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
```
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.
True or false
The position of the Earth relevant to the sun determines the season
True
The position of the Earth relevant to the sun determines the season
What seasons happen in December
Northern vs Southern hemisphere
In December
The southern hemisphere is tilted towards the Sun (Summer)
The northern hemisphere is tilted away from the Sun (Winter)
What seasons happen in June
The southern hemisphere is tilted away from the Sun (Winter)
The northern hemisphere is tilted toward it (Summer)
What happens to the seasons in March and September
In March and September
Neither hemisphere is tilted toward or away from the Sun
What is the intensity of solar energy equal to
The intensity of solar energy = amount of solar energy per unit area that reaches a place
What happens when a hemisphere is tilted towards the sun
Hemisphere tilted towards the Sun = more direct Sun rays = more intensity for a smaller area = summer
What happens when a hemisphere is tilted away from the sun
Hemisphere tilted away from the Sun = Suns ray reaches it at a smaller angle = larger area = less intensity = winter
What is the difference between direct rays and oblique rays
The same amount of energy is spread over a smaller area where the rays strike the Earth directly compared to obliquely.
Direct = over a short distance and smaller area of sunlight Oblique = over a long distance and larger area of sunlight
What is an equinox
These are the days when the Sun is exactly above the Equator, which makes day and night of equal length.
When do equinoxes happen
The equinoxes happen in March (about March 21) and September (about September 23).
What is a solstice
These are the days when the Sun’s path in the sky is the farthest north or south from the Equator.
When do the two solstices happen
The two solstices happen in June (20 or 21) and December (21 or 22).
A hemisphere’s winter solstice is the shortest day of the year and its summer solstice the year’s longest.
What is a solar eclipse
Look at diagram
A total solar eclipse occurs when the Earth, Moon and Sun are aligned in a straight line with the Moon placed in between the Earth and the Sun.
What is a lunar eclipse
Look at diagram
In a Lunar eclipse the Earth blocks the sunlight from reaching the Moon’s surface, making the Moon appear dark in the night sky.
What is the formula to find the weight of an object
Weight of object = mass of object x acceleration of gravity
What is weight measured in
Weight is measured in Newtons (N).
How much gravitational force is exerted per kilo on Earth
Earth exerts a gravitational force of about 10 Newtons (9.81 to be exact) for every kilogram of mass
What are tides on earth caused by
Tides on Earth are caused by the gravitational pull of the moon
Define tides
TIDES are the predictable, repeated rise and fall of sea and ocean levels.
How many times a day do tides happen
Every 24 hours the level of water in the world’s oceans and seas rises and falls twice therefore every 12 hours it is high tide or low tide.
Effects of the Moon’s and Sun’s (combination) gravitational pull.
Sun’s effect on tides is not as great as the Moon’s as it is further away.
So how do spring and neap tides happen
Aligned - Working together - New moon and full moon - Spring Tide = higher high tide
90 degrees - working against - first quarter and last quarter - Neap Tide = moderate tides
Important
Look at the neap and spring tides note and picture
What is gravity
tendency of all objects or bodies to attract or pull toward each other because of their mass.
What is mass
Mass = the amount of matter in an object
What does The pull of gravity depend on
How much mass the two objects have
How far apart the centres of the objects are
What is a spring tide
This is when the sun and moons gravitational force combine (they align), which makes the high tides higher and the low tides lower. Usually happens at the new moon and at the 2nd quarter of the phases of the moon
What is a neap tide
This is when the moon is at its 1st or 3rd quarter. It is a more moderate tide. When some of the moons force gravity gets taken away by the sun as they aren’t aligned
What are the 8 phases of the moon
Waning Crescent
Phases of the Moon (As seen from the Southern Hemisphere)
New moon
Waxing Crescent
First-quarter
Waxing Gibbous
Full Moon
Waning Gibbous
Last quarter
Waning Crescent
Nice (69th card)
Nice
Shorelines = harsh places for life to exist
Why are shorelines harsh places to live
1) Sometimes underwater and sometimes exposed to air
2) Rough seas, need to be able to hold on to rocks
3) Significant temperature difference, exposed = hot, underwater = cold
4) Must also be able to adapt to different salt concentrations as the tides come in and out.
(rain = freshwater)
What exactly is the intertidal zone
Intertidal zone: area of a shoreline that lies between the high tide line and the low tide line
(look at the picture drawn of the intertidal zone)
Adaptations of marine life that live in the intertidal zone
What adaptations did shellfish develop
Shellfish can clamp down tight on rocks and prevent water loss
What adaptations did snails develop to survive in the intertidal zone
Snails and crabs can burrow down into the sand
What adaptations did kelp develop to survive in the intertidal zone?
Kelp and other seaweeds are covered with thick slime to prevent them from drying out.
How do tides sustain life in the intertidal zone
Tides sustain life in shoreline ecosystems. The sea brings small organisms and bits of organic matter in with each tide
What lives in the uppermost part of the intertidal zone
Uppermost part - very dry - very tough organisms such as tiny snails and lichens
What lives in rocks covered by water for short times
If seaweed washes up - organisms who feed on it will be found - move away when dried
Rocks covered by water for short times - snails and shellfish main animals
What lives in rock pools
Rockpools - seaweed, small crabs
What lives in the upper beach areas in sandy shorelines
The upper beach area is dryer and usually has mostly land-living animals - ghost crabs and sand fleas
What are some organisms that burrow under the sand to hide
Organisms burrow under sand, hide under washed up material to survive - sand hoppers, small creatures that feed on algae, bacteria and organic matter
Where do white muscles live
White mussels live in the wet sand. They suck water into one and filter out anything they can eat and pump out the water through the other siphon
What are the 2 tubes that white muscles have
The two little tubes are called siphons.
What is astronomy
It is the scientific study of the universe and celestial bodies, specifically their positions and movements
When Observing predictable patterns what did the ancient people notice
Ancient people noticed that celestial objects moved in ways that could be predicted
What did early ancestors identify the celestial objects with
Early ancestors identified these objects with gods and spirits
They also related these objects and their movements to natural phenomena
What did ancient Greeks believe about the arrangement of the universe
The ancient Greeks believed the Earth was at the centre of the Universe, with the stars and planets orbiting around the Earth.
Why do we have the seven days of the week
We have seven days of the week due to the seven moving celestial bodies known to the ancient people, namely, the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn.
Question in the exam about this (Very important)
What did farmers use to mark the start of planting season
The Southern Cross, Crux, and the two bright Pointer stars were used by farmers to mark the beginning of the planting season
Question in the exam about this (Very important)
What were the 5 planets known to ancient people
Mercury, Venus, Mars, Jupiter and Saturn.
Question in the exam about this (Very important)
What is the calendar that we use today
The calendar we use, based on a solar calendar, is the Gregorian calendar, known as the “Western calendar” or “Christian calendar”.
What was the main thing that Nicolaus Copernicus
discovered
Finding that the Sun, rather than the Earth, was at the centre of the Solar system.
What was the main thing that Johannes Kepler
discovered
Rather than moving in a circle around the Sun, the planets all orbited in ellipses (ovals). He discovered that the true shape of the planets’ orbits is elliptical.
What was the main thing that Galileo Galilei
discovered
He discovered that the Moon has craters and that the Sun has dark spots which are called sunspots.
What was the main thing that Isaac Newton
discovered
His greatest discovery was that of the force of gravity
What were the other things that Isaac Newton
discovered
He derived mathematical laws to describe the motions of objects
What were the other things that Galileo Galilei
discovered
Discovered the four largest moons of Jupiter (which are now called the Galilean moons).
Venus has phases just like the Moon.
What were the other things that Nicolaus Copernicus
discovered
Copernicus correctly ordered all the planets known at the time in increasing distance from the Sun. All the orbits of the planets were circular.
Who was Isaac Newton
English physicist and mathematician and is considered one of the greatest scientists of all time.
Who was Galileo Galilei
Italian physicist, mathematician and astronomer.
Who was Johannes Kepler
German astronomer and mathematician.
Who was Nicolaus Copernicus
Polish mathematician and astronomer.
