Modeling Moon Phases and Eclipses

DSVS Spring 2011Sixth Grade

Lab 2

Background Info

Discussion• Ask, what do you know about the moon?• Does the moon stay still in the sky?

– No, the moon orbits the earth, just like the earth orbits the sun.– Because the moon rotates around the earth, its position in the sky changes

continuously.• The moon does not provide its own light source; the only reason we can see it

is due to sunlight reflecting off the surface of the moon.• The moon, like the sun, rises from the eastern horizon and sets towards the

western horizon. • Each morning, the moon moves closer to the sun• As the moon moves closer to the sun, its shape appears thinner• The lighted portion of the moon is always on the side facing the sun.• What is a solar eclipse?

– solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially covers the Sun

Discussion• Ask: Ever noticed that the moon sometimes

looks different in the sky? How does it look? What are these phases called?– Full, gibbous, half or quarter, crescent, new

• How long does it take for the moon to go through one cycle of change from new moon to new moon? – Around 29.5 days

• What is waxing, what is waning?– When the moon is in its waxing phase, it

looks similar to the capital letter ‘D’, in that the right side of the moon is smooth and rounded; whereas, the left side looks more uneven and darkening.

– When the moon is in its waning phase, it appears more like the capital letter ‘C’; the right side appears darker, more indistinct, while the left side is smooth and rounded.

• How are the alike?– Mirror images of each other

• What is a moons phase when it is close to the sun? – a thin Crescent, or new moon

Tides• Ever notice that in the ocean, sometimes the

water is higher, and sometimes it is very low?• This change in water lever is referred to as Tides• The moon is responsible for tides. How?– Most places in the ocean usually experience two high

tides and two low tides each day (but some locations experience only one high and one low tide each day. The times and amplitude of the tides at the coast are influenced by the alignment of the Sun and Moon. The gravitational forces of the moon control tides. Because the moon pulls on the earth with its gravity, and because water is fluid, the water actually moves.

Activity

• In this activity, the students will use a model to explain the moon’s monthly cycle of phases. The students’ head will represent the earth. They hold “moon balls” in their outstretched hands and slowly move them in circles around their heads. With a single lamp, “the sun” lighting up the students “moon” the students are able to observe moon phases and eclipses.

Set up

• Use the extension cord and set up the lamp. Place the lamp in an easily accessible area.

• Hand out one Styrofoam ball to each student. They can stick the balls on pencils for easy holding if they want.

• Explain that their head is the earth in this model and the lamp is the sun. they are in charge of moving their balls or “moon” to observe different moon phases.

Moon Activity• Ask the students to hold their

moon balls out in front of them, directly in front of the “sun”.

• Tell them to move the ball a little to the left until they can see a little crescent light up.– Observe that the bright side of

their “moon” is facing the sun• Tell them to keep moving the

balls around their heads in the same direction until exactly half of the moon is lit.– Ask, to make a moon

appear fuller, does it have to move toward the sun or away from it? (away from the sun, just like the real moon)

Moon Activity• Tell the students to continue moving the

moon in a circle until the part they see is fully lit. explain that to do this, they will have to hold the moon ball just above the shadow of their heads. – Ask, when the moon is full, is it between

you and the sun, or on the opposite side of you from the sun? (it is on the opposite side of you from the sun)

• Instruct the students to continue moving the moon in the same direction until it is just half full again.– Ask, as the moon moves towards the sun,

does it appear to get fuller or thinner?• Tell them to continue moving their moons

until they are very thin crescents. – When the moon is very close to the sun

we cannot see it in the day or night because the sun is so bright.

Eclipses

• Once they have grasped these concepts shown in the model, have the students hold their moons directly in front of the sun to create a solar eclipse.

• Tell them to look around and observe the shadows on everyone’s eyes. Remind them that since their head represents the earth, the people who live where their eyes are can see the solar eclipse. But the people who live where their ears, nose, and chin are unable to see the eclipse. They see the sun.