Do You Know
Questions & Answers on General Knowledge.
How does a sound dish work? I know that it's a parabola, but I can only find drawings not explanations.
A sound dish is actually a mirror telescope for sound. When sound waves from a distant source encounter a rigid parabolic surface, they reflect in such a way that they focus to a point. If you put a microphone at that point, it will detect the sound waves from the distant source. You can see this focusing effect by drawing a parabola on a sheet of paper and directing parallel lines—the sound waves from the distant source—toward the parabola. If you reflect each line in a mirror-like fashion from the surface it hits, you'll find that all the reflected lines pass through a single point as they move away from the parabola.
What happens to ice when it is left in the freezer? does it evaporate? I have noticed that over time the ice cubes shrink?
What is the difference between a magnet and an electromagnet? Why are some metals automatically magnetic?
What is an abacus, and how long has it been used?
What was the Silk Route?
How are tunnels built?
What happens to gas in a gas mask?
Is it true that at one time there was no oxygen?
Is a CB radio also an AM radio?
Why do we say “Hello” when we answer the telephone?
Why do whales have holes on their heads?
What kind of stars are binary stars?
Is it true that gravity is stronger at the north pole than at the equator. Does that mean that a person would be able to jump higher at the equator?
Which is the highest mountain peak in the world?
Which states are the biggest farm states?
Why do scantron-type tests only read #2 pencils? Can other pencils work?
How does a paper airplane fly?
Which types of computers predated Babbage’s "analytical engine"?
What causes "growing pains"?
Where in the world do people live the longest?
In cooking, what are some examples of absorbing microwaves, transferring microwaves, and reflecting microwaves?
What is a shockwave and a sonic boom?
Is that a crocodile or an alligator?
What is a season?
How far did the British Empire reach?
Where is the wettest place in the world?
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Dos Don ts about the diet
1. Diet should be low in fat, protein and salt. w Avoid milk & buttermilk.
2. Avoid coffee, tea, alcohol, smoking & processed foods.
3. Weight reduction is mandatory for overweight people.
4. Take plenty of citrus fruits, fruit juices, fruits, vegetables & salads.
5. A golden rule: To be followed religiously with all types of treatments - exercise the affected joint every day. The exercise goes a long way in helping movement, mobility of the joint and also in reducing pain.