NS Exam 30 Nov Flashcards
When does heat transfer happen
The transfer only occurs if there is a temperature difference.
Name 2 things that insulating materials do
1) Help minimize heat loss in winter and heat gain in summer
2) They slow down heat loss or heat gain through convection, conduction, and radiation.
Name 2 insulating materials
Fabrics
Styrofoam
How do fabrics insulate
The woven fibers of the fabric trap air between them. Air is a poor conductor of heat and so it slows heat loss through the fabric.
How does styrofoam insulate
It is made from polystyrene which has had air pumped through it. This makes styrofoam extremely light and the air pockets make it a very good insulator.
Internal temperature is much higher than the surroundings, heat moves from our bodies to the environment
What is this called
Heat loss
What is the main source of heat energy on Earth
The main source of heat energy = radiation from the sun
Name 3 ways to save energy at home
1) Turn off unnecessary lights.
2) Change your light bulbs to energy-efficient bulbs.
3) Use a geyser blanket.
4) Unplug unused electronics.
5) Use extra blankets instead of a heater.
6) Turn the geyser off when you leave the house.
7) Only do full loads of washing or dishes.
8) Wash clothes with cold water.
How do solar water heating systems work
Hot water can be used directly or the steam can be used to turn turbines to generate electricity
Coldwater flows in the cold water intake pipe and then down the long tubes, called evacuated tubes. The water warms up due to energy transfer from the Sun and it then flows into the storage tank at the top. When someone wants hot water in the house, the hot water flows out of the hot water output and down into the house.
The water runs down the central heat pipe. There is an absorber plate below each pipe and this is enclosed within two layers of tube.
Between these tubes, there is a vacuum. This means that the Sun’s energy can still pass through to warm the water. However, when the energy is transferred to the water, and it warms up, the vacuum prevents energy from transferring back out by conduction or convection.
Underneath the heat pipe, there is a plate that helps to absorb radiant energy from the Sun and transfer it to the heat pipe
What is The energy which is transferred to the surroundings?
This energy is reffered to as wasted
What does a Sankey diagram do
Sankey diagram to show how the energy is transferred in a system
What are the 2main things in a Sankey diagram and where do they go
useful energy (arrow at the top) and wasted energy (arrow going to the bottom)
What is the input energy made up of
The width of both the output energy arrows (useful and wasted) add up to the width of the input arrow.
True or false
Sankey diagrams are drawn to scale
True
An efficient system is one where the useful output energy is only slightly (bigger/smaller) than the input energy
smaller
An inefficient system has a lot of wasted energy.
What is the formula for energy efficiency
Energy Efficiency = Useful Output energy
~~~~~~~~~~~~~~~~~~~~
Total input Energy
AT what % efficiency is the most efficient coal power station
The most efficient coal-fired power plants only operate at around 44% efficiency
When large chunks of coal are crushed into a fine powder. What is it called
This is called pulverization.
How is coal turned into electricity
The large chunks of coal are first crushed into a fine powder. This is called pulverisation.
The coal is then transported to a furnace where it is burnt.
Chemical potential energy ———> Thermal energy
The thermal energy from the burning coal is used to boil water and generate steam which is pressurised in the pipes
Thermal energy ———–> Kinetic energy
The steam pushes the blades of the turbine and so the turbine spins.
Kinetic energy ————-> Mechanical energy
Mechanical movement energy transfers from the turbine to the generator (rod/shaft)
The turbine is connected to the shaft of the generator which then rotates large magnets within wire coils, which generates electricity.
Mechanical energy ———-> Electrical energy
How does a generator work
A generator consists of a very large solenoid with a large rotating magnet. The solenoid is made up of thousands of coils of conducting wire. When the magnet is turned inside the coil, the generator produces electricity.
When is energy lost in a coal power station
The cooling tower where steam is lost.
Energy is also lost through the different energy transformations.
How does hydropower work
Falling water Turbines turning
Kinetic energy ——————-> Mechanical energy
Turbines turning the shaft which turns the generator
Mechanical energy ————>
Generator produces electricity
Electrical energy
How does wind make electricity
Exact same as hydropower but with wind as the kinetic energy
What are the Main Functions of the Sun relative to Earth
The Sun’s energy sustains life on Earth
Plants and animals depend on the Sun for warmth
The water cycle is dependent on the Sun’s energy
Stored energy from the Sun acts as a fuel
How does the sun sustain all life on Earth
Plants and animals get the energy they need to live from the sun.
Their life processes depend on this energy.
How Plants and animals depend on the sun for warmth
Energy from the Sun travels by electromagnetic waves and is absorbed by gases in the atmosphere and by Earth’s surface. The absorption of energy warms Earth’s water, air, and land.
How does The water cycle depends on energy from the Sun
The Sun’s heat energy drives the water cycle
Without the Sun’s heat energy, water would not evaporate and all water on Earth would freeze.
How are fossil fuels made
The remains of plants and animals are deposited under water, in swamps on land along the coast. They begin to decay.
Soil and mud are washed into the water. They form layers on top of the plants and animal remains. These layers of soil and mud press down on the remains.
More layers lead to increased pressure; the increased pressure, over a very long time, changes the remains into coal, oil and gas.
What are the 7 layers of the sun
inner layers are the
core, the radiative zone
and the convection zone,
while the outer layers are
the photosphere, the chromosphere,
the transition region and the
corona.
What are the qualities of the core of the sun
The innermost or central layer of the Sun. The core is plasma but moves similarly to a gas. In the core, nuclear reactions combine hydrogen atoms to form helium
What are the qualities of The radiative zone
The radiative zone is just outside the core. The energy released in the core travels extremely slowly through the radiative zone. Particles of light called photons can only travel a few millimeters before they hit another particle in the Sun, are absorbed and then released again.
What are the qualities of The convection zone
In the convection zone, hot material from near the Sun’s center rises, cools at the surface, and then plunges back downward to receive more heat from the radiative zone. This movement helps to create solar flares and sunspots.
What is the photospher and what does it do
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The photosphere is the visible surface of the Sun. It emits sunlight. It’s also one of the coolest layers of the Sun.
What is the chromosphere
The chromosphere is a thin region of the Sun’s atmosphere that glows red
What is the corona
The corona is the outermost layer
If you ever have the chance to see a total solar eclipse, you will be able to see the Sun’s corona, shining out into space.
What are sunspots
Sunspots: are cooler, darker areas on the Sun’s surface.If a loop of the sun’s magnetic field snaps and breaks, it creates solar flares
What are solar prominences
solar prominences: if plasma flows along a loop of the Sun’s magnetic field
Very important
Look at the three pictures of the sun
remember the lines of lat and longitude as well as any other details
You should be able to draw a diagram from scratch
What are the lines of latitude
North Pole 90° N (top)
Arctic Circle 66.5° N
Tropic of Cancer 23.5°N
Equator 0° degrees (middle)
Tropic of Capricorn 23.5°S
Antarctic Circle 66.5° S
South Pole 90° S (bottom)
What happens at 66 1/2 degrees depending on the season
At 66 ½ degrees North and South the entire line is either completely in the light or completely in the dark.
