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How to Make a 3 Dimensional Model of the Moon's Phases

Making a three-dimensional model of the moon̵7;s phases can help you understand why the moon has phases and give you an idea for a science fair project. The moon appears different at different times of the month, ranging from entirely black, to crescent-shaped and even fully illuminated. This happens because of the relationship between the sun, the moon and the Earth. The light of the sun only shines on half of the moon at any one time, but the moon isn̵7;t always at the same position in relation to the Earth. Make a 3D model to illustrate the reasons for this.

Things You'll Need

Polystyrene foam balls
Large, flat polystyrene foam surface
Pencils/toothpicks
Lamp
Protractor
Ruler

Instructions

- 1
  Lay out your flat piece of polystyrene foam on a flat surface. Mark the central point of this piece of polystyrene with a small hole. Make this using a pencil or toothpick. Put a polystyrene foam ball in the center of the flat piece. It should sit on top of the hole you created. Paint the ball blue and green to represent water and land if you wish. This ball is your model̵7;s Earth.
- 2
  Choose a starting point on your flat piece of polystyrene. This is simply a location for the ̶0;new moon̶1; phase. Later, the light source will also be placed in this general direction. If you have a square piece of polystyrene foam, use the middle of the right edge for your starting point. Use a ruler to draw a straight line from the Earth directly to the center of the right edge. Push a toothpick or pencil into the polystyrene foam to mark this point.
- 3
  Remove your Earth and place a protractor on the spot you made to mark the center of the polystyrene. Point the ̶0;0̶1; degrees marker at your first toothpick. Using a ruler, place a toothpick into the polystyrene at the same distance from the center as the first one at the 45-, 90-, 135- and 180-degree points. Turn the protractor around so that the ̶0;0̶1; degree marker points in the opposite direction. Push toothpicks into the polystyrene foam at the same points on this side. You will already have toothpicks at zero and 180, so just fill in the ones at 45, 90 and 135 degrees, remembering to keep the same distance from the center.
- 4
  Place polystyrene balls on top of each toothpick. Put your ̶0;Earth̶1; ball back on the center point. You now have eight spheres surrounding a central ball. These spheres represent the different locations of the moon during its orbit.
- 5
  Remove the shade from a lamp and plug it in. Put the lamp off in the direction of your starting, or ̶0;0̶1; degrees, point. The lamp should be at least 3 feet away from the polystyrene foam. Turn on the lamp and turn out the lights in the room. Close any curtains or cover the windows to get the best effect. The lamp represents the sun, and the various balls represent the waning and waxing phases of the moon. The full moon is exactly opposite the light source, and the new moon is on the same side as the light source. Look from Earth̵7;s perspective to see why different moon phases occur.

Astronomy