science q2

• circuit breaker - are used at home and in building to prevent the overloading of circuits. Overloading can happen when too many devices are connected to the same socket, and as a result, draws current that can exceed the capacity of the circuit
• fuses - fuses are also to prevent a circuit system from overloading. S fuse is composes of resistance wire with a prescribed melting point to use in all household circuits
• residual current devices (RCD) - it is also known as safety switch, is a device that is how required to be installer in any new buildings as a standard fuse box equipment. An RCD is used to prevent a current from leaking in a household circuit. It detects any current that flows from the circuit to the earth through a person or other means. And the, it breaks the circuit, stopping the flow of current before it can cause damage or electric shock
• earthing or grounding - is the process of connecting a machine, appliance or any electrical device to conducting rod attached to the ground. This process allows the excess charge on the chassis of the electrical device to flow safely to the ground.
• double insulation - means that the wiring used in appliances have a second layer of insulation to ensure that the people using the appliance will be protected from receiving an electrical shock in case the first layer of insulation fails
• five safety tips

  1. replace or repair damages power cords
  2. dont overload your outlets
  3. avoid extension cords as much as possible
  4. keep electrical equipment or outlets away from water
  5. protect small children from hazards
• a fault is a fracture or zone of fractures between two blocks of rock . Faults allow the blocks to move relative to each other
• the three types of faults are normal fault , reverse fault , strike slip fault
• normal fault - occurs when one block moves downwards relative to another block. The hanging wall is the upper block while the footwall is the lower block
• reverse fault - occurs when one block moves upwards relative to another block. The hanging wall is the lower block while the footwall is the upper block
• strike-slip fault - occurs when both blocks slide past each other horizontally. There is no movement vertically
• an earthquake is an intense shaking of earths surface. The shaking is cause by movements in earths outermost layer
• the earth is made of four basic layers: a solid crust, a hot, nearly solid mantle, a liquid outer core and a solid inner core
• tectonic plates are constantly shifting as they drift around the viscous, or slowly flowing, mantle layer below
• the solid crust and top, stiff layer of the mantle make up a region called lithosphere
• the energy released of an earthquake that penetrates and passes through the interior in all directions is called seismic waves
• seismic waves come from the greek word "seismo" which means earthquake
• there are two main types of seismic waves, these are body waves and seismic waves
• body waves travel within the earth while surface waves travel along its surface
• body waves are of a higher frequency than surface waves
• the two types of body waves are primary waves and secondary waves
• primary waves (p waves)
• secondary waves (s waves)
• primary waves can travel as fast as 1.6 to 8 km/sec or 1 to 5 miles per second in the earths crust
• secondary waves also known as shear waves or transverse waves
• an s wave is slower than the p wave
• surface waves travel only though the crust, surface waves are of a lower frequency than body waves
• it is surface waves that are almost entirely responsible for the damage and destruction associates with earthquakes
• love waves or L waves is the first kind of surface wave, it is named after augustus edward hough love
• love waves are the fastest surface waves and moves the ground hotizontally, causing it to twist from side to side
• rayleigh waves or R waves is the other kind of surface wave and named for john william strutt, lord rayleigh
• most of the shaking felt from an earthquake is due to the rayleigh waves, which can be larger than the other waves
• the philippines is locates in the western part of north pacific ocean
• tropical cyclones form over warm waters anywhere within this area
• PAGASA forecasters use three domains:

  philippine area of responsibility (PAR)

  tropical cyclone advisory domain (TCAD)

  tropical cyclone information domain (TCID)
• PAGASA is obliged to provide information about the weather disturbance to the public
• PAR is the smallest and innermost monitoring domain
• TCAD is the "middle domain" located between the PAR and TCID
• TCID is the largest and the outermost monitoring domain of PAGASA
• the enactment of republic act of 10121 otherwise known as the philippine disaster risk reduction and management