Earth's Cycles

Helpful study links:

This link is flash card practice. And more flash card practice.

And this is flash card practice of just the moon phases and names.

Seasons

There are two reasons why we have seasons:

#1 - The Earth is tilted at 23.5 degrees. This cause one hemisphere to lean in to the sun getting more direct heat (summer) and the other hemisphere to lean away from the sun getting less direct heat (winter).

#2 - The revolution of the Earth around the sun.

Note: the Earth's distance from the Sun has NOTHING to do with season! In fact, the Earth is closest to the sun during our winter!

Moon Phases

In 8th grade, you know only need to be able to identify the shape of the moon with the name, but also understand WHY the moon has that shape. Make sure you understand the Earth, Moon and Sun in relation to each other. You also need to be able to predict moon phases.

Gif-tionary of moon phases and eclipses

Lunar and Solar Eclipses

Lunar (moon) eclipse is when the moon is being covered by Earth's shadow. For this to happen, the Earth has to be between the Sun and the Moon. This can only occur during a full moon phase. Lunar eclipses are perfectly safe to watch with the naked eye. Looking at a lunar eclipse is no different than looking at a full moon.

Solar (sun) eclipse is when the sun is being covered by the moon. For this to happen, the Moon has to be between the Earth and the Sun. This can only occur during a new moon phase. Watching a solar eclipse can cause damage to your retina. You should only watch a solar eclipse with proper solar eclipse eye protection.

Tides

Tides are just the rising and lowering of the sea level. This is caused by the gravitational pull of the moon on the water. Since the moon orbits our earth in a pattern, tides occur in a daily and well as monthly pattern.

Every day there are two high tides and two low tides. As the earth goes through it's 24 hour rotation, the tides will rise and lower with 6 hours in between each.

During new moon and full moon phases, the earth, moon and sun are aligned in a straight line. Not only is the moon's gravitational pull pulling on the water but so is the sun's gravitational pull. Since there is extra pull on the water, the high tides are extra high during new moon and full moon. This causes low tide sea levels to be extra low. During new moon and full moon phases, this special type of tide is called a spring tide. An easy way to remember this is Spring tide = Straight line.

During first quarter and last (third) quarter moon phases the opposite occurs. Instead of the earth, moon and sun being aligned, they are at a ninety degree angel to each other. Instead of the moon and sun working together to pull on the water, their pulls sort of cancel each other out. During first quarter and last quarter moon phases, there are still two high and two low tides each day. It's just that the high tides are not as high and the low tides are not as low. This type of tide is called a neap tide and it only occurs during first quarter and last quarter moon phases. An easy water to remember this is Neap tide = Ninety degree angle.

In case you were wondering....

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