Necessity Is the Mother of Invention
Bicycle
Mt. ____ a volcano in Indonesia, exploded in 1815.
The explosion created a huge cloud ____ ash, so crops failed around the world.
As a result, people didn’t have ____ food to eat.
Surprisingly, this ____ traveling difficult.
Why? In those days, people rode horses, but many ____ were killed for food.
People needed ____ new way to travel, and Karl von Drais invented the first bicycle in Germany in 1817.
Drais’s bicycle had two wooden wheels but ____ pedals.
____ did it move without pedals?
Well, riders simply pushed the bicycle ____ with their feet.
The present-day bicycle ____ the result of many inventors’ work in the 19th century.
Whiteout
Whiteout was invented ____ Bette Graham.
In 1956, Graham ____ working at a bank in Texas, USA.
At that ____ people had to retype the whole page when they made even a small mistake.
Graham ____ a bad typist, so she needed a solution.
One day, Graham saw some ____ painters.
When they made a mistake, they corrected it by simply painting over ____
The next day, she ____ her own white paint and used it to correct her typing mistakes.
____ nobody noticed!
Soon, ____ at the bank began using it.
Webcam
____ first webcam was invented to watch a coffee pot.
____ 1991, Dr. Quentin Stafford-Fraser and Dr. Paul Jardetzky were working at a computer lab in England.
To work better, they needed lots ____ coffee.
However, there was only one ____ machine in the building.
So, they had to ____ many disappointing trips to the empty coffee pot.
As a solution, ____ two researchers set up a camera in front of the coffee machine.
The camera took pictures of the coffee pot ____ times a minute.
With special software, all the researchers ____ the building could see the pictures on their local network.
No ____ disappointing trips!