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Friday, February 26

  1. page organicmindmap edited Organic unit Mind Map {carbon_compounds.png}
    Organic unit Mind Map
    {carbon_compounds.png}
    (view changes)
    12:24 pm
  2. page organicmindmap edited Organic unit Mind Map {carbon_compounds.png}
    Organic unit Mind Map
    {carbon_compounds.png}
    (view changes)

Saturday, May 30

  1. page Physics edited ... This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its pro…
    ...
    This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its products, and sound and ultrasound. For EMR and sound it looks at the wave properties of these phenomena, including wavelength, frequency and speed relationships, and related properties such as pitch, how these waves propogate and so on. For radioactive decay, it covers alpha, beta and gamma radiation, their properties and decay products.
    Section 1: Waves - an introduction
    ...
    propagated through spacea medium (matter or space) in the
    ...
    different energy forms. types.
    Examples include:
    ...
    and kinetic energy.
    water (ocean)
    energy (it is the same for seismic waves)
    water (ocean or fluid)
    waves: the
    ...
    kinetic energy and
    electromagnetic waves oscillate between energy stored in magnetic fields and energy in electric fields.
    In the case of all types of wave, the nature of the oscillation causes the wave-front to move along through whatever medium is carrying it (only EMR can move through empty space). A single "wave" by itself is called a pulse or a soliton. Under certain circumstances a wave can be fixed in place; this is called a standing wave.
    ...
    If you use negative index notation, and write Hz as per seconds (s to the power of -1) you would easily be able to see that units for this work out correctly. This isrecommended.
    Note: Standard form
    ...
    in standard form (which is difficult for me to do here on wikispaces at the moment because I don't seem to be able to supescript or subscript).form. This note
    ...
    k (kilo, 10^3),103), M (mega, 10^6),106), G (giga, 10^9)109) - for
    {doppler.png} Doppler effect
    When a source of waves is moving, it 'catches up' with the waves in front of it and leaves behind the waves behind it. This means that the wavelength of the waves preceding it is reduced, which increases the frequency to a stationary observer. This is illustrated in the diagram to the right, which shows waves given off by a police car travelling in the direction of the arrow (right). The waves to the right are bunched up, the ones to the left are spread out. The wdecrease in colour intensity simulates the decrease in volume as the wave energy spreads through a larger volume.
    A ripple tank simulation is given here (requires java to run).
    Doppler shift of sound: In sound waves, the doppler effect produces an increase in pitch for a sound source moving towards you. This is very noticeable with sources such as police sirens. The shift in frequency is known as a doppler shift.
    ...
    relative to EMRthe speed of light for the
    ...
    of reflected microwaves ormicrowaves.
    Sound waves: Doppler shift of
    sound waves.waves has applications in sonar and measuring fluid velocity.
    Astronomy: The Doppler effect also has applications in astronomy: we can work out the velocity of stellar objects relative to us by observing the doppler shift of known emission or absorbtion spectra from stars.
    RecentOther applications: Recent advances in
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    the windowpanes.
    A

    The sound barrier: A
    boat travelling
    ...
    greater than the speed of sound. The 'sonic boom' occurs when an object accelerates past the speed of sound . Ofand must pass through the compressions it generates.
    Of
    course, the
    ...
    speed of light. Butlight in a vacuum. However, particles can
    ...
    the speed ofat which light propagates in a
    ...
    down this page)page).
    Section 2: Electromagnetic Radiation
    Electromagnetic radiation is abbreviated as EMR. EMR consists of waves of electric and magnetic fields. They carry energy because the potential energy is constantly being transferred from the electric to the magnetic field.
    (view changes)
    10:00 pm
  2. page Physics edited Physics - EMR, radiation and sound ... papers here (I suspect this link will be dead now the …

    Physics - EMR, radiation and sound
    ...
    papers here (I suspect this link will be dead now the standard has expired).
    Note: This Achievement Standard has expired but I have left the material up because it may be of use for other science courses (I will likely appropriate parts of it as material for the new ESS standard on Physical Processes on the Earth.
    I have been aware of some editorial activity since the standard expired. Some of this is useful but it would be courteous to contact me prior to editing, or I will need to lock this page.
    If you print or distribute material from this wiki it would also be courteous to contact me.

    {wave worksheets1.doc}
    Video - discovery of the electron: This is number 2 of a series of 15 and some of the others may be useful also.
    ...
    This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its products, and sound and ultrasound. For EMR and sound it looks at the wave properties of these phenomena, including wavelength, frequency and speed relationships, and related properties such as pitch, how these waves propogate and so on. For radioactive decay, it covers alpha, beta and gamma radiation, their properties and decay products.
    Section 1: Waves - an introduction
    ...
    LyttletonWaves consist of energy propagated through space in the form of a
    ...
    between two forms of energy. For instance, in sound wavesdifferent energy forms.
    Examples include:
    sound waves:
    the energy
    ...
    kinetic energy. Waves in
    water (ocean) waves:
    the ocean oscillate beweenenergy changes between gravitational potential
    ...
    and kinetic energy,energy and electromagnetic
    electromagnetic
    waves oscillate
    ...
    electric fields. In
    In
    the case
    Wave terms
    A wave can be represented with a sine function:
    (view changes)
    9:48 pm
  3. page Physics edited ... This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its pro…
    ...
    This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its products, and sound and ultrasound. For EMR and sound it looks at the wave properties of these phenomena, including wavelength, frequency and speed relationships, and related properties such as pitch, how these waves propogate and so on. For radioactive decay, it covers alpha, beta and gamma radiation, their properties and decay products.
    Section 1: Waves - an introduction
    ...
    swells near LyttletonLyttletonWaves consist of a regular cycle between two forms of energy. For instance, in sound waves the energy changes between elastic potential energy and kinetic energy. Waves in
    ...
    empty space). A single "wave" by itself is called a pulse or a soliton. Under certain circumstances a wave can be fixed in place; this is called a standing wave.
    Wave terms
    A wave can be represented with a sine function:
    ...
    Period: this is the time between two waves and is thus the reciprocal of frequency: T = 1/f, where f is the frequency in Hz and T is the period in seconds. If the freqency was 50 Hz then the period is 1/50 second or 0.02 seconds. You can calculate the period by typing the frequency into your calculator and pressing the reciprocal button (1/x) or typing in 1 then the divided by key then the frequency then the equals button.
    Applying the wave equation
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    660 HzExample 1000:1:
    Sound waves in air travel at 330 m/s. What is the wavelength of a sound of 660 Hz (high E)?
    Working out: v = f ×λ
    (view changes)
    9:40 pm
  4. page Physics edited ... This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its pro…
    ...
    This achievement standard covers Electromagnetic Radiation (EMR), radoactive decay and its products, and sound and ultrasound. For EMR and sound it looks at the wave properties of these phenomena, including wavelength, frequency and speed relationships, and related properties such as pitch, how these waves propogate and so on. For radioactive decay, it covers alpha, beta and gamma radiation, their properties and decay products.
    Section 1: Waves - an introduction
    ...
    swells near LyttletonWaves consist of a regular cycle between two forms of energy. For instance, in sound waves the energy changes between elastic potential energy and kinetic energy.Lyttleton Waves in
    ...
    empty space). A single "wave" by itself is called a pulse or a soliton. Under certain circumstances a wave can be fixed in place; this is called a standing wave.
    Wave terms
    A wave can be represented with a sine function:
    (view changes)
  5. page Physics edited ... Period: this is the time between two waves and is thus the reciprocal of frequency: T = 1/f, w…
    ...
    Period: this is the time between two waves and is thus the reciprocal of frequency: T = 1/f, where f is the frequency in Hz and T is the period in seconds. If the freqency was 50 Hz then the period is 1/50 second or 0.02 seconds. You can calculate the period by typing the frequency into your calculator and pressing the reciprocal button (1/x) or typing in 1 then the divided by key then the frequency then the equals button.
    Applying the wave equation
    ...
    660 HzExample 1:1000:
    Sound waves in air travel at 330 m/s. What is the wavelength of a sound of 660 Hz (high E)?
    Working out: v = f ×λ
    (view changes)

Wednesday, May 7

Friday, June 28

  1. page Plate tectonics intro edited Introduction to Plate tectonics So much material on this is common to the NCEA geology courses…

    Introduction to Plate tectonics
    So much material on this is common to the NCEA geology courses, I have decided to put them all in one place.
    (view changes)

Sunday, February 3

  1. page Physics edited ... {shadow.png} Because X-rays are essentially shadows of your bones or other tissue, it is des…
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    {shadow.png}
    Because X-rays are essentially shadows of your bones or other tissue, it is desirable for the subject to be as close to the film as possible to make the shadows clear. It is also desirable to make the X-ray source as close to a point source as possible; in the early days of the technology this was difficult.
    {http://upload.wikimedia.org/wikipedia/commons/3/34/RingfoermigeSonnenfinsternis.jpg} Annular eclipseInIn a solar
    Venus and Mercury are too far away relative to the Sun for us to see the umbra, so we see only the antumbra in an event called a transit. It was the transit of Mercury in 1769 that allowed Captain Cook to pinpoint the longitude of Mercury Bay, and thus produce an exact map of the rest of New Zealand.
    A pinhole camera works on the principle that the hole is so small that all shadows are of the umbra only, producing a sharp image.
    (view changes)

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