HOW BROKEN BONES HEAL?

ANSWER :-

Almost immediately after the break, the body begins to try and put itself back together again. Doctors often divide the overall process into four phases:

1. When a bone breaks, the fissure also severs the blood vessels running down the length of the bone. Blood leaks out of these veins and quickly forms a clot called a fracture hematoma. This helps to stabilize the bone and keep both pieces lined up for mending. The clot also cuts off the flow of blood to the jagged bone edges. Without fresh blood, these bone cells quickly die. Swelling and inflammation follow due to the work of cells removing dead and damaged tissue. Tiny blood vessels grow into the fracture hematoma to fuel the healing process.

2. After several days, the fracture hematoma develops tougher tissue, transforming it into a soft callus. Cells called fibroblasts begin producing fibers of collagen, the major protein in bone and connective tissue. Chondroblasts then begin to produce a type of cartilage called fibrocartilage. This transforms the callus into a tougher fibrocartilaginous callus, which bridges the gap between the two pieces of bone. This callus generally lasts for about three weeks.

WHY DOES COLD TEMPERATURE AFFECTS THE BOUNCE OF THE BASKETBALL?

ANSWER:-

A basketball depends on pressurized air for its bounciness. When the ball hits the court, it compresses that air and the air stores energy in its compression. The ball's rebound is powered by the air returning to its original characteristics. The ball's skin, on the other hand, isn't all that bouncy and doesn't store energy well. To bounce well, the basketball needs to store energy in its air during the bounce, not in its skin. That's why it's important to have an air pump so that you can keep your basketball properly inflated.

WHY DOES COMBINING RED, GREEN AND BLUE LIGHT CREATE WHITE LIGHT?

ANSWER :- 

Our eyes sense color by measuring the relative brightnesses of the red, green, and blue portions of the light spectrum. When all three portions of the spectrum are present in the proper amounts, we perceive white.

The color sensing cells in our eyes are known as cone cells and they can detect only three different bands of color. One type of cone cell is sensitive to light in the red portion of the spectrum, the second type is sensitive to the green portion of the spectrum, and the third type is sensitive to the blue portion of the spectrum.

Their sensitivities overlap somewhat, so light in the yellow and orange portions of the spectrum simultaneously affects both the red sensitive cone cells and the green sensitive ones. Our brains interpret color according to which of three cone cells are being stimulated and to what extent. When both our red sensors and our green sensors are being stimulated, we perceive yellow or orange.

WHY DO EYES PRODUCE TEARS WHEN TEAR GAS IS USED?

ANSWER :-

Tear gas, in the form of CN (chlorocetophenone) or CS (chlorobenzylidemalononitrile) is often used for law enforcement. Today, CS has largely replaced CN and is probably the most widely used tear gas internationally. The tear gas is either launched in the form of grenades or aerosol cans so that the liquid becomes an aerosol.

Both CN and CS are skin irritants — they irritate mucous membranes in the eyes, nose, mouth and lungs, and cause tearing, sneezing, coughing. The more moisture on our body, the faster the acid is created and tissues are damaged, causing pain. When it is contacted with moist eyes, it affects mucous membranes which initiates glands to shed more tears.

HOW DO PEARL FORM?

ANSWER :-

Pearls are formed from pearl oysters. They are part of a group of animals belonging to the group bivalvia. This includes snails, slugs etc. Pearls are grown in live oysters far below the surface of the sea. These oysters have a hard shell covering their body. In between the shell and its body there is an empty space called the mantle.

A natural pearl begins its life as a foreign object, such as a parasite or piece of shell that accidentally lodges itself inside the mantle from where it cannot be expelled. It causes some irritation to the oyster. To ease this irritant, the oyster's body begins to secrete a smooth, hard crystalline substance around the irritant.

This substance is called `nacre'. As long as the irritant remains within its body, the oyster will continue to secrete nacre around it, layer upon layer. Over time, the irritant will be completely encased by the silky crystalline coatings. And the result is a lustrous pearl.

Nacre is composed of microscopic crystals of calcium carbonate, aligned perfectly with one another, so that light passing along the axis of one crystal is reflected and refracted by another to produce a rainbow of light and colour.

Pearls can be cultured from oysters artificially in an almost identical fashion. The only difference is that a person carefully implants the irritant in the oyster, rather than leaving it to chance. Actually we can isolate strains of oysters that possess superior pearl-producing qualities.

WHY DOES PEEPER MAKE YOU SNEEZE?

ANSWER :- 

Because the chemical piperine, an irritant, gets into the nose.
A sneeze is a reflex that is triggered when nerve endings inside the mucous membrane of the nose are stimulated.
Pepper, be it white, black, or green, contains an alkaloid of pyridine called piperine. Piperine acts as an irritant if it gets into the nose. It stimulates (or irritates) the nerve endings inside the mucous membrane. This stimulation will cause you to sneeze. Actually, the nose wants to kick out this irritant and the only way it knows how to do this is by sneezing."

WHAT'S THE DIFFERENCE BETWEEN DVD PLAYER AND BLU-RAY PLAYER?

ANSWER :-

DVD and Blu-ray™ are two types of optical storage discs, commonly used for storing movies and other video. Although the discs look similar, there are significant differences. The difference between a DVD player and a Blu-ray™ player is the laser technology that's used to record and play back the data. A Blu-ray™ player can play most DVDs; however, a DVD player cannot play Blu-ray™ discs.

DVDs

Digital Video Discs (DVDs) were developed in the 1990s, and came to market in the second half of the decade. Information is written to a DVD with a 650 nanometer (nm) red laser, which creates microscopic bumps in a groove on the disc. A DVD player contains a laser which can read the bumps in the spiral track of data. The most common type of disc can hold 4.7 GB of data.

The quality of audio and video recorded on a DVD is very high; in most cases, video is encoded in MPEG-2 format, which offers high definition, 720 pixel resolution. Surround sound options are also often available. Many DVDs also include interactive menus, additional audio tracks, and other special features.