Ancient World:
The Wheel:
• How do they work?
Wheels work by rolling along a surface. The curved surface of the wheel reduces the friction between the two surfaces due to a decrease in surface area. With less friction it is much easier to move an object. This is because rolling friction is much weaker than sliding friction.
• How did they come to be?
The wheel was invented in prehistoric times; as the oldest example of a wheel yet found is from the region of Mesopotamia (Iraq), so it may have been invented around the area where Iraq is today. The wheel may have been inspired by a simple observation of a rolling tree trunk, as the first wheels were indeed tree trunks. The next development was to use slices of these trunks joined together through an axle. Later, these wheels became wooden disks cut into a circular shape with a hole for the axle. The oldest wooden wheel archaeologists have found was built somewhere between 3350 and 3100 BC. Wheels with spokes were invented more recently, allowing people to make lighter and faster vehicles
• How do they impact society?
The biggest thing that the wheel has brought to society is the production of easier and faster transportation. It has brought us the train, the car, and many other transportation devices. Its creation aided in the discovery of another important invention, the screw. It has also aided in producing societal devices such as wheelchairs and other forms of transportation.
• How does society shape them?
The invention of the wheel was of great importance not only as a transportation device, but also for the development of technology in general, important applications including the water wheel, the cogwheel, and the spinning wheel. More modern descendants of the wheel include the propeller, the gyroscope and the turbine. The turbine is used to generate electricity.
The Horse:
• How do they work?
They are animals, and can run quickly.
• How did they come to be?