Download Earth`s Shape and Size - Hicksville Public Schools / Homepage

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
Transcript
Earth’s Shape and Size
Unit 1
The Earth’s Shape
• Earth’s shape is
nearly spherical
(Oblate Spheroid)
• It is flattened at
the poles and bulging
at the equator
• This makes a person
weigh slightly more
at the poles than at
the equator
• Earth’s surface is
very smooth
• The height of Mt.
Everest is only
7/10,000 of Earth’s
diameter
Ancient Observations of Earth
• Shadow of Earth during an eclipse
• Position of the stars as travelers moved
north or south
• A ship’s mast disappeared last as it
sailed towards the horizon
• Aristotle, as early as the 3rd century BC
concluded that the earth was a sphere.
Using the North Star
• The North Star (Polaris) appears to
increase in altitude as you travel north
• It is always visible due north to an
observer north of the equator
– 900 for someone at the North Pole
– 00 for someone at the Equator
• If the earth were flat, Polaris would
appear the same to everyone.
Today….
• Photographs from
space are the best
way to see the shape
of the earth
Other proof that the earth is
round/spherical
Pre Lab Info
• Roundness Ratio
– Tells us how close something is to a perfect
circle
– A perfect circle would have a roundness
ration of 1 because the diameter would be
the same in all directions
Pre Lab Info
• Scale Models are concrete
representations of an object that is
made in proportion to the object
– They may be larger (ex. Model of an atom)
– They may be smaller (ex. Globe)
Finding the Proportions
• Think ratio: Part to whole = Part to
whole
• Matchbox cars are made on a ratio of
1:59
• This means that the Matchbox car is 59
times smaller than the real car.
• Using the Matchbox car, figure out how
big the real car is.
• 1/59 = 7.1/X
7.1 cm
• X = 418.9 cm
• How many meters is
this?
• 4.189 m