Science: 4-3.6 Illustrate the phases of the Moon and the Moon’s effect on ocean tides.
The Moon reflects light from the Sun. The positions of the sun, moon, and Earth make the moon appear to change shape.
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Essential Question: Why does the shape of the moon seem to change and how do I identify each shape?
Moon Phases
The moon is the brightest object in the night sky. But the moon does not give off its own light. The moon’s surface reflects, or bounces back, light from the sun. The sun always lights one-half of the moon.
The moon itself is always a round ball. That shape does not change. What does change is how much of the sunlit half of the moon we can see. Phases are the different shapes of the moon that we see from Earth. The diagram above shows nine phases of the moon. There are four main phases of the moon: New Moon, Quarter Moon, Full Moon, and Crescent Moon.
The phase called a new moon appears when the bright side of the moon faces away from Earth. All we see is the dark side. Most often, a new moon looks like a no moon at all. A full moon looks like a bright, round circle. During a full moon, we see the whole bright side.
During a quarter moon, we see half of the sunlit side of the moon. In other words, we see one-quarter of the moon. The moon looks like half of a circle. For that reason, a quarter moon is sometimes called a half moon. There are two quarter moon phases in the cycle.
The moon also has crescent and gibbous phases. During a crescent moon, we see less than half of the moon’s bright side. During a gibbous phase, we see more than half of the bright side.
The change in the Moon’s phases from new moon to new moon takes about four weeks, or 29 ½ days.
Why We See Phases
Look at this diagram. The outside circle shows the moon revolving around Earth. You can see that the sun always lights half of the moon. Inside of the circle shows the phases that we see from Earth. The phases change as the moon moves in its orbit.
Moon Phases
The moon is the brightest object in the night sky. But the moon does not give off its own light. The moon’s surface reflects, or bounces back, light from the sun. The sun always lights one-half of the moon.
The moon itself is always a round ball. That shape does not change. What does change is how much of the sunlit half of the moon we can see. Phases are the different shapes of the moon that we see from Earth. The diagram above shows nine phases of the moon. There are four main phases of the moon: New Moon, Quarter Moon, Full Moon, and Crescent Moon.
The phase called a new moon appears when the bright side of the moon faces away from Earth. All we see is the dark side. Most often, a new moon looks like a no moon at all. A full moon looks like a bright, round circle. During a full moon, we see the whole bright side.
During a quarter moon, we see half of the sunlit side of the moon. In other words, we see one-quarter of the moon. The moon looks like half of a circle. For that reason, a quarter moon is sometimes called a half moon. There are two quarter moon phases in the cycle.
The moon also has crescent and gibbous phases. During a crescent moon, we see less than half of the moon’s bright side. During a gibbous phase, we see more than half of the bright side.
The change in the Moon’s phases from new moon to new moon takes about four weeks, or 29 ½ days.
Why We See Phases
Look at this diagram. The outside circle shows the moon revolving around Earth. You can see that the sun always lights half of the moon. Inside of the circle shows the phases that we see from Earth. The phases change as the moon moves in its orbit.
Waning:
When the moon is called “waning,” that means that the moon is getting “smaller,” as in the amount of the moon we see is getting lesser. |
Waxing:
When the moon is called “waxing,” that means that the moon is getting “larger” in a sense. As in, more of the moon is going to start showing, and the amount of the moon we see is getting larger. The waxing starts from right to left. |
The Moon and Tides Essential Question:
What is the moon’s effect on ocean tides? The Cause of Tides The rise or fall of water along a shore is called a tide. Gravity causes tides. Gravity is the pull that exists between all objects. Earth pulls on the moon and keeps it moving around the planet. The moon also pulls on Earth, including Earth’s oceans. The moon’s gravity causes ocean water to bulge out on the side of Earth that faces the moon. At the same time, the moon also pulls on the solid part of Earth. Earth is pulled slightly toward the moon. This leaves a bulge of water on the opposite side of Earth. These two bulges are known as high tides. During high tide, water reaches its highest level along a shore. The places on Earth that are halfway between the high tide points have low tides. During low tide, water reaches its lowest level along a shore. The Pattern of Tides You know that Earth rotates, or spins on its axis. So the moon pulls more on different part of Earth at different times of day. Most shores have two high tides and two low tides each day. In most places, about 12½ hours pass between high tide and the next. |
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Learning Tasks & Assessments:
Notebook Entry: Use the Moon Phase Diagram (Reading A-Z) and draw the phases of the moon. (DOK 1) Formative Assessment: Write Like a Scientist: Why Does the Moon Change Shape? With a partner, develop and use a model to show how an object can look different based on its position as it reflects light. Respond in writing to the following questions (See Write Like a Scientist): How does your model demonstrate how an object appears to change shape? How does your model help you understand the phases of the moon? (DOK 3) Assessment Guidelines: The objective of this indicator is to illustrate phases of the Moon and the Moon’s effect on tides; therefore, the primary focus of assessment should be to give or use illustrations to show aspects of these concepts. However, appropriate assessments should also require students to recall information about the Moon’s reflecting light, the time it takes for a complete phase cycle to complete, or the cause of tides; or classify by sequencing the order of the Moon phases. |
Resources:
DE Text: Phases of the Moon 1 Phases of the Moon 2 Reading A-Z : Moon Phase Diagram: Discovery Education Video: The Sun, Moon and Tides Brain Pop: Tides Moon Phases - Movement: Study Jams Video on Tides Discovery Education TechBook: Phases of the Moon Constructed Response Write Like a Scientist: Why Does the Moon Change Shape? |