Science Arount Us !

Facts Of Science !

1: How do the glass doors automatically open when you approach them?

The sensor above the doors projects a microwave beam towards the floor. When you move into the beam, an electron signal is sent to open the doors. The doors close after the person has passed through the safety beam.

2: If you pass your finger quickly through a candle flame it would not burn you. Why? 

Although heat flows rapidly from the hot flame to your cold finger, there is not time for your finger's temperature to rise much.

3: Where do you find ball-and-socket joint in your body? 

Ball-and-socket joints at the shoulder and hip allow movement in almost any direction. The hip joint is very strong and stable and is surrounded by muscles.

4: What causes the explosive popping of a champagne cork?

Bubbles of gaseous carbon dioxide emerging from carbonated drinks cause a build-up of the pressure which pops a champagne cork.

5: Why a paper airplane arcing upward after your throw, gradually loose speed and begin to plummet downward?

As the plane's speed decreases, the pressure imbalance between the top and bottom decreases and it loses its lift.

6: When we starting walking forward what force that allows you to accelerate?

Static frictional force from the pavement allows you to accelerate and pushes you forward.

7: A common pair of pliers has its cutters located very near to the pliers' pivot. Why?

When they are near the pivot metal objects can not produce enough torque to stop the blades from rotating and they are thus cut.

8: Have you seen a spider a common resident of house spinning her web?

No. Spiders like to spin their webs in peace. A spider web is able to withstand almost anything strong, elastic and tough, the silk thread produced by spiders has many excellent qualities.

9: Sometimes the surface of a glass of water look mirrored when you observe them through the water. Explain.

Light is experienced the total internal reflection inside on the glass.

10: What is smog?

We can say that Smog is a kind of serious form of air pollution that canbcause breathing problems. Its caused mainly by vehicle exhausts and smoke from factories.

11: When you are listening to FM radio near building reception becomes bad certain locations. Explain.

It involves destructive interference in electromagnetic waves.

12: Why is water liquid?

Water is the only substance that can be solid, liquid or gas at everyday temperatures. It because of one Oxygen atom and two Hydrogen atoms. The positive electric charge of Hydrogen and negative electric charge of Oxygen attract each other and hold water molecules together.

13: What is a thermo-graphic picture?

A thermo-graphic picture is taken by a camera that senses infra-red rays. The red and orange colours show the hottest parts.

14: Where do you find the centre of mass of an empty mug?

The centre of mass of an object (empty mug) can not lie within the solid body of the object. For an empty mug it lies somewhere in the middle of the air inside.

15: Why a flame is extinguished in a vacuum?

A candle burns in a flask full of air, but when the that air is needed to support combustion. Similarly air is pumped out the flame is extinguished. It shows sound is muted in a vacuum

16: How a bird can perch on a high-voltage line without getting shock?

Current does not flow through the bird as it does not complete the circuit

17: How do you remove dust from a rug?

You cause the rug to accelerate so rapidly that it leaves the dust behind. Dust has inertia and the rapid acceleration of the rug leaves behind the dust.

18: What happens when a fast-moving pool cue hits a cue ball?

when the energy of a fast moving pool cue hit the cue ball its transfered energy to the cue ball, which accelerates instantly. Because of collision energy is transferred from one object to another.

19: Roll a sheet of paper into a tube and slip a rubber band around it. What happens when you keep a book over this vertical cylinder paper tube ?

It will hold up the book. A paper tube is a shape that has much more strength than a flat sheet. That is why pillars hold up weight in buildings.

20: Why the electromagnetic wave emitted by a radio station is coherent?

Its because the radio station's photons are similar part of a single wave.

21. As you swing back and forth on a playground swing, your apparent weight changes. At whice point do you feel the heaviest?

At the bottom of each swing.

22: A natural sea-shell when brought close to the ear, we hear an audible hissing sound. Why?

A natural sea-shell will resonate with many frequencies in the acoustic range due to its peculiar shape.

23: The Moon has no atmosphere. Suppose you throw a handful of Moon dust and a Moon rock into the sky together, which will fall faster?

Both would fall at the same rate.

24: How do whales communicate?

Whales make noise to communicate one another or locating food and finding each others with  by making eerie, low-frequency (deep-pitched) moaning noises.

25: Why do astronauts float in space?

Once in orbit, a spacecraft and the people inside it are freed from the full effects of Earth's gravity and so they feel weightless.

26: A glass-blower can shape heated glass in endless ways to create works of art. Why is not possible with normal solids such as salt?

Crystalline solids can not flow like hot glass can.

27: What is the purpose of adding detergent to the water?

The detergent lowers the surface tension of the water and the solution flows more easily than plain water.

28: How much time is spent surfing?

A 2008 survey found that users spend the most time 32.7 hours per week surfing the internet.

29: How is a slow-motion effect achieved in a movie?

When you expose film at the rate of 240 frames per second and project at the standard rate of 24 frames per second you achieve the slow-motion effect.

30: Are permanent magnets a part of your everyday life?

Yes, they are at work in electric motors, stereo speakers, telephones, televisions and even in some refrigerator doors. The earth, we live in, itself is a huge permanent magnet with its magnetic field acting between its magnetic North and South poles.

31: Why do birds build nests?

The nest plays a fundamental role in the reproduction of birds. Made against a tree trunk or in the fork of a branch, the nest, an egg shaped ball has a simple hole on the side as an entrance. The outside is constructed from twigs and lichen, with feathers, bits of string, hair and scrap of wood. But inside it is cosily lined with feathers, and furs.

32: When you throw a flying disc what causes the disc to dip sideways?

A flying disc's spin and uneven lift generate two torques or turning forces that together cause the disc to dip sideways.