Why does water put out fire?

There is a fire triangle made up of

heat, fuel and oxygen. For a normal fire to

burn, all these elements have to be present.

If any of these is absent, fire will not occur.

This is where water plays the trick.

Water puts out fire in two ways.

When we spray water on fire, it takes some

heat away from the fire and gets itself

evaporated. When water takes away heat,

the temperature thus falls below the levels

of burning. So, fire goes out. If we use a lot

of water, fire is extinguished by cutting off

the oxygen supply too. Here, water acts as a

layer between air and fire.

But, we can’t use water for dousing

all type of fire. Don’t apply water to such

types of fire as electrical fire and oil fire.

Why does an electric bulb make a

bang when it is broken?

This sound is produced by the air

surrounding the bulb. The inside of an

electric bulb is vacuum. So, the pressure

inside is lower than that of the outer

atmosphere. When the bulb is broken, air

rushes in at high speed from all sides to fill

up the vacuum. The sudden surge of air

produces a bang.

An electric bulb produces light when

its filament is heated at a high temperature.

The vacuum inside the bulb prevents the

filament from oxidizing with air.

Why is space shuttle different from

a rocket?

The term rocket generally refers to a

medium that carries such objects as

satellites, space probes etc., into space. But

they never go into orbit. The fuel burnt

inside a rocket produces high –energy

gases. These gases emitted through the

rocket’s tail push it upwards into the sky.

Different rockets can reach different

altitudes in the sky, and they are generally

not reusable.

On the other hand, space shuttle is a

partially reusable space vehicle that can

carry astronauts and large objects well into

space. To reach its destination, a space

shuttle needs the help of booster rockets.

Space shuttles are limited to low-Earth

orbits.