How do seasons happen

7/27/2019 How do seasons happen

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How do seasons happen?

Seasons come to us regularly. We have probably noticed that it gets warmer in summer or dry season

while it get colder in the winter or wet season. However do we know how these seasons change?

Seasons happen and change every year. This happens because the earth tilts back and forth as it goes

around the sun. During the summer, the earth tilts toward the sun. It makes half of the earth hotter. this

condition is what we call summer. During the other half of the year, the earth tilts away from the sun. As a

result, it makes that half of the earth cooler. This cool condition is then what we call winter.

The different parts of the world have the same season at different times. In the northern half of the world ,

winter happens during the months of December, January and February. The regions are such North

America and Europe. In the other hand, the southern half of the world have winter during the months of

June, July and August.The regions are like South America and Australia. How does this difference

happen? The same season happens at different times because the top and bottom halves of the earth tilt

away from the sun at different times.

Source: kidscientist.com/5/why-do-seasons-happen

Why do the seasons happen?The Earth rotates around the Sun and takes one year to complete one full rotation.

The earth has a Northern hemisphere and a Southern hemisphere with the Equator round the

middle. The Equator transits the Ecliptic twice a year, once in March and the other in September.

It also has the Tropic of Capricorn in the Southern hemisphere and the Tropic of Cancer in the

Northern hemisphere. Each of these are positioned 23.5 degrees from the Equator and represent

the extremes of the motion of the Sun as it appears to stop and change direction.

The Earth rotates around the Sun at an angle of 66.5 degrees relative to the ecliptic and it is this

which causes the seasons over the twelve month period. (90-23.5 = 66.5)

When the Northern hemisphere is tilted away from the sun this is Winter in the Northern

hemisphere because the Sun's rays are less concentrated (more spread out) and the Sun is

lower in the sky.

At the same time when the Southern hemisphere is tilted towards the Sun the Sun's rays are

more concentrated and the Sun is higher in the sky - this would be Summer in the Southernhemisphere and this is how it happens....hope this works ̂ ^~ The Reason f o r t he Seasons

Many people think that some parts of the year are hotter because we're nearer to

the Sun, but the real reason is that the Earth is wonky (tilted).

W h y d o w e h a v e s e a s o n s ?

We have seasons because the earth is tilted (wonky) as it makes its yearly journey

around the sun.



The Earth's tilt

The Earth's axis is tilted at an angle of 23.5 degrees. This means that the Earth is always "pointing" to one

side as it goes around the Sun. So, sometimes the Sun is in the direction that the Earth is pointing, but not at

other times. The varying amounts of sunlight around the Earth during the year, creates the seasons.

The tilt of the Earth's AXIS is the most important reason why seasons occur.

We have hot summers and cold winters because of the tilt of the Earth's axis.

The tilt of the Earth means the Earth will lean towards the Sun (Summer) or lean away from the Sun (Winter)

6 months later. In between these, Spring and Autumn will occur.

I m p o r t a n t F a c t s

The Earth revolves around the Sun.

The North pole always points the same way as the Earth revolves around the Sun.

The Earth's movement around the sun causes the seasons.

D u r i n g a Y e a r

The Earth takes 365.24 days to orbit the sun. As we move around the Sun during the year, the amount of light

each area of the planet receives varies in length.

When the Earth's axis points towards the Sun, it is summer for that hemisphere. When the Earth's axis points

away, winter can be expected.

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T h e n o r t h p o l e t i l t s t o w a r d s t h e s u n

It is Summer time in countries in the Northern Hemisphere.

It is Winter time in countries in the Southern Hemisphere.

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T h e n o r t h p o l e t i l t s a w a y f r o m t h e s u n

It is Winter time in countries in the Northern Hemisphere.

It is Summer time in countries in the Southern Hemisphere.

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Since the tilt of the axis is 23 1/2 degrees, the north pole never points directly at the Sun.

A u t u m n

The north pole begins to move away from the Sun. The Sun rises lower in the sky so the days start getting

shorter. When the Sun is at its mid-point in the sky, we reach the 'autumn equinox', around 22 September.

Day and night are both 12 hours long and its the beginning of autumn.

S p r i n g

The Earth continues on its path, and our north pole starts moving towards the Sun again. The Sun moves

upwards in our skies and the days continue getting longer. Again, we reach a midpoint when day and night are

both 12 hours long. This is called the 'vernal (or spring) equinox' and happens around 21 March.

D i d y o u k n o w ?

The Earth's movement around the sun causes the seasons, but it does not affect the temperatures during the

seasons.

Many people believe that the temperature changes because the Earth is closer to the sun in summer and

farther from the sun in winter. In fact, the Earth is farthest from the sun in July and is closest to the sun at the

beginning of January!

T h e h e i g h t o f t h e s u n i n t h e s k y v a r i e s w i t h t h e

s e a s o n s .

The sun is at its heighest at 12:00pm (noon) on any gven day.

In the summer the sun is higher than it is in the other three seasons.

http://resources.woodlands-junior.kent.sch.uk/time/equinox.html










Summer

During the summer, the sun's rays hit the Earthat a steep angle because the sun is higher inthe sky. The light does not spread out verymuch, thus increasing the amount of energy

hitting any given spot. The long daylight hoursduring the summer months allow the Earthplenty of time to reach warm temperatures.This is why the days are hotter in the summermonths.

Because the sun is higher in the sky ourshadows are shorter than they are in the theother three seasons.

W i n t e r

During the winter, the sun's rays hit the Earthat a shallow angle because the sun is lower inthe sky. These rays are more spread out, whichminimizes the amount of energy that hits anygiven spot. The long nights and short daysprevent the Earth from warming up. This is whywe have cold winters.

T h e L e n g t h o f t h e d a y a n d n i g h t v a r i e s t h r o u g h o u t t h e

y e a r

Summer Months

Summer is warmer and winter is colder because of the length of our days and nights.

In the summer daylight lasts longer and night time is shorter.

Winter Months

In winter the days are shorter and the nights longer.There is more time for the sun to warm us during long

summer days. And short winter days have long, cold nights.

T h e t h r e e r e a s o n s w h y w e h a v e S e a s o n s

1. Tilt2. Revolution - The Earth revolves around the Sun.



3. The North Pole always POINTS in the Same Direction

How do seasons happen

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