Necessity Is the Mother of Invention
Bicycle
Mt. Tambora, a volcano in ____ exploded in 1815.
The explosion ____ a huge cloud of ash, so crops failed around the world.
As a result, people didn’t have ____ food to eat.
Surprisingly, this made traveling ____
Why? In those days, people rode ____ but many horses were killed for food.
People needed a new way to travel, and Karl von Drais invented the first bicycle in Germany ____ 1817.
Drais’s bicycle had two wooden wheels ____ no pedals.
____ did it move without pedals?
Well, riders simply pushed the ____ forward with their feet.
The ____ bicycle is the result of many inventors’ work in the 19th century.
Whiteout
Whiteout was invented by ____ Graham.
In 1956, Graham was working at a bank ____ Texas, USA.
At that time, people had to retype the whole page when they made even a small ____
Graham ____ a bad typist, so she needed a solution.
One ____ Graham saw some window painters.
When they made a mistake, they corrected it by simply painting over ____
The next day, she made her own white paint ____ used it to correct her typing mistakes.
Surprisingly, ____ noticed!
Soon, everybody at the bank began using ____
Webcam
The first webcam was invented to watch ____ coffee pot.
In 1991, Dr. ____ Stafford-Fraser and Dr. Paul Jardetzky were working at a computer lab in England.
To ____ better, they needed lots of coffee.
However, there was only one ____ machine in the building.
So, they had to make many disappointing trips ____ the empty coffee pot.
As a solution, ____ two researchers set up a camera in front of the coffee machine.
____ camera took pictures of the coffee pot three times a minute.
With special software, all the researchers in the building could see the ____ on their local network.
No more disappointing ____