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Weekly Activity
Our activities section suggests things for you to do with your children.
Most of these will have educational value, which we'll point out.
However, the main idea is just to have fun with them. We'll also suggest
ways you can extend them.
Visualising The Movements of the Sun, the Earth and the Moon by
Barbara Morris
Visualising the movements of the Earth, moon and sun is no more complex
than visualising the workings of a car engine. The best way to grasp it
is to recreate it yourself. You can do this by making an orrery - a
moving model of the solar system. With only two or three people, you
can make a human orrery.
You will need:
What to do
Step 1:
How the Earth spins, and the moon moves round the Earth.
One person is the planet Earth, and one is the moon.
Lay the string on the ground in a circle. This is the circuit of the
moon around the Earth.
The planet Earth stands in the middle of the 28-section circle of
string. The moon stands at any point on the string circle. The moon
moves slowly around the circle in 28 equal steps. The moon always faces
the Earth. This means the moon takes the same time to spin on its axis
as it does to go round the Earth.
The Earth always stays in the same place in the middle of the circle.
Each time the moon takes a step, the Earth spins once, turning a full
360 degrees.
Each moon-step and Earth-spin = one day of 24 hours. After 28
moon-steps and Earth-spins, the moon is back where she or he started
from. This is what makes a lunar month.
Step 2:How the Earth moves round the sun, and the moon moves round the Earth.
If you have a third person, they can be the sun. Replace the 28-section
string with the 13-section string. Each section of the string is a
lunar month. The sun stands in the middle of the circle of string. The
sun holds a non-dazzling torch or lantern. The sun does not move, but
moves the torch so that it shines at the Earth all the time. The Earth
stands at any point along the string. The moon stands close to the
Earth, facing the Earth. The Earth steps slowly round the circle in 13
steps. As the Earth takes a step, the moon shuffles sideways, making
one complete circle around the Earth. Each Earth-step and moon-rotation
represents one lunar month. Take a break between each lunar month, or
else the moon will get dizzy and feel peculiar.
After 13 steps, Earth and moon are back where they started from. 13
lunar months = 52 weeks = one year.
To be fully accurate, the Earth should spin 28 times during each lunar
month, a total of 364 times in a year. This would show how day and night
happen on different sides of the Earth, as the sun's torch lights up the
front and back of the Earth as they spin. Please don't do this 364 times.
2 or 3 times is enough to demonstrate day and night.
In fact, the Earth actually goes round the sun 364.25 times a year -
this is why we have a leap year every four years. Otherwise, our year
and the Earth's year would get out of step, and eventually we would have
Christmas in spring.
VARIATIONS
Make Earth, sun and moon celestial faces to wear. Then put on your
favourite music, and turn and spin to the music of the spheres.
If you get too dizzy, replace the people with spherical things like
footballs, globes, apples, oranges, etc, and set out your orrery on a
tabletop. Put a lamp in the middle for the sun.
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