Physics

• A luminous object is an object which emits light e.g. lamp
• A non-luminous object is an object that does not emit light e.g. book
• Rectilinear propagation

  Light travels in straight lines
• Light travels at 300,000,000 m/s
• In a pinhole camera, a small hole focuses light onto a screen. This creates a real image. This is different from a virtual image that is projected onto the retina
• The image produced by a pinhole camera is inverted
• Sound waves are longitudinal and they are created from vibrations. The particles in the wave oscillate parallel to the direction of travel of the wave.
• Sound waves can be used to communicate information, but they can slo be used to transfer energy
• Speed, Distance, Time

  
• Sound can't travel through a vacuum because there is no medium for the sound waves to travel through
• Types of Electromagnetic waves:

  Radio wave Long wavelength, low frequency

  Microwave

  Infrared

  visible light

  ultraviolet

  x-ray

  gamma ray high frequency, short wavelength
• In pinhole cameras, light passes through the pinhole to project an inverted image to the film on the other end of the camera
• Additive colour mixing

  
• Reflection of light: When a ray of light approaches a smooth polished surface and the light ray bounces back

  
• Refraction of light: The bending of light when it hits another medium

  
• As the Earth moves around the Sun it rotates on its axis, so we have day and night. The side of the Earth facing the Sun is bathed in light and heat (daytime). The side of the Earth facing away from the Sun, out towards space, is darker and colder (nighttime).
• We have seasons because the earth is tilted on its axis so the sun is always in a different position, meaning the earth is always facing the sun at different times
• The only reason the moon appears to change shape is because of its orbit. We can see the moon because it reflects light from the sun so only half of the moon is ever lit.
• Calculation of gravity:

  
• A solar eclipse is when the moon moves directly between the earth and the sun
• A lunar eclipse occurs when the Moon passes between the Earth and the Sun, blocking the Sun's light from reaching the Moon
• Solar eclipse and lunar eclipse:

  
• Earth's place:

  Earth, solar system, milky way, galaxy, universe
• In order of distance from the sun they are; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
•  the speed at which planets circle the Sun is directly influenced by its gravitational attraction. Simply put, the farther a planet is from the Sun, the weaker this gravitational pull becomes
• The definition of an elliptical orbit is an oval-shaped path, like a slightly elongated circle.
• Eight lunar phases:

  
• Wavelength- distance between corresponding points on a wave ( in metres )
• amplitude- maximum amount of vibrations measured from the middle of the wave ( metres )
• Frequency- number of waves produced in one second ( hertz )
• transverse waves are perpendicular to direction of travel
• longitudinal waves move parallel with direction of travel
• transverse waves have oscillating particles that move up and down perpendicular to the direction of energy transfer
• dependant variable- the variable that is measured by the experimenter
• independent variable- the variable that is changed
• control variable- what you keep in the experiment
• constant variable- something that stays constant throughout an investigation