the particles increases
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Work
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