Why the moon appears to have different phases?

Answer 1

Because of its position relative to Earth and the Sun.

The Moon orbits the Earth once every 29 days.

Starting with day 1. It is a NEW Moon . Its position is in a plane between Earth and Sun. We do NOT see a New Moon, because the Sun's Light over powers it, except when that plane the Moon in , becomes a direct line between Earth Moon & Sun; then it is a Solar Eclipse.

From day 2 to 7 the Moon is moving away from the Sun's plane, so we begin to see it . During this period is a WAXING CRESCENT Moon and seen in the evening, shortly after Sunset.

At day 7 the Moon is at a right angle(90 degrees) between Earth & Sun, So we see it as a half circle , known as FIRST QUARTER ( Because it has gone a Quarter way around its orbit of Earth).

From day 8 to 14 the Moon is moving away from the Sun's plane, so we begin to see it . During this period is a WAXING GIBBOUS Moon and seen in the early night.

At day 14 or 15 the Moon is at a plane (180 degrees) This plane is Sun, Earth and Moon. So we see it as a full circle , known as FULL MOON ( Because it has gone a half way around its orbit of Earth). At this point , if the Sun Earth and Moon are in a staight line , we see a LUNAR Eclipse. The Moon is far less bright and appears as a dull red or grey colour, due to Earth's reflected light.

From day 15 to 21 the Moon is moving towards the Sun's plane, so we begin to see it . During this period is a WANING GIBBOUS Moon and seen in the late night.

At day 21 the Moon is at a right angle(90 degrees) between Earth & Sun, , but on the opposite side of the Earth. So we see it as a half circle , However, the circle is the opposite way around to the first quarter. , known as LAST QUARTER ( Because it has gone a Three Quarter way around its orbit of Earth).

From day 22 to 28 the Moon is moving towards the Sun's plane, so we begin to see it . During this period is a WANING CRESCENT Moon and seen in the early morning before sunrise.

Day 29 or 1. It is a NEW Moon . Its position is in a plane between Earth and Sun. We do NOT see a New Moon, because the Sun's Light over powers it, except when that plane the Moon in , becomes a direct line between Earth Moon & Sun; then it is a Solar Eclipse. And the process is repeated.

As an experiment , Din a darkened room, with a pin-hole of bright light, two balls, one larger than the other.

• The pin-hole of light is the Sun , The larger ball is the Earth , and the smaller is the Moon. Place the Moon(ball) between Earth(Ball) and Sun (pin hole) and look at it from behind the Earth. . Then move the Moon to a right angled postion and loo at it from the opposite side of the Earth. . Similarly for a stright line , Sun, Earth and Moon , and finally at the opposite side of the Earth. If done well then you should see the Moon (ball) its its different phases(shadows).
• Hope that helps!!!!!

Answer 2

the sun casts shadows on the moon which makes it appear to look different.