DIU Activities > Alumni
Sharpen Your General Knowledge
Shamim Ansary:
Why do migrating birds fly in a V formation?
Migrating birds fly in a V formation because it gives them the best of both worlds, reducing air resistance while allowing the geese or ducks in the back to see where they’re going.
Think of the V formation as the front of a boat cutting a path through water.
The first fowl in the V formation cuts through the air and blocks some of the air and wind resistance for the two birds behind it, allowing them to glide through the air using less energy.
Those birds do the same for the ones behind them, and so on all the way through the V. In this way, the birds can travel long distances with fewer rest stops during migration.
When the front bird gets tired, it drops back, and another takes its place at the front.
Shamim Ansary:
Which Other Birds Lay Eggs in Another Mother Bird’s Nest Besides Cuckoos and Why?
The South American black-headed duck, the African honeyguides, and the whydas are some examples of parasitic breeder birds.
cowbird
The best known bird to North Americans that lays eggs in other nests is the brown-headed cowbird.
These birds have actually evolved the capability to mimic the size and color of other birds’ eggs. Aiding their survival further, they’re well-known song mimics as well.
Cowbirds have been raised by at least 206 different species of birds.
Sure, we humans can get sick and tired of raising our own kids, especially after hearing another one of those long, grueling explanations of why Dark Charazard can whip Ancient Mew in a Pokemon battle.
But birds, presumably, don’t shirk their parenting responsibilities for emotional reasons.
So why do these birds lay their eggs elsewhere? It’s a matter of simple reproduction, really.
When a bird drops off her young in another bird’s nest, it frees her up to do more egg-laying.
Shamim Ansary:
How Fast Is the Earth Moving Though Space?
How fast earth is moving through space depends on what you’re comparing it to.
The Earth is moving in several different directions at the same time, each at breakneck speed.
Rotating on its axis, the Earth goes 460 meters a second (roughly 1,000 miles per hour) at the equator.
Going around the sun, the Earth moves about 30 kilometers per second (roughly 67,000 miles per hour).
Our solar system whirls around the center of our galaxy at about 220 kilometers per second (about 490,000 miles per hour).
Meanwhile, our entire galaxy is traveling at a speed of about 1,000 kilometers per second (620 miles per hour) toward a region of space called the Great Attractor, which is about 150 million light years away. Hold on tight!
Shamim Ansary:
Does the Sun Move?
In ancient times, as people watched the sun move across the sky each day, they thought that the sun traveled around the earth.
Scientists later found out that the sun remains in one place while the earth and the other planets travel around it. But we know now that the sun moves too!
The sun is just one star in a huge group of stars called a galaxy. Our galaxy, called the Milky Way, is spinning around like a phonograph record. And the sun is traveling around the center of the galaxy at a speed of about 481,000 miles per hour. At that speed, the sun will travel around the center of the Milky Way once in about 225 million years.
The Milky Way itself is moving around the center of a group of galaxies, like a planet moving around the sun. And this group of galaxies may be traveling around the center of the universe. So the sun is really moving in two or three directions at once!
Like the sun, all other stars are traveling through space at high speeds, but they’re so far away that to us, they look like they never move!
Shamim Ansary:
How Does a Radio Work?
At the radio studio, the sound waves of a program go into a microphone that has electrical current running through it. These sound waves create vibrations in the current as they travel through wires to a control room.
There, technicians control their volume and send them out through a transmitter. An antenna on the transmitter sends these electrical waves out through the air as radio waves. Radio waves travel through space in all directions, just as waves of water spread out when a pebble is dropped into it.
Each radio station is assigned a particular channel, or electrical path, by the Federal Communications Commission. This channel, called the station’s frequency, must be followed exactly.
You cannot see, hear, or feel radio waves in the air, but the radio in your home, which has an antenna either on the inside or outside, picks up these waves from many stations at the same time. By turning the tuning dial, you can select the station you want to listen to.
What happens is that the current in your radio tunes in to the same frequency as the radio waves sent out by the station you have chosen. An amplifier in your radio strengthens these radio waves, and the speaker changes them back into the original sound waves that went into the microphone in the studio.
Because radio waves travel at the speed of light, 186,282 miles per second, a listener in New York hears a program broadcast from California a fraction of a second before the audience in the broadcasting studio hears it!
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