Sun & Moon

[flixxchick]

Why can you sometimes see the moon and sun in the sky at the same time? Always wanted to know this.

[kags]

(part 1)
The moon is orbiting the earth every 29 days - at one point in its orbit, it will be directly in front of the sun, so we will not see it at all for a couple of days. It will then emerge as a new moon, and will rise just after the sun, rising later each day and becoming bigger as it reflects more of the sun's light. It starts to become noticeable in the afternoon and evening sky.

[kags]

(part 2)
Around 14 days later, it will be exactly opposite the sun, so we will see it as a full moon, reflecting maximum light from the sun. At this point it rises at the same time as the sun sets, so we only see a full moon at night. As the moon wanes, it rises later in the night, and will still be visible in the mornings

[mibn2cweus]

Since the Moon's orbit around the Earth lies roughly on the same plane as the Earth's orbit around the Sun these can be illustrated on a flat sheet of paper.

Try drawing a small (1" or 3cm) circle in the center of a sheet of paper to designate the Sun.
Draw a large circle with the Sun at its center (a bit smaller than the width of the paper) to show the Earth's orbit around the Sun.
Draw a smaller circle (1/2" or 2cm) on the large circle you just drew to designate the Earth at some point in its orbit around the Sun. Shade the half of the Earth that is opposite the Sun.
Now draw a circle (2" or 5 cm) around the Earth to show the Moon's orbit around the Earth.

Using this as a template draw a small circle (1/4" or 1cm) on the Moon's orbit to show a possible position for the Moon and shade the half opposite the Sun.
Imagine how the Moon as illustrated in your drawing would appear from daytime (unshaded) and nighttime (shaded) places of the Earth's surface. Do the same for other positions of the Moon's orbit around the Earth.

Some times the Moon will be behind the Earth and so cannot be seen from half of the Earth's surface.

I hope this was fun but if you don't have paper and pencil look here.