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Q4 Eng Sci: Back to Physics, FUN FACT: Any periodic wave can be expressed…

- - - - In a series circuit, the current is the same
      - In a parallel circuit, the current is shared
        
        If bulb A, bulb B, and bulb C are in series: current of Cell = current of bulb A+ bulb B+bulb C. If the current of the cell is 0.3A, A=B=C=0.1A
  - - - In a series circuit, Voltage is shared
      - In a parallel circuit, the Voltage is the same
        
        If bulb A, bulb B, and bulb C are parallel: voltage of Cell = voltage of bulb A+ bulb B+bulb C. If the voltage of the cell is 0.3V, A=B=C=0.1V
  - - - V=Potential difference=voltage(measured in volts)
      - I=current (measured in amps)
      - R=resistance (measured in ohms)
      - the resistance determines the voltage
  - - - 1-use a pencil and a ruler
      - 2-straight lines
      - 3-never leave gaps so that components are joined
      - 4-neat and tidy
- - - - the greater the voltage, the greater the energy
- - - - Def: process of heat transfer where particles with greater thermal energy replaces particles with lower thermal energy until thermal equilibrium is reached
      - can only happen in liquid and gas
      - In liquid or gas, higher density particles goes down, lower density particles goes up; Therefore hot particles rise, cold particles fall.
      - See the diagram "Convection-how the room heats" to understand how the convection currents / circulation of air helps to distribute the cool air more evenly throughout the room, increasing the overall temperature.
      - Examples of convection: AC, Fan, Fridge, Bunsen burner, kettle, hot balloon, convection oven
    - - transfer of energy from molecule to other molecules in its vibration distance
      - happens in solid, liquid, and gas
      - Conductivity: (Fast) Copper > Aluminum > Bronze > Stainless Steel > Iron (Slow)
      - From particle to particle
    - - requires no medium for heat transfer, can transfer in solid, liquid, gas, and vacuum
      - thermal radiation travel in electromagnetic waves
      - Thermal energy in radiation can be:
        
        1- be absorbed (especially black surface)
        
        2-be reflected (especially white surface)
        
        3- be emitted (for instance, by our honourable sun
      - Also know as infrared radiation / thermal radiation
    - - temperature
      - surface area
      - heat capacity (the amount of heat needed to change temperature)
      - states of the object
      - chemical structure
      - number of molecules / density
    - - evaporative cooling: the energy is taken away by the molecules when they convert from liquid to gas because the process requires heat energy
      - How sweating maintains human maintain body temperature:
        
        Thermal energy in your blood is transferred to your sweat, through conduction, because the thermal energy in blood is higher than sweat
        
        Temperature and energy of sweat ⬆️ Temperature and energy of blood ⬇️
        
        Sweat evaporate & loses thermal energy. Since evaporation is an endothermic process, it absorbs heat from the surrounding to convert the liquid sweat into vapor
        
        Blood cooled
  - - - For example: when the ice temperature remains the same, no heat is transferring
      - For example: when the ice is melting, and its temperature rises, heat is transferring
    - - Def: thermal energy is transferred from a higher temperature region to a lower temperature region.
      - It occurs due to the natural tendency of heat to flow from areas of higher energy to areas of lower energy until thermal equilibrium is reached.
      - For example: when ice and hot water mix, the temperature of ice rises, while the temperature of hot water falls
    - - Def: a state in which two or more objects are in thermal contact and have reached a balanced temperature everywhere
- - - - visible light :smile:
        
        ultraviolet :unamused:
        
        X-rays :forbidden:
        
        Gamma :skull_and_crossbones:
        
        fast waves that is hazardous
- - - - Vibration
        
        the vibration hit adjacent air molecules and spreads (Sound can’t spread in vacuum)
        
        Arrives at outer ear
        
        Hits the eardrum and vibrates
        
        Go into the middle ear and vibrate
        
        Go into the inner ear and vibrates
        
        1 more item...
  - - - Goes straight in 1 direction
    - - Parameters:
        
        Wavelength: distance between corresponding points of two consecutive waves.
        
        Frequency: rate of vibration of the sound traveling through the air. it determines the pitch of the waves
        
        Hertz: How fast and How far a sound wave goes
        
        Amplitude: maximum displacement moved by a point on a wave. it determines the loudness of the wave
      - see the "Transverse wave diagram" picture for clear labels
      - Parts of a sound wave
        
        crest: highest point of a wave
        
        trough: lowest point of a wave