Physics

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• Physics
• Project

Daily life
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Content

• Introduction
• Optics- mirage
• - magnifying glass
• Electricity magnetism- Trees and thunderstorm
• -
  lighting conductor
• Mechanics- talk in Space
• - explosion
• Heat- cooking
• - clothing of people in desert
• Conclusion
• Sources

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Introduction

• With the advances in technology, we are
  surrounded by machines and inventions. The laws
  and concepts of physics help us to fully
  understand our world and to make use of the
  machines and inventions.
• Physics is the branch of science in which the
  behaviours of objects and energy are studied.
  Physicists study the laws of nature
  quantitatively. They collect facts from
  observations and data from experiments.
• Therefore, natural phenomena in our daily life
  should be relate to physics. And we do this
  project to investigate the rationale behind some
  daily natural phenomena.

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Optics-Mirage
In hot place such as a desert, air
layers are hot near the ground. Higher up the air
layers become gradually cooler and optically
denser. Light from the sky is constantly
refracted away from the normal as it approaches
the ground.
When the angle of incidence is larger than
the critical angle at some layer, total internal
reflection occurs. The reflection of the sky
appears as a pool of water. This is called a
mirage.
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Magnifying glass
A magnifying glass is a convex lens of
short focal length. It is used to produce an
enlarged and upright image. The object to be
viewed is placed within the principal focus of
the lens.
The image is virtual, erect and
magnified. To obtain the largest image on the
retina, the object position is adjusted so that
virtual image is at the near point of the eye.
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Electricity magnetism- Trees and thunderstorm
QWhy should we avoid standing under trees when
there is thunderstorm? Ans.A wet tree is a good
electric conductor. When there is thunderstorm,
charges jump from the cloud to the tree, it is
thus dangerous and easy to get strike when
standing under the tree.
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lighting conductor
QHow does lighting conductor work? Ans.Lighting
conductor is a sharp-tipped metal rod fitted at
the highest point on tall buildings, which
connects to the ground by wire. Due to point
action, charges induced may accumulate on the
lighting conductor, less charges are thus induced
on the roof. Therefore, it is less likely that
the building will be struck by lighting.
If the building is struck by lighting, most of
the electrons are attracted to the lighting
conductor and they pass down to earth though the
wires. The damages on the building can then be
minimized.
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Mechanics- talk in Space
QHow can astronauts

communicate in the Space?
Ans. Space is
essentially vacuum that no transmitter and
receiver emitting and receiving electromagnetic
waves can be used for communication.
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explosion
Q When explosion occurs far away, why do we
sense the vibration of the ground before hearing
the sound?
Ans. Sound waves travels at different speeds in
different mediums. It generally travels faster in
solid than in air. Therefore, we sense the
vibration of the ground before the sound of
explosion is heard.
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Heat-cooking
Q Why hot oil splashes out when some drops of
water are added?.
Ans. When small amount of water contacts with
hot oil, it vaporises to steam immediately, and
its volume increases tremendously. This rapidly
expanded steam causes the hot oil to splash out
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clothing of people in desert
People in desert wrap bright blankets
around them under sunlight to reflect heat
radiation, preventing sunstroke.
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Conclusion
The relationship between physics and
our everyday life cannot be separate. From the
alarm clock wake up you in the morning, transport
u take to school, elevator you take while u go to
lunch and etc.
If we keep an eye on every little matter
around us and always think of the rationale
behind them, we may become the next Newton!
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Sources

• Mastering physics 1 For New Certificate Syllabus
  (2nd edition)
• Mastering physics 2 For New Certificate Syllabus
  (2nd edition)
• http//www.hk-phy.org

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The end
by 6B (2)Au Pui-chi, Paggi