Brrr! Whose idea was it to camp in winter?
And why is winter
so much colder and darker than summer?
To understand this, we need to explain how
the tilt of the Earth's axis
affects the amount of sunshine we get,
and explain how the tilt of
the Earth's axis affects
how warm the sun feels.
The Earth spins on its axis.
The fact that it takes 24 hours to complete
one spin helps us explain day and night.
But it is the tilt of
the Earth's axis that will
help us understand the seasons.
It is tilted at an angle of 23.4 degrees,
and the Earth takes
one year to orbit the sun.
Different parts of the Earth are
tilted towards the sun as it orbits.
In winter, the northern hemisphere
is tilted away from the sun.
This means fewer hours each
day are spent in daylight.
In summer, the northern hemisphere
is tilted towards the sun.
This means more hours
each day are spent in daylight.
The tilt of the Earth
also affects the angle that
the sun shines onto
different parts of the Earth.
In the summer, the sun is
shining more directly
at the northern hemisphere.
In the winter, the sun
shines at more of an angle.
The sun appears higher in the sky in
summer and lower in the winter.
The angle of the sun in the winter spreads
the sun's rays over a larger area.
They are less concentrated,
and so it feels colder.
So, the Earth's tilt really does mean
it's better to go camping in
the UK in summer.
In winter, the Northern hemisphere
is tilted away from the sun.
We have fewer hours of daylight,
and the sun's rays are spread over
a larger area, meaning it's colder.
In summer, the northern hemisphere
is tilted towards the sun.
We have more hours of daylight and the sun
shines more directly onto
us, meaning it's warmer.
I know which one I prefer.
[bird song]