Science reviewer

• Atmosphere


  The great mass of air that envelops Earth's surface and is held in place by the planet's gravitational force
• Composition of the atmosphere

  • 78% nitrogen
  • 21% oxygen
  • 1% argon
  • 0.038% carbon dioxide
  • Other trace amounts of inert gases
• The atmosphere has been responsible for the development and protection of life on our planet
• The composition of the atmosphere is gradually changing because of human activities, and these changes might eventually lead to other changes in Earth
• Layers of the atmosphere

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Exosphere
• Troposphere


  The layer nearest to the Earth's surface and this is also the zone where weather occurs
• Stratosphere


  Contains a layer called ozone (O3) which is an excellent absorber of the ultraviolet radiation emitted by the sun
• Daytime heating of land and sea

  1. Land heats up faster than sea

  2. Warm air above land rises

  3. Cooler air sinks and spreads along the surface

  4. Air moves from high pressure to low pressure creating wind

  5. Sea breeze forms
• Nighttime cooling of land and sea

  1. Land cools down faster than sea

  2. Warm air above sea rises

  3. Air over land moves toward rising warm air

  4. Cooler air sinks

  5. Air moves from high to low pressure creating wind

  6. Land breeze forms
• Land breeze


  The moving air or wind from land to sea during the nighttime
• Sea breeze


  The moving air or wind from sea to land during daytime
• Monsoon


  A seasonal wind of the Indian Ocean and Southern Asia, blowing from the southwest in summer and from the northeast in winter
• Northeast monsoon (Amihan)


  Monsoon draws "cold, dry air" from Siberia, China, and Japan
• Southwest monsoon (Habagat)


  Monsoon in the Philippines characterized by hot and humid weather, frequent heavy rainfall, and a prevailing wind from the west
• Air pressure


  The force exerted by the gas molecules that make up the air on a given surface area
• Humid air


  Air containing a lot of water vapor
• High-pressure area


  The place where cool air is sinking
• Low-pressure area


  The place where warm air is rising
• Climate


  Refers to long term weather condition in a region
• Weather


  The condition of the atmosphere at a particular place and time
• Intertropical Convergence zone


  Converge in the tropics and rise to form rain clouds, characterized by heavy rainfall and most of the precipitation
• Latitude


  Imaginary lines on a map or globe that measure the distance in degrees north or south of the equator, extending horizontally from east to west
• Longitude


  Imaginary lines on a map or globe that measure distance in degrees east or west of the prime meridian, extending vertically from pole to pole
• Prime Meridian


  The great circle on the Earth's surface passing through the North and South Poles, which is considered 0 degrees longitude
• Most Essential Learning Competencies

  • Using models, relate:
  • the tilt of the Earth to the length of daytime;
  • the length of daytime to the amount of energy received;
  • the position of the Earth in its orbit to the height of the Sun in the sky.
• The world we live in is always in constant motion
• How the Earth moves

  1. It spins on its axis

  2. It circles the Sun
• The Earth is speeding around the Sun at 30 k/s
• We cannot feel these motions, but we know that the Earth is in motion as we see the Sun, Moon, Stars, and other heavenly bodies whenever we observe the sky
• All these constant motions affect the length of day and night, the climate we experience, the different seasons, and the energy that we receive from the Sun
• Earth


  • It has two regions: The Northern hemisphere and the Southern hemisphere
  • It is tilted 23.45 degrees from the North pole
  • If the North pole is tilted towards the Earth, the temperature is warmer; if it is tilted away, the temperature is colder
• Tilt of the Earth

  1. In the month of June, the Northern hemisphere is tilted towards the Sun while the Southern hemisphere is tilted away from it

  2. In the month of December, the Southern hemisphere is tilted towards the Sun while the Northern hemisphere is tilted away from it
• When Earth is closest to the Sun

  The days are longer, and nights are shorter
• When Earth is far from the Sun

  The nights are longer, and days are shorter
• Perihelion


  When the Earth is at its closest point to the Sun
• Aphelion


  When Earth is at the farthest point from the Sun
• Most Essential Learning Competencies

  • Using models, relate:
  • the height of the Sun in the sky to the amount of energy received;
  • the latitude of an area to the amount of energy received;
  • tilt of the Earth and the seasons.
• During the day, you have the energy to do your activities while at night, you get the urge to sleep and rest
• During the Summer, your body tends to do different activities but during the rainy seasons or colder days in December, your body has the urge to rest and enjoy the cold weather
• The greatest source of energy is the Sun. Plants and animals including humans receive energy from the Sun. Starting from the food we eat and the heat we directly receive