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Lesson 1- Earth as a unique planet.pptx
- 1. EARTH AS A UNIQUE PLANET Lesson 1
- 4. EARTHโS LOCATION IN THE SOLAR SYSTEM
- 6. EARTHโS SIZE AND MASS
- 10. ESSAY โขAnswer the following questions focusing on the content of our lesson. Write your answers on a paragraph form with five (5) to six (6) statements per paragraph. 1. What is the significance of understanding the characteristics of the earth? 2.Which of the aforementioned unique characteristic of earth do you like the most and why?
Editor's Notes
- Earth is a unique planet. It is the only planet capable of sustaining life because of the right combination of elements, molecules and ions that react under the right physical conditions to make up the processes supportive to life. It has an atmosphere that serves as a thermostat that is necessary to regulate its surface temperature. It also contains the right amount of liquid water and oxygen that serve as essential compounds needed in the biological processes such as cellular respiration and photosynthesis. Earthโs scientists describe this planet as a life support system. It is in the perfect location in the solar system. The mechanism of its rotation and revolution are well-synchronized to bring about changes in the weather and climate. Its tilt relative to the orbital plane promotes seasons as we know it.
- In the Milky Way galaxy alone, there are about 1 billion planets. However, only the earth is habitable. Other planets may be too hot or too cold. They may also be too big or too small. Other planets may not have an atmosphere or a magnetic field or may not be in an orbit at all. Fortunately, planet earth possesses all the features and characteristics that make it habitable for all living forms. Let us go through with each one of earthโs characteristics.
- Earth is the third planet in the solar system. It is considered to be one of the inner planets next to Venus. Its distance from the sun is about 93 million miles and it takes about 500 seconds for sunlight to reach the earthโs surface. This distance from the sun is enough to support life. As we learned in our previous science lessons, the producers, or organisms that manufacture their own food utilize the energy from the sun and convert it into chemical energy that marks the beginning of food chains and complex food webs. Below is the chemical equation called photosynthesis which utilizes solar energy, converting it into food that will be made available to life forms. The distance between earth and sun is strategic enough to put this essential chemical equation to work. If the earth had been too close to the sun, its surface would have been dry and lifeless just like mercury and Venus. If it had been too far like Uranus and Neptune, it would have been cold and dark. Earthโs tactical location also prevents it from planetary collisions. The fact that Jupiter, the biggest planet in the solar system is our neighbor puts planet earth in an advantage as far as life is taken into consideration. Between Mars and Jupiter are asteroid belts. Since Jupiter is so massive, its gravity is so strong that it pulls asteroids and other space debris towards itself, warding it away from the earth.
- The atmosphere is the gaseous layer that envelops the earth. It regulates the planetโs surface temperature. Most of the element that makes up the atmosphere is nitrogen (about 78%). If we compare the earth to an apple, the atmosphere is relatively the size of its peel. However, due to its cooling mechanisms, it protects the living things to be directly affected with harmful radiation. Photodissociation is the process by which ozone molecules (O3) in the stratosphere is broken down (decomposition reaction) into elemental oxygen (O) and diatomic oxygen (O2) as it absorbs high energy solar radiation and then convert it into low energy radiation. This way, harmful high-energy radiation will not go directly into the earthโs surface.
- The size of the earth also plays a vital role in keeping its life support system afloat. The size of a planet is directly related to its gravitational pull. The acceleration due to gravity helps the planet maintain its atmosphere. If the earth had been bigger than it is, its gravity would have been stronger to the point of not keeping an atmosphere around it. If it had been too small on the other hand, it would not have been able to sustain a gaseous layer since its gravity is too weak. Earth interacts gravitationally with the sun. Its gravity as a result of its mass, also keeps the moon along its orbit. The moon, as the only natural satellite of Earth, plays a vital role in the existence of all life forms.
- Our planet is a big ball of magnet. Its geographic north serves as its magnetic south and its geographic south serves as its magnetic north. The region around earth that is dominated by magnetic field is called magnetosphere which extends to about 65, 000 km in space. Its magnetic properties are the result of its internal activities involving electric current flowing in the molten core made possible by its rotation. The inner core is the solid layer of the earth and is made predominantly of iron. Since it is compressed by pressure due to earthโs gravity, it is solid in form. The outer core on the other hand, is liquid in form and is made up predominantly of iron and nickel. As the earth spins, the flow of liquid iron and nickel in the outer core produces electric current, thereby producing magnetic field. The invisible magnetic field then passes through the earthโs layer and into the space. This magnetic field shields earth from the harmful surge of charged particles from the sun called solar winds and other space weather. Most of the particles of solar winds cannot cross the earth because it gets deflected by the magnetic field. Without the magnetic field, earth would have been as hot and lifeless as Mars.