Science - Gr 7

• Pitch is the highness of the sound. The higher the frequency is the higher the pitch.
• Loudness is how soft or how intense the sound is. determined by the amplitude of the sound waves.
• Timbre is differenctiating 2 sounds that have the sa,e pitch and loudness.
• Motion


  Change of position of an object
• Reference point


  Used for comparison to determine if something is in motion
• Scalar quantities


  • Distance
  • Speed
  • Acceleration
• Vector quantities

  • Displacement
  • Velocity
• Distance is the total length of the path travelled by an object
• Total distance is the sum of the distances between all the points in the path
• Acceleration


  The rate of change of velocity
• Velocity


  The rate of change of displacement
• 1. DISPLACEMENT

  • Same direction = addition
  • Opposite direction = subtraction 
  • Different direction = pythagorean theorem

  
• 1. SPEED

   

  • Speed = D/T
  • Time = D/S
  • Distance = T x S

  
• Velocity

  • Velocity = D/T
  • Displacement = V x T
  • Time = D/V

  
• Wave


  A vibration or disturbance in space that moves from one place to another
• A wave can transfer energy, but it does not transfer matter from one place to another
• Types of waves

  • According to medium
  • According to the direction of motion of the particles in a medium
• Medium


  Substances that all sound waves travel through and need to have in order to move
• Mechanical wave


  Requires a medium to transfer energy (solid, liquid, gas) (not allowed in space)
• Mechanical wave


  • Sound
• Electromagnetic wave


  Does not require a medium to transfer energy, can transfer energy through a vacuum
• Examples of EM wave

  • Radio wave
  • Microwave
  • Infrared
  • Visible light
  • Ultraviolet
  • X-ray
  • Gamma wave
• Sun is the main source of our life.
• Dispersion is a phenomenon where a prism seperates white light
• Vibration is a repeated motion by a back and forth or up and down movement of a object.
• A wave is a trsveling disturbance that carried energy from one place to another with or without medium.
• Medium is a substance or material that carries the wave
• example of

  
• Contact force

  Applied force, friction, normal force, air resistance, tension
• Applied force


  Push or pull
• Friction


  Restriction of 2 objects that rub against each other
• Normal force


  Exerted upon an object that's in contact with another stable object
• Air resistance


  Acts upon an object as they travel through the air
• Tension


  Transmitted through a string that is being pulled on both sides