If you watch the Moon from night to night you will notice that it seems “wax” larger from a new moon to a full moon then “wane” smaller from a full moon back to new. The time from one new moon to the next is about 29.5 days and is called a lunar month. • In fact the time it takes for the moon to go from any phase to the next time it shows the exact same phase is a lunar month.
The Source of Moon phases • The Moon’s orbit around the Earth causes the Moon to have phases. The phases are NOT caused by the Earth’s shadow!
Your group will model the Moon as it orbits around the Earth. Your head will become the Earth and you will hold a small ball as the Moon. A light source will be the Sun. You will also be completing a scriptsheet.
What Phase? • Waxing Crescent
What Phase? • First Quarter
What Phase? • Waxing Gibbous
What Phase? • Full Moon
What Phase? • Waning Gibbous
What Phase? • Waning Crescent
Moon Phases • A few rules will help you understand Moon phases.
Crescent Moon • The Moon will be a crescent when it is closer to the Sun than you are.
Gibbous Moon • The Moon will be gibbous when it is farther from the Sun than you are.
Waxing Moon • The Moon will be waxing as it travels away from the Sun.
Waning Moon • The Moon will be waning as it travels toward the Sun.
These rules can be used to understand phases seen with other objects in other places.
The Moon is at First Quarter because it is at the same distance from the Sun as the Earth. Since the Styrofoam ball is also on the Earth it shows the same phase.
Both the Moon and the water tower are closer to the Sun than the photographer so both are crescents. Is the Sun to the left or right of the picture?
The water tower on the left is even closer to the sun so it is an even thinner crescent.
Other Phases • Earth Phases can be seen from the Moon. Question Which is closer to the Sun, the Earth or the Moon?
Earthrise Question Which is closer to the Sun, the Earth or the Moon?
Eclipses • Eclipses occur when the shadow of one object in space covers another
Lunar Eclipses • Lunar Eclipses occur when the shadow of the Earth covers the Moon. They can only occur during the Full Moon.
The Earth is Round! • The shape of the Earth’s shadow has long been used to see both the size and true shape of the Earth.
Lunar Eclipses Lunar eclipses can be seen from half the Earth. More people get the chance to see Lunar eclipses than Solar Eclipses.
Solar Eclipses • Solar Eclipses occur when the shadow of the Moon covers part of the earth. They can only occur on the New Moon.
Partial Eclipse Partial eclipses are seen when the Moon covers only part of the Sun from the viewers location.
Total Eclipse Total eclipses are seen when the Moon covers all of the Sun from the viewers location.
Transit An eclipse is similar to a transit. A transit occurs when one astronomical object passes in front of another. Here Venus is passing in front of the Sun.
Tides Tides are caused by gravity. It is not only the strength of gravity that causes tides but how gravity grows weaker with distance.
The gravitational pull of the Sun or a planet is greater on nearby objects.
The gravitational pull of the Moon pulls ocean water to the side of the earth facing the Moon. Water is also “left behind” on the opposite side of the Earth.
Both the Sun and the Moon create tides. The Moon’s tides are greater than those of the Sun. These two tidal cause can work together or opposite to each other.