Week 12 - Why does the moon change shape? 

This week we are learning about why the moon appears to change its shape during the month. Of course the moon is always a sphere, but depending on its position in relation to the Sun and Earth, different parts of it get illuminated by the Sun's light. This is why we can only see part of it in the sky at different times of its orbit.

The moon is constantly orbiting the Earth. It takes 27.8 days for it to orbit the Earth. but 29.5 days to complete a cycle of its phases which we call a lunar month. This is because the Earth is also moving as it orbits the sun, so the moon has to travel a little further than 360 degrees to get all the way round the Earth.

Please watch the video below:


We can find out which phase the moon will be on at any given day of the month by using a moon phases calendar. Below is a link to a website which has a calendar of moon phases. Click on it and have a go at working out what the moon's phase will be on your birthday this year.

www.moonconnection.com/moon_phases_calendar.phtml


Here is a diagram showing the eight phases of the moon.


Here is a video to watch:

It takes our Moon about 28 days to completely cycle through all eight phases. Occasionally (about every 2.7 years) there are two Full Moons in the same month. This is referred to as a Blue Moon. Hence the saying "Once in a Blue Moon".

New Moon

The side of the moon facing the Earth is not illuminated. Additionally, the moon is up through out the day, and down through out the night. For these reasons we can not see the moon during this phase.

Waxing Crescent

During this phase, part of the Moon is beginning to show. This lunar sliver can be seen each evening for a few minutes just after sunset. We say that the Moon is "waxing" because each night a little bit more is visible for a little bit longer.

First Quarter

During first quarter, 1/2 of the moon is visible for the first half of the evening, and then goes down, leaving the sky very dark.

Waxing Gibbous

When most of the Moon is visible we say it is a Gibbous Moon. Observers can see all but a little sliver of the moon. During this phase, the Moon remains in the sky most of the night.

Full Moon

When we can observe the entire face of the moon, we call it a Full Moon. A full moon will rise just as the evening begins, and will set about the time morning is ushered in.

Waning Gibbous

Like the Waxing Gibbous Moon, during this phase, we can see all but a sliver of the Moon. The difference is that instead of seeing more of the Moon each night, we begin to see less and less of the Moon each night. This is what the word "waning" means.

Last Quarter

During a Last Quarter Moon we can see exactly 1/2 of the Moon's lighted surface.

Waning Crescent

Finally, during a Waning Crescent Moon, observers on Earth can only see a small sliver of the Moon, and only just before morning. Each night less of the Moon is visible for less time.

Task: Cut out the pictures in the sheet below, arrange them in the order that they appear during a lunar month, starting with the new moon. Please label each one. You can use the diagram further up the page to help you. I have set an assignment on Teams for you to send it to me.

Homework:  Go onto this link and write a paragraph of moon facts. www.primaryhomeworkhelp.co.uk/moon/phases.html