https://youtu.be/uv1eGonqVdQ

• Earth is the only planet that is known to sustain life in our solar system
• One of the factors that make our planet habitable is its atmosphere
• Atmosphere


  The blanket or envelope of gases surrounding the earth
• The atmosphere keeps us warm, gives us oxygen to breathe, and is where weather happens
• The atmosphere also keeps the overall temperature of the earth fairly steady, especially between night and day
• Gases in the earth's atmosphere


  • 78% nitrogen
  • 21% oxygen
  • 1% other trace gases including carbon dioxide, inert gases, hydrogen, methane, ozone
• Layers of the atmosphere


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


  • Lowest layer
  • Makes up 75% of the total mass of the atmosphere
  • Contains 99% of the atmosphere's water
  • Where wind, clouds, and weather phenomena take place
  • Air is constantly moving, causing turbulence for aircraft
• Stratosphere


  • Air flow is more stable than in the troposphere
  • Ozone layer is found here, which protects from harmful UV radiation
• Mesosphere


  • Temperature decreases with altitude
  • Coldest layer of the atmosphere
  • Burns up most meteors and asteroids before they reach the earth's surface
• Thermosphere


  • Closer to the sun, absorbs a large amount of solar radiation
  • Temperature increases tremendously with distance from the earth
  • International Space Station and space shuttles orbit in this layer
• Ionosphere


  • Ion-rich region found within the thermosphere
  • Auroras are visible in this layer
• Exosphere


  • Last layer, merges into outer space
  • Temperature varies from very hot to very cold
  • Ideal for placing artificial satellites as there is little friction
• The earth's atmosphere is divided into different layers and is made of different types of gases
• More than three quarters of earth's atmosphere is made up of nitrogen while one film is oxygen
• The remaining one percent is a mixture of carbon dioxide water vapor ozone and other trace gases
• These gases not only produce important weather features such as cloud and rain but also have considerable influence on the overall climate of the earth through the greenhouse effect and global warming
• Greenhouse


  A structure with walls and roofs made chiefly of a transparent material such as plastic or glass, useful in growing seedlings when this winter or spring before planting them in the open field
• In tropical countries greenhouses are used by commercial plant growers to protect flowering and ornamental plants from harsh weather conditions and insect attacks
• Greenhouses


  • Allow sunlight to enter but prevent heat from escaping
  • The transparent covering allows visible light to enter without obstruction and warms the inside of the greenhouse as energy is absorbed by the plants soil and other things in the building
  • The air warmed by the heat inside is retained in the building by the roof and wall
  • The transparent covering prevents the heat from leaving by reflecting the energy back into the walls and preventing outside winds from carrying it away
• The earth's atmosphere is compared to a greenhouse


  The trace gases in the atmosphere have a similar effect on the sun's rays as the glass in the greenhouse
• Greenhouse gases


  Gases that trap the sun's heat in the atmosphere, examples are carbon dioxide, methane, ozone, water vapor, and nitrous oxide
• Greenhouse effect


  The process where greenhouse gases trap the heat in the atmosphere
• The greenhouse effect is a natural process that warms the earth's surface and makes the earth much warmer than it would be without an atmosphere
• The greenhouse effect plays an important role in our survival
• Due to different human activities, more greenhouse gases are emitted into the earth's atmosphere which results in an enhanced greenhouse effect
• The enhanced greenhouse effect can lead to global warming
• Global warming


  The current rise in the average temperature of earth's air and oceans
• Sources of greenhouse gas emissions


  • Burning fossil fuels for electricity, heat, and transportation
  • Deforestation and land clearing for agriculture
  • Degradation of soils
  • Agricultural activities
  • Waste management
  • Energy use
  • Biomass burning
  • Fertilizers used by farmers
  • Industrial processes
  • Refrigeration
  • Use of consumer products
• Many of these greenhouse gases can cause earth's atmosphere to trap more and more heat, increase air temperature, and cause global warming
• Global warming is feared to melt polar ice caps and cause flooding to low-lying areas, resulting in a reduction in biodiversity, and is already changing climates around the globe causing stronger typhoons and creating many health related problems
• Analogy


  Comparison to show similarities and comparison between things that have similar features, often used to explain a principle or idea
• Types of Analogy


  • Synonym - have same meaning
  • Antonyms - opposite
  • Function - use or purpose
  • Characteristics - description of an object
  • Cause and effect - cause and effect of an action
  • Part and whole - member of the group
• Direct speech


  Use quotation marks and use the exact word or speech
• Indirect speech


  Do not use quotation marks and do not use the exact word or speech
• Parts of direct speech


  • Reporting clause
  • Reported clause
  • Reporting verb
  • Reported verb
• Steps to change direct to indirect speech


  1. Remove the quotation marks

  2. Change to that

  3. Pronoun = 3rd person

  4. Verb tense = backshifting

  5. Change place and time
• Changes in place and time


  • Now - then
  • Here - there
  • Today - that day
  • Tomorrow - the next day
  • Tonight - that night
  • Yesterday - the day before
  • Is - was
  • Are - were
  • Am - was
  • Has/have - had
  • Does/do - did
  • Shall - should
  • Can - could
  • Will - would
  • May - might
  • Must - must
• Tone


  The attitude of the author of the story or movie
• Mood


  The feeling of the readers