Reviewer for Periodical Test Grade 8 PDF

Reviewer for Periodical Test Grade 8 Seismic Waves P-waves - first to be recorded by a seismograph - also called a primary wave S-waves - second to be detected by a seismograph - second to be recorded by seismograp...

Reviewer for Periodical Test Grade 8 Seismic Waves P-waves - first to be recorded by a seismograph - also called a primary wave S-waves - second to be detected by a seismograph - second to be recorded by seismograph - also called a secondary wave L-waves - third to be recorded by a seismograph - has the greatest amplitude - low frequency - named after Augustus Edward Love R-waves - travels the slowest - exist on any free surface in a continuous body Tropical Cyclones Tropical Cyclones - PAG-ASA classifies tropical cyclones based on their maximum sustain winds Hurricanes vs Typhoons (differ on where they are formed) - Hurricanes: formed in the North Atlantic Ocean, affecting most of the Caribbean Sea - Typhoons: formed in the Northwest Pacific Ocean, affecting Southeast Asia, the West Philippine Sea, and mostly Japan PAG-ASA’s Tropical Cyclone Categories Classification Maximum Sustained winds near the Center (km/h) Tropical Depression (TD) < 61 Tropical Storm (TS) 62 to 88 Severe Tropical Storm (STS) 89 to 117 Typhoon (TY) 118 to 184 Super Typhoon (STY) 185 or higher 3 Basic Stages in the Development of a Tropical Cyclone Stage 1: Formative/ Origin Stage - the state in which a tropical cyclone begins to develop when the conditions needed for its formation are met Stage 2: Mature Stage - when a tropical cyclone is already packed with raging winds and swirling towering clouds, it is in the mature stage Stage 3: Dissipation Stage - when a tropical cyclone is weak and can disappear anytime with lack of moisture, it is in the dissipation stage A tropical cyclone starts to form when the following coinciding conditions are met: 1. Tropical Oceans - the characteristics of tropical oceans – large, still, and warm are needed to start the formative stage of tropical cyclones 2. Convergence of Low Altitude Winds - as warm air develops on the ocean surface, it expands and rises to the atmosphere creating a low- pressure area (LPA) - the surrounding low altitude winds or trade winds converge and then replace the warm air which likely rises to the atmosphere 3. Latent Heat of Condensation -as the condensation of water continues, the latent heat energy stored in it is released 4. Coriolis Effect - force rendered by Earth’s rotation due to its tilted axis  - affects the rising air from the surface to spiral around the center of the thick clouds forming the eye of the storm Typhoons in the Philippines Philippines - prone to typhoons because of its surrounding oceans and its proximity to the equator Intertropical Convergence Zone (ITCZ) - the area surrounding the equator where tropical cyclones form Philippine Atmospheric, Geophysical , and Astronomical Services Administration (PAG-ASA) - a national institution dedicated to provide flood and typhoon warnings, public weather forecasts and advisories Philippine Area of Responsibility (PAR) - the area where the Philippines monitors tropical cyclones and issues warnings PAR Coordinates: Examples: 5°N-115°E 5°N-119°E (inside the PAR) 15°N-115°E 3°N-112°E (outside 21°N-120°E the PAR) 25°N-120°E 15°N-125°E (inside the PAR) 25°N-135°E 5°N-135°E How Landmasses and Bodies of Water affect Typhoons Both landmasses and bodies of water affect tropical cyclones. Cold Oceans in Colder climate regions - tropical cyclones completely dissipate Warm, moist air – access to warm and moist air strengthens a tropical cyclone Mountains – presence of mountains can weaken the typhoon by as much as 50 percent Plains and Highlands – when passing over plains and highlands, tropical cyclones strengthen due to an increase in surface friction Comets, Meteors, and Asteroids Comets Meteors Asteroids Dirty snowball Shooting stars Planetoid Mixtures of ice and dust Falling stars Dwarf/miniature planets Comets When it Appears Last Appearance Next Appearance Halley’s Commet Every 75-76 years February 1986 Mid-2061 Comet Tempel 1 Every 5-6 years 1867 2016 or 2017 Comet Tempel - Tuttle Every 33 years 1865 May 2031 Meteor Shower Radiant Point Occurrence Place of Observation Orionids Constellation Orion the October, every year Northern and Southern Great Hemisphere Perseids Constellation Perseus Mid-August, every year Northern and Southern Hemisphere Geminid Constellation Gemini Early December, every year Northern and Southern Hemisphere HAPPY STUDYING