Titanic

Do you know it took three years to the build titanic, and the cost was $7,500,000. There were 2201 passengers on board and only 20 lifeboats, which is only enough for half of the passengers in the ship. Titanic carried 3560 life jackets but it dint help all the passengers to survive. Mails of 3000 bags were also present in the ship. Most of the passengers survived after the terrible accident is first class passengers those who were charged $4,350 for the ticket. The cost of the second class is $1750 and $30 for the third class. It is usual to break champagne bottle in the bow of a new ship but that was not happened when titanic started its voyage. Titanic consumed 825 tons of coal every day. The speed of titanic is 23 knots.

Hummingbirds

Among all birds Hummingbirds are the smallest. The interesting fact about the hummingbird is they flap their wings 11-90 times per second. Hummingbirds can fly in the speed of 54 km/h. These birds need lot of energy to fly as their heart beats 1,260 times per minute. So they visit 1000 of flowers every day, they also eat smal insects. The hummingbirds brain weight is 4.2% of it whole body weight, that is the largest, when compared with the bird kingdom. These are the only species which can fly backwards which no other birds can do. On an average a hummingbird live for 3 to 5 years. Even though many hummingbirds die in one year at the time of leaving the nest.

Working of DC motor

Motors converts electrical energy to produces mechanical energy. When current passes in a wire and is placed in region of magnetic field the wire will get force. The size of force tells how fast the motor spins. Force depends on the current in the wire, wires length and the strength of the magnetic field.
(Force = current * wires length * magnetic field)
DC motor contains two magnets and a coil is placed in the middle of the magnets. When current passes through the coil it produces a magnetic field. The repletion and attraction of the magnet gives torque by which the armature turns.