Module P1- Energy for the home(Part 1)
- Created by: Kimberley
- Created on: 16-04-14 10:48
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- Module P1- Energy for the home(Part 1)
- Moving and Storing Heat
- Heat
- Measure of energy
- Temperature
- Measure of the average kinetic energy of the particles in a substance.
- Measured in °C
- Specific Heat Capacity
- The amount of energy needed to raise the temperature of 1kg of a substance by 1°C.
- Energy(j)= Mass(kg) x Specific Heat Capacity(j/kg/°C) x Temperature Change(°C)
- Energy flows from hot objects to cooler ones
- If there's a difference in temperature between two places, then energy will flow between them.
- Heat
- Melting and Boiling
- Boiling
- When you heat a liquid, the heat energy makes the particles move faster.
- Eventually, when enough of the particles have enough energy to overcome their attraction to each other, big bubbles of gas form in the liquid.
- When you heat a liquid, the heat energy makes the particles move faster.
- Melting
- Heat energy makes the particles vibrate faster until eventually the forces between them are overcome and the particles start to move around.
- When a substance is melting or boiling, the energy is used for breaking intermolecular bonds rather than raising the temperature.
- When a substance is condensing or freezing, bonds are forming between particles, which release energy.
- Temperature won't go down.
- Specific Latent Heat
- The amount of energy needed to change state
- Energy(j) = Mass(kg) x Specific Latent Heat( j/kg)
- Boiling
- Conduction
- Occurs mainly in Solids
- The process where vibrating particles pass on extra kinetic energy to neighboring particles
- Metals are good conductors
- Electrons move faster and collide with other free electrons, transferring energy inside the metal.
- Convection
- Occurs in Liquids and gases
- The more energetic particles move from the hotter region to the cooler region and take their heat energy with them.
- When you heat up a liquid or a gas, the particles move faster and expand to become less dense.
- The warmer air rises above the cooler air
- This process forms convection currents
- The warmer air rises above the cooler air
- Heat Radiation
- All objects emit and absorb heat radiation
- Cooler objects absorb the heat radiation emitted by hotter objects
- Temperature increases
- Dark Matt surfaces
- Good absorbers and emitters of infrared radiation
- Light coloured smooth and shiny objects
- Poor absorbers and emitters of infrared radiation
- Reflect heat radiation
- Poor absorbers and emitters of infrared radiation
- It can travel in a vacuum
- Heat reaches us from the sun
- Saving Energy
- Insulation
- Loft Insulation
- Fiberglass wool laid across the loft floor reduces conduction
- Hot Water Tank Jacket
- Reduces Conduction
- Double Glazing
- Two layers of glass with an air gap between reduce conduction
- Cavity Walls
- Twolayers of bricks with a gap between them reduce conduction
- Insulation foam in the gap traps pockets of air to minimize convection.
- Draught- proofing
- Strips of foam and plastic around doors and windows stop hot air from escaping and reduces convection.
- Thick Curtains
- Reduce conduction and radiation through the window
- Loft Insulation
- Sources
- Emit energy
- E.g radiators
- Sinks
- Lose energy
- E.g windows and computers
- Payback Time= Initial Cost / Annual Saving
- Thermograms
- Shows where you are wasting energy in different areas.
- White, yellow and red
- Losing energy
- Black, dark blue and purple
- Not losing energy
- White, yellow and red
- Shows where you are wasting energy in different areas.
- Insulation
- Efficiency
- Efficiency=(Useful Energy Output/ Total Energy Input) x 100%
- Wave Basics
- Amplitude is the displacement from the rest position to the crest
- The wavelength is the length of a full cycle of the wave
- Frequency is the number of complete cycles.
- Measured in hertz(Hz)
- Reflection
- Angle of Incidence= Angle of Reflection
- Total Internal reflection
- Angle of incidence is greater than the critical angle
- When the ray of light enters a less dense medium it will bend away from the normal
- Diffraction
- Waves spread out when they pass through a gap or pass an object
- The narrower the gap, the more the wave spreads out.
- Refraction
- When a ray of light enters a more dense medium it will bend towards the normal
- When a ray of light enters a less dense medium it will bend away from the normal
- Moving and Storing Heat
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