Earth's Atmosphere and Solar Energy
Content Standards
1
Earth's Energy Source
The learners learn that: Sunlight is the Earth's external source of energy.
Performance Standards
By the end of the Quarter, learners use reliable scientific information to identify and explain how solar energy influences the atmosphere and weather systems of the Earth and use such information to appreciate and explain the dominant processes that influence the climate of the Philippines.
Learning Competencies
Solar Energy Interaction
Explain how energy from the Sun interacts with the atmosphere.
Lesson Objectives
1
Atmospheric Layers
Describe the different layers of the atmosphere.
2
Layer Characteristics
Differentiate the layers of the atmosphere in terms of temperature and altitude.
3
Solar Energy
Explain the interaction of solar energy with the layers of Earth's atmosphere.
4
Cloud Types
Describe the types of clouds.
Learning Resources
1
Textbooks
Pavico, Josefna et.al (2013). Exploring Life Through Science. Phoenix Publishing Inc.
2
Modules
Pepito, Leah Joy Desamparado-Walan, (2020). Science – Grade 7 Learner's Module First Edition. DepEd – Instructional Materials Council Secretariat (DepEd-IMCS). Pasig City
3
Online Resources
Sunshine Trees Green Free Photo, Atmosphere structure-en.svg - Wikimedia Commons, Cloud types fr.svg - Wikimedia Commons
Introduction to Earth's Atmosphere
The atmosphere is essential for life on Earth, serving multiple critical functions. It protects us from harmful solar radiation, regulates our planet's temperature through the greenhouse effect, creates our weather systems, and provides the air we breathe.
Protection
Shields life from harmful radiation
Temperature Regulation
Maintains Earth's heat balance
Weather Systems
Creates climate and weather patterns
Life Support
Provides oxygen and other essential gases
Atmospheric Composition
Nitrogen
Oxygen
Argon
Carbon Dioxide
Other Gases
Nitrogen is the most abundant gas in the Earth's atmosphere at approximately 78%, followed by oxygen at 21%. The remaining 1% consists of argon, carbon dioxide, water vapor, and trace gases. This composition is crucial for supporting life on our planet.
Layers of the Atmosphere: Overview
The Earth's atmosphere is divided into five main layers based on changing temperature patterns. Each layer has distinct characteristics and plays different roles in protecting our planet.
Troposphere
Closest to Earth's surface, where weather occurs
Stratosphere
Contains the ozone layer that absorbs UV radiation
Mesosphere
Coldest layer where most meteors burn up
Thermosphere
Temperature increases with altitude, contains ionosphere
Exosphere
Outermost layer transitioning to space
The Troposphere
Location
Closest layer to Earth's surface, extending up to about 12 km at the equator and 8 km at the poles
Temperature
Temperature decreases with increasing altitude at a rate of about 6.5°C per kilometer
Characteristics
Contains 75% of atmospheric mass and almost all water vapor and aerosols
Significance
Where all weather phenomena occur, including clouds, precipitation, and storms
The Stratosphere
Location
Extends from the top of the troposphere to about 50 km above Earth's surface
Temperature
Temperature increases with altitude due to ozone absorption of UV radiation
Characteristics
Contains the ozone layer (15-35 km) which absorbs and scatters harmful ultraviolet radiation
Significance
Commercial aircraft typically fly in the lower stratosphere due to its stability and lack of weather turbulence
The Mesosphere
1
Location
Extends from the top of the stratosphere to about 85 km above Earth's surface
2
Temperature
Temperature decreases with altitude, making it the coldest layer of the atmosphere with temperatures as low as -90°C
3
Characteristics
Very low air density, where most meteors burn up creating "shooting stars"
4
Significance
Protects Earth's surface from meteoroid impacts
The Thermosphere
Location
Extends from the top of the mesosphere to 600 km above Earth's surface
Temperature
Temperature increases with altitude due to absorption of intense solar radiation, reaching up to 2000°C
Characteristics
Contains the ionosphere, an electrically charged layer that reflects radio waves
Significance
Makes radio communication possible around the Earth's curved surface; where auroras (Northern and Southern Lights) occur
The Exosphere
Location
Outermost layer extending from 600 km to about 10,000 km
Characteristics
Extremely thin atmosphere transitioning to space
Composition
Mainly hydrogen and helium atoms that can escape Earth's gravity
Significance
Contains many satellites orbiting Earth
The exosphere is the final frontier between Earth's atmosphere and outer space. In this region, gas molecules are so far apart they rarely collide, and some can achieve escape velocity to leave Earth's gravitational pull entirely.
The Ionosphere
The ionosphere is an electrified region within the upper mesosphere and thermosphere. It's formed when solar radiation ionizes gas molecules, creating a layer of electrically charged particles. This region is crucial for radio wave propagation around the Earth, making long-distance radio communication possible.
D-Layer (60-90 km)
Absorbs HF radio waves during daylight, forming the lowest part of the ionosphere. This layer disappears at night when solar radiation is absent.
E-Layer (90-150 km)
Reflects medium frequency radio waves, allowing signals to travel beyond the horizon. This layer is strongest during daylight hours.
F-Layer (150-600 km)
Main reflector for HF radio communications, enabling global radio transmission. This uppermost and most persistent layer of the ionosphere remains partially ionized even at night.
Temperature Variation Across Atmospheric Layers
Troposphere
Temperature decreases with altitude from about 15°C at surface to -55°C at the top (10km), creating our weather patterns.
Stratosphere
Temperature increases with height due to ozone absorbing UV radiation, rising from -55°C to around 0°C at the upper boundary.
Mesosphere
Temperature decreases again, reaching the coldest point in the atmosphere (-90°C) at the mesopause around 80km altitude.
Thermosphere
Temperature increases dramatically with height due to direct absorption of solar radiation, reaching up to 300°C and higher in the upper regions.
Temperature varies dramatically across the atmospheric layers due to differences in radiation absorption, air density, and composition at different altitudes.
The Ozone Layer
Ozone Molecule (O₃)
A molecule consisting of three oxygen atoms that absorbs ultraviolet radiation
UV Protection
Absorbs 97-99% of the sun's high-frequency ultraviolet light
Ozone Depletion
Thinning of the ozone layer due to chlorofluorocarbons (CFCs) and other ozone-depleting substances
The ozone layer is located primarily in the stratosphere, between 15 and 35 kilometers above Earth's surface. It serves as a shield from the sun's harmful ultraviolet radiation, protecting life on Earth from potential damage.
Solar Energy and the Atmosphere
Incoming Solar Radiation
The sun emits electromagnetic radiation across the spectrum, including visible light, ultraviolet, and infrared
Atmospheric Interaction
Different wavelengths interact differently with atmospheric gases - some are absorbed, some scattered, some pass through
Energy Distribution
About 30% of incoming solar radiation is reflected back to space, 20% is absorbed by the atmosphere, and 50% reaches Earth's surface
Earth's Energy Balance
The balance between incoming and outgoing radiation determines Earth's temperature
The Greenhouse Effect
Solar Radiation
Short-wave radiation enters atmosphere
Surface Absorption
Earth's surface warms and emits infrared radiation
Heat Trapping
Greenhouse gases absorb and re-emit infrared radiation
Warming Effect
Trapped heat warms the lower atmosphere
The greenhouse effect is the ability of atmospheric gases to keep the planet warm by trapping heat. Without this natural process, Earth would be too cold for life as we know it. Greenhouse gases like carbon dioxide, methane, and water vapor absorb infrared radiation emitted by Earth's surface and re-radiate it in all directions, preventing heat from escaping too quickly into space.
Introduction to Clouds
Clouds are visible accumulations of water droplets or ice crystals suspended in the atmosphere. They form when water vapor condenses around tiny particles like dust, pollen, or pollution. Clouds play a crucial role in Earth's energy balance by reflecting sunlight back to space and trapping heat below.
Cloud Classification by Altitude
High Clouds (5-13 km)
Composed primarily of ice crystals due to cold temperatures at high altitudes
Middle Clouds (2-7 km)
Composed of water droplets, sometimes mixed with ice crystals
Low Clouds (0-2 km)
Composed mainly of water droplets
Vertical Development
Can extend across multiple altitude levels
High Clouds
Cirrus
Thin, wispy clouds made of ice crystals that often indicate fair weather but may signal an approaching weather front
Cirrostratus
Thin, sheet-like clouds that can cover the entire sky and often create halos around the sun or moon
Cirrocumulus
Small white puffs arranged in groups or lines, sometimes called a "mackerel sky" due to their rippled appearance
High clouds typically form above 5,000 meters (16,500 feet) in mid-latitudes. They are primarily composed of ice crystals due to the extremely cold temperatures at these altitudes.
Middle Clouds
Altostratus
Gray or blue-gray sheet-like clouds that can cover the entire sky. The sun may be visible through these clouds as a dim spot. They often precede storms with continuous precipitation.
Altocumulus
White or gray patches of clouds, often in rows or waves. They may indicate moisture and instability at mid-levels of the atmosphere and can precede thunderstorms, especially on warm, humid mornings.
Middle clouds typically form between 2,000 and 7,000 meters (6,500 to 23,000 feet). They are composed primarily of water droplets, though they may contain ice crystals when temperatures are cold enough.
Low Clouds
Stratus
Uniform gray layer that often resembles fog but doesn't reach the ground. May produce drizzle or light snow.
Stratocumulus
Low, puffy gray or white clouds that appear in patches or rolls. Usually have dark spots underneath but rarely produce precipitation.
Nimbostratus
Dark gray, wet-looking clouds that produce continuous rain or snow. They form a thick, uniform layer that completely blocks the sun.
Low clouds form below 2,000 meters (6,500 feet) and are primarily composed of water droplets. They often appear more dense and opaque than clouds at higher altitudes due to their greater water content.
Clouds with Vertical Development
Cumulus
Fluffy clouds with flat bases and rounded tops that develop vertically. They range from small "fair weather" cumulus to towering cumulus that can develop into cumulonimbus.
Cumulonimbus
Thunderstorm clouds that can extend from as low as 300 meters to over 12,000 meters in height. They produce heavy rain, lightning, thunder, and sometimes hail or tornadoes.
Vertically developed clouds can span multiple altitude classifications, sometimes extending from the low levels of the atmosphere all the way to the top of the troposphere. They form when warm, moist air rises rapidly through the atmosphere in unstable conditions.
Cloud Formation Process
Evaporation
Water evaporates from Earth's surface into water vapor
Rising Air
Warm, moist air rises due to convection, frontal lifting, or orographic lifting
Cooling
As air rises, it expands and cools due to lower atmospheric pressure
Condensation
When cooled below dew point, water vapor condenses around condensation nuclei
Cloud Formation
Billions of water droplets or ice crystals form, becoming visible as clouds
Solar Energy and Weather
The sun is the primary driver of Earth's weather systems. Uneven heating of Earth's surface creates temperature and pressure differences that drive atmospheric circulation. This circulation, combined with Earth's rotation and the distribution of land and water, creates our complex weather patterns and climate systems.
Solar Heating
Sun heats Earth's surface unevenly, with the equator receiving more direct radiation than the poles.
Air Movement
Temperature differences create air pressure gradients that generate winds and global circulation patterns.
Water Cycle
Solar energy drives evaporation, condensation, and precipitation processes that distribute water around the planet.
Weather Patterns
The interaction of solar heating, air movement, and water cycle results in diverse weather phenomena from clear skies to severe storms.
Climate of the Philippines
Tropical Maritime Climate
The Philippines has a tropical maritime climate characterized by high temperatures, high humidity, and abundant rainfall. This is directly influenced by solar energy and its interaction with the surrounding ocean waters.
Monsoon Seasons
The southwest monsoon (Habagat) brings heavy rainfall from May to October. The northeast monsoon (Amihan) brings cooler, drier air from November to April. These seasonal wind shifts are driven by differential heating of land and ocean.
Tropical Cyclones
The Philippines experiences an average of 20 tropical cyclones annually, with about 8-9 making landfall. These powerful storms form over warm ocean waters heated by solar energy.
Solar Energy and Philippine Climate
Intertropical Convergence Zone
The Philippines is located within the ITCZ, where northeast and southeast trade winds meet, creating a band of clouds and precipitation
El Niño and La Niña
These Pacific Ocean temperature fluctuations significantly impact Philippine rainfall patterns, causing droughts or flooding
Land-Sea Breeze
Daily temperature differences between land and sea create local wind patterns in coastal areas
Orographic Effect
Mountains force moist air upward, causing cooling and precipitation on windward sides and creating rain shadows
Formative Assessment
Multiple-Choice Questions: Encircle the letter of the best answer.
Question 1
What is the CORRECT order of earth's atmospheric layers from its surface?
Question 2
Which layer of atmosphere is the coldest?
Question 3
What happens to the temperature in the troposphere as the altitude increases?
Question 4
In which layer of the atmosphere does passenger aircraft fly?
Question 5
Which best describes the function of the atmosphere?
Formative Assessment (Continued)
6. Which best describes the greenhouse effect?
7. In which layer of the atmosphere makes the reception of radio waves around the earth possible?
8. Ozone layer serves as shield from the incoming solar radiation. In which layer of the atmosphere contains the large amounts of ozone?
9. Which is TRUE about stratosphere?
10. What is the most abundant gas in the earth's atmosphere?
Formative Assessment (Final Questions)
1
Which is the electrified region of the upper atmosphere?
2
What is the basis for the division of the layers of the atmosphere?
Answer Key:
1. D
5. B
9. D
2. A
6. C
10. B
3. A
7. D
11. A
4. B
8. B
12. A
Key Takeaways: Atmospheric Layers
Layer
Altitude
Temperature Trend
Key Features
Troposphere
0-12 km
Decreases with height
Weather occurs here
Stratosphere
12-50 km
Increases with height
Contains ozone layer
Mesosphere
50-85 km
Decreases with height
Coldest layer, meteors burn
Thermosphere
85-600 km
Increases with height
Contains ionosphere
Exosphere
600-10,000 km
Very high temperature
Transitions to space
Key Takeaways: Solar Energy and Atmosphere
Energy Source
The Sun is Earth's primary external energy source, driving atmospheric processes and weather systems
Protection
The atmosphere shields Earth from harmful radiation and regulates temperature through the greenhouse effect
Weather Formation
Solar energy creates temperature differences that drive air movement, cloud formation, and precipitation
Climate Patterns
Long-term solar energy distribution creates global climate patterns, including those affecting the Philippines
Summary and Conclusion
Atmospheric Structure
Earth's atmosphere consists of five main layers with distinct properties
Temperature Patterns
Each layer has characteristic temperature trends that define its boundaries
Solar Interactions
Solar energy interacts differently with each atmospheric layer
Weather Systems
These interactions create our weather and climate patterns
Cloud Formation
Understanding cloud types helps predict weather conditions
The Earth's atmosphere is a complex system that interacts with solar energy in various ways across its different layers. From the weather-producing troposphere to the protective stratosphere and beyond, each layer plays a vital role in maintaining Earth's habitability. Solar energy drives these atmospheric processes, creating the weather patterns and climate systems that affect our daily lives, particularly in regions like the Philippines with its tropical maritime climate.