Moon Phases Demonstration


hi my name is emily morgan and i'm the

author of next time you see the moon

from NSTA kids and i'd like to share a

simple activity with you that can help

you understand why the moon looks

different at different times throughout

the month why sometimes it looks like a

banana and other times it looks like

half of a circle and other times it

looks like a big round ball well do this

activity you only need four simple

things you need a lamp with the shade

removed a white foam ball a pencil and a

darkroom the darker the room the better

now in this model the lamp is going to

represent the Sun and of course the

white foam ball is going to represent

the moon and your head is going to

represent the earth so let me show you

how this works we know that the moon

orbits the earth so in this model I'm

going to get the moon the foam ball to

orbit the earth my head notice that no

matter where the moon is in its orbit

half of it is always lit up by the Sun

but when in the moon is in this position

I can't see any of the lighted side of

the moon from Earth my head from this

angle you can see what I am seeing from

Earth we call this new moon when it's

new moon we look up at the sky and we

can't see the moon it's there but the

side that's reflecting sunlight is away

from us now as I slowly make the moon

orbit to my left I can begin to see a

tiny sliver of that lighted side we call

that a crescent moon as the moon keeps

orbiting we can see more and more of

that lighted side we see half of the

lighted half which is a quarter moon in

this case a first quarter moon as we

keep orbiting we see almost the whole

lighted side we call that a gibbous moon

then when we can see the entire light at

half of the moon that's a full moon as

the moon continues in its orbit we begin

to see less and less of that lighted

side we're back to a gibbous moon but

this time the light is on the opposite


then another quarter moon last quarter

moon to be exact


another crescent and finally back to new

moon and the cycle begins again


so why does the moon appear in different

shapes throughout the month because of

its orbit the shape or phase of the moon

depends on where it is in its orbit

around Earth it takes about a month for

the moon to orbit the Earth so when you

look up at the moon today know that

you'll see that same phase again about a

month from now thank you for watching

and I hope you give this activity a try

and I hope that you have a sense of

wonder next time you see the moon or a

full description of this activity and

other resources for teaching about moon

phases go to WWN sta org slash next time

- moon there our moon calendars and

other science and reading activities

there for more information about the

next time you see book series visit