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However, not all rain can reach the surface of the earth. Some evaporates while falling through dry air. This is what we call as “virga”, a phenomenon which is often seen in hot, dry desert regions.
4. Contoh Text Explanation tentang Fenomena Alam IV
Tornado
General Statement
Tornadoes are vertical funnels of rapidly spinning air. Their winds may top 250 miles an hour and can clear a pathway a mile wide and 50 miles long. Also known as twisters, tornadoes are born in thunderstorms and are often accompanied by hail. Giant, persistent thunderstorms called supercells spawn the most destructive tornadoes. Tornadoes only form when a thunderstorm has a particular combination of winds.
Explanation
Air rising in a thunderstorm can begin to spin when it is affected by winds blowing it in different directions. It starts to rise and is pushed to the side by the wind. It rises a bit more and is jostled again by wind moving in another direction. Winds moving in different speeds and directions at different altitudes cause the rising air to start spinning.
Air that spins as it rises is typical in a supercell, the strongest type of thunderstorm, but not all spinning air creates a tornado.
For a tornado to form, there also needs to be spinning air near the ground. This happens when air in the storm sinks to the ground and spreads out across it in gusts. Gusts of warmer air rise and gusts of cooler air sink as they blow across the land. If there are enough rising and sinking gusts, the air near the ground starts spinning.
The spinning air near the ground speeds up as it is drawn inward toward its axis of rotation. This happens in the same way that figure skaters spin faster when their arms are drawn in rather than when their arms are outstretched. This is called conservation of angular momentum.
The rotating air moves horizontally across the ground, and can be tilted vertically by the force of the rising, rotating air. This allows a tornado to form.
Conclusion
Most tornadoes form during supercell thunderstorms, but not all supercell thunderstorms produce tornadoes. Usually, the rotating air near the ground doesn’t rotate fast enough for a tornado to form. If the rotating air near the ground is very cold, it will spread away from the storm along the ground and slow down like a figure skater with extended arms, and a tornado will not form.
5. Contoh Text Explanation tentang Fenomena Alam V
Baca Juga: 10 Contoh Analytical Exposition Lengkap dengan Penjelasan Strukturnya
Human Respiration
General Statement
Do you know how your body gets oxygen from the air and removes carbon dioxide from your body? Right! It’s because of the respiratory system. Do you know how it works? The following explanation is written to help you understand the process clearly.
Explanation
The first phase of respiration is breathing in or inhalation. This process brings air from outside the body into the lungs. From the lungs, the oxygen moves through blood vessels to the heart which then pumps the oxygen-rich blood to all parts of the body. Oxygen then moves from the blood-stream into the cells, which completes the first phase of respiration. In the cells, oxygen is used in a separate energy-producing process which produces carbon dioxide as a byproduct.
The second phase of respiration begins when the carbon dioxide moves from the cells to the bloodstream which carries carbon dioxide to the heart. Then, it pumps the carbon dioxide-laden blood to the lungs.
Conclusion
