Tides and Eclipses

Tides

• The tides are the rising and falling of the ocean surface as a result of the gravitational pull of the moon and the Sun on the earth.

• The Moon plays a bigger role than the Sun because it is closer.

Effect of the Moon on the Tides

Water gets pulled towards the moon: High Tide in this location.

Water bulges on opposite side from the moon also: High Tide in this location

Low tide here, and on opposite side on the earth that you can’t see.

Role of the Sun

• The sun also has a gravitational pull on the earth. – When the sun is lined up with the moon and

the earth, it “helps” the moon pull on the earth,

and the tides become more extreme.– When the sun is not lined up with the moon and

the earth, it partially cancels out the pull of the moon, and the tides are less extreme.

Spring Tides

• Sun, earth and moon are lined up.

• Higher high tide, Lower low tide.

Regular Tide Level

Tide Level during Spring Tides

Neap Tides

• High tide is lower than normal, and low tide is higher than normal. There is less difference between the level of the tides.

Regular High tide level

High Tide level during neap tides

Occurrence of Neap and Spring Tides

• Spring tides occur when sun, moon and earth are lined up: Full Moon and New Moon.

Neap Tides occur when the sun and moon pull in opposite directions: First Quarter and Last Quarter.

Eclipses

• There are two types of eclipses:– Solar Eclipse- When the moon lines up

exactly in between the sun and the earth. It blocks out the sun so we can’t see it.

– Lunar Eclipse- When the earth lines up exactly in between the moon and the sun, and prevents sunlight from reaching the moon. Or, another way to say it is the moon moves into the shadow of the earth.

Solar Eclipse

• Occurs when the moon is a New Moon and lined up perfectly with the sun and earth.

Places on earth in the Penumbra will see a Partial Solar Eclipse

Places on earth in the Umbra see a Total Solar Eclipse

Solar Eclipse

Lunar Eclipse

• Occurs when the moon is a Full Moon and the earth, moon and sun are exactly lined up.

Lunar Eclipse