Science 8: Unit E: Mechanical Systems

1
Science 8 Unit E Mechanical Systems

• Topic 8 People and Machines

2
Technology Changes to Meet Changing Needs

• Technology changes as human needs changes.
• Technology also changes as science, materials and
  other technologies change and improve.
• Eg. the discovery of gunpowder made the
  technology of cannonry a reality.
• Finally, technology changes and improves through
  trial and error.

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Technology Changes as Needs Changes

• As the Industrial Revolution picked up steam
  during the 1800s humans discovered that their
  needs were changing.
• Instead of living spread out in the country,
  people were now living in cramped cities with
  millions of other people. Moving around in the
  city was becoming a major problem.
• Subway London 1863 With space limited, the
  British govt created the first underground rapid
  train to help move workers around London.

4
Technology Changes as Science Changes

• 1905 Einstein discovers and describes the
  photoelectric effect that light can be used to
  excite electrons form electricity.
• Since the PV Effect was discovered, everything
  from solar calculators to solar powered cars and
  homes have been created.

5
Technology Changes as Materials and other
Technologies Change

• Example 1 The invention of a cement chemical by
  the Romans led to the creation of the first
  arches which then were used to help support large
  structures such as the aqueducts.
• Example 2 The invention of the Internal
  Combustion Engine led to everything from city
  planning based on the car to the invention of the
  airplane.

6
Technology Changes through Trial And Error

• Without understanding the science behind
  eyeglasses, Italian opticians designed primitive
  eyeglasses for wealthy noble people since the
  1200s.
• Optics and refraction wasnt understood till
  Newton came along in the early 1700s, so for
  nearly 500 years, trial and error was used to
  create reading glasses.

7
How Technology Changes Science

• We know that science helps technology change and
  improve, but oftentimes technology changes and
  improves science.
• The invention of the magnifying lens and
  refracting telescope allowed Galileo and
  Copernicus to help improve scientific knowledge
  of the solar system. (ie. They discovered that
  the sun is the centre, not the Earth)

8
Terms to Know

• Ergonomics The science of human comfort.
• Hydrogen Fuel Cell A cell which uses hydrogen
  and oxygen gases and reacts them to produce
  electricity. The only waste product is water
  vapour (along with the waste energy).
• Mass Production The use of assembly line work,
  robots, etc. to produce many copies of identical
  products.