Telephone
Alexander Graham Bell invented the telephone in 1875.He found that he could send messages along a write using electricity.

Who invented the world wide web

(Www)?
Tim Berners-Lee,a British Computer Scientist, developed the World Wide Web in 1990
The WWW is a system of Computer files linked together on the Internet creating a Source Of multimedia information,that includes illustrations, sounds, and moving pictures in addition to text.The introd

uction of the Web helped make the Internet popular and easier to use.

Who invented the Braille
System of printing and writing
For the blind?
Louis Braille (1809-1852) Was a blind student Of 15 years when he invented the system of printing and writing for the blind.Braille is made up of raised donts.Words are indentified by running one’s fingertips over the dots.In 1929,Louis Braille published this dot system.

Who introduced
‘’Heliocentric Theory’’ of our
Solar system?
Nicholas Copernicus (1473-1543),the Polish astronomer.During his time scientist believed that the Earth was fixed at the centre of the universe While the sun,the moon and other planets rotated around it.If was Copernicus Who stated, all the planets inculuding the Earth orbit the sun,and showed how this new system could accurately calculate the positions of the planets.

How did Dinosaurs become
extinct?One of the major extinction theories claims that a large asteroid hit the Earth’s surface throwing billions of tons of dust and debris into the atmosophere.Heat from the impact caused huge fires While clouds of smoke and debris blocked sunlight from reaching the surface of earth for many months.soon,the lack of vegetation and thesubsequent drop in land temperature made it impossible for dinosaurs to survive

How does a ship made of
Steel stay afloat?
A steel ship floats because us its hull displaces a Weight of water that is equal to its own weight.This causes an up-thrust,a force that pushes the hull upwards and keeps the ship afloat.