why earth is round in shape?

Question

why earth is round in shape

Answer 1

1) Gravity and the rotation of the Earth.

2) A basic roundish shape when it BANGed into existence.

3) Earth isn't perfectly round. It's actually a bit bigger around the equator than it is when measured from pole to pole.

Answer 2

Hi,

Hope You and family are fine.



Shape of the Earth
--------------------------------------------------------------------------------


From the time we enter kindergarten we are told that the Earth is round, yet there is very little in our day-to-day experiences to tell us that this is true. Even from an airplane flying at normal commercial aircraft altitudes (35 to 45 thousand feet) the Earth appears as flat as a pancake with rivers, valleys, and mountains breaking its flatness. Today, we have little reason to doubt that the Earth is a sphere. We have seen photographs that have been taken from artificial satellites in orbit around the Earth and the Moon.

People knew the Earth was spherical over 2,500 years ago. This was concluded from observations of the Sun and Moon. The Greek philosopher Pythagoras concluded in 500 B.C., that the Earth must be round because the Sun and Moon are round. Two hundred years later the philosopher Aristotle taught his students that the Earth had to be round because the shadow of the Earth falling on the Moon during a lunar eclipse is always circular. Aristotle reasoned that the only solid body that consistently gives a circular shadow is a sphere. Therefore, the Earth must have a spherical shape.

These conclusions were supported by observant travelers over both land and sea. Sojourners noted that certain bright stars in the northern sky appeared higher in the sky the farther north they traveled while stars in the southern sky disappeared below the horizon. The opposite occurred as they traveled southward. This can only happen if one is traveling over a circular surface.

Years of collecting evidence to verify the Earth's spherical nature finally allowed scientists to show that the Earth is not a true sphere, but rather an oblate spheroid. An oblate spheroid is a sphere that bulges at the equator and is flattened at the poles. This was proven by an expedition to measure accurately one degree of latitude at various distances from the equator to the North Pole. These scientists showed that the land distance of one degree latitude at the equator is equal to 110.813 kilometers (68.704 miles). The same one degree of latitude near the North Pole is equal to 111.947 kilometers (69.407 miles). If the Earth were a perfect sphere these distances would be the same at all places on Earth.


PROOF THAT THE EARTH IS SPHERICAL
--------------------------------------------------------------------------------
OBJECTIVE:

To use indirect evidence as a means of verifying that the earth is a spherical body in space.

MATERIALS:

a cube, such as a child's building block
a rectangular block of wood or other ridgid material
a cylinder such as a can of soup
a cone such as the sugar cones used for ice cream
a tennis ball (or any other kind of ball)
a slide, filmstrip, or overhead projector
a projection screen or light colored wall


--------------------------------------------------------------------------------
INTRODUCTION:

Cosmologies from widely separated ancient cultures often had a description of the Earth and its general place in the scheme of the universe. These descriptions usually made the Earth flat or at best only slightly curved. By 500 B.C., however, the observational data clearly showed that a flat Earth was not a reasonable model. If the Sun and Moon are round, then the Earth must be round, too. Sailors and other travelers reported that certain bright stars appeared higher or lower in the sky as one traveled northward or southward across the Earth. This can only happen if the travels are made on a curved surface. As ships sailed out to sea it was observed that they did not disappear by growing smaller, but rather disappeared as if they were sinking into the ocean - first the keel disappears, then the lower part of the sail, then the "crow's nest" or mast tips. Again this can only happen if the ships are sailing over a curved surface.

The Greek philosopher Aristotle (ca. 384-322 B.C.) used the arguments cited above plus one more. Aristotle concluded the Earth must be spherical because of the shape of the darkened shadow of Earth that moves across the face of the Moon during lunar eclipses. By this time period it was fairly well accepted that eclipses of the Moon occurred because the Earth was blocking the Sun's light from the Moon. No one had ever reported the shadow of the Earth that falls on the Moon to be any other shape than circular. Aristotle argued that the only geometric solid that could always give a circular shadow, no matter how it was oriented in space, was a sphere.

This activity will allow experimentation with common shapes to determine if Aristotle was correct.

PROCEDURES:

1. Set up the projector and screen so that the various objects can be placed in the light beam and shadows will be cast onto the screen. (An alternative might be to take the students outside on a sunny day and let them watch the shadows of the objects on the ground or sidewalk.)

2. Place the child's block in the light beam and observe the shadows cast by it. Turn the block in as many ways as is possible to see how the shadow changes with orientation of the solid. Under a column labeled for each of the solid shapes with which you are experimenting, draw a picture for each different shadow or describe each different shadow seen as completely as possible.

3. Repeat the above step with each of the other solids and record your observations in the same manner as in Step 2.


Hope this helps.

Take care,

Warm Regards,

Tanvir.

Answer 3

The earth is not round, it's oval, haven't you seen the world map?
Just kidding, the earth is round because of the forces of gravity holding it together.

Answer 4

It's got something to do with gravity spinning it around in a speherical manner. It's kind of like erosion, like when you rub a pebble for years and years it eventually goes smooth.

Answer 5

It's a planet. Planets are supposed to be round.

Answer 6

the earth isnt round...

Answer 7

because GOD has made it round that's y

Answer 8

it was made by GOD we cant say ant thing he can do wht he wants

Answer 9

because there is other planets lol, Susie