Tides

Tides

6SC.A.3.e: analyze and interpret data to create graphic representations of the causes and effects of waves, currents, and tides in Earth's systems

The daily rise and fall of Earth's waters on shores.

What causes tides?

Tides are caused by the interaction of Earth, the moon, and the sun.

What type of force causes tides?

• Gravity

Tides

• Tides are great bulges of water caused by the gravity of the Moon and Sun. 

• Attracted by gravity, these bulges move around the Earth’s oceans, causing water levels to rise and fall. 

About how often do high tides occur in most places?

The high tides occur about 12 hours and 25 minutes apart

Multiple Choice

A student is visiting Hilo, Hawaii, and he wants to collect seashells. The local people tell him that the best time to collect shells is at low tide. The tides in Hilo, Hawaii, during his visit are shown above. According to the diagram, at what time should he collect shells? (DOK 3)

• 9:00 AM

• 12:00 PM

• 3:00 PM

• 7:00 PM

Spring Tide

A tide with the greatest difference between high and low tide that occurs when the sun and the moon are lined up with Earth. 

Neap Tide

A tide with the least difference between low and high tide that occurs when the sun and moon pull at right angles to each other.

Multiple Choice

Which term best describes the rise and fall of the ocean's water level?

• Sudden

• Neverending

• Random

• Unpredictable

Multiple Choice

Which of the following is a true statement about gravity?

• It acts on all matter in the universe.

• It pushes objects away from one another.

• It does not exist in outer space.

• It gets weaker the closer you get to the sun.

Multiple Choice

If the sun is bigger than the moon, why does the

moon have a greater effect on tides?

• The sun's gravity doesn't affect water.

• The moon is much closer than the sun.

• Although the moon is smaller than the sun, it has

  more mass.

• The earth blocks the sun's gravitational pull.

Multiple Choice

High tides occur:

• At either the North Pole or South Pole, depending on

  where the moon is.

• On the side of the earth facing away from the moon

  only.

• On the side of the earth facing the moon only.

• On the side of the earth facing the moon, and also the opposite side.

Multiple Choice

Based on information from the movie, what would

you expect to happen to the number of high tides in

any given area if the rate of earth's rotation doubles?

• They will occur about as often as before

• They will occur about half as often

• They will occur about four times more often

• They will occur about twice as often

Multiple Choice

At one beach, high tide occurs at 8 a.m. When will

the next high tide most likely occur?

• Noon

• 4 p.m.

• 8 p.m.

• 8 a.m. the next day

Multiple Choice

Which of the following is a true statement about

tidal energy?

• It's easy to harness

• It's more efficient than solar energy

• It's more powerful than the energy we get from fossil

  fuels

• It causes very little pollution

Multiple Choice

What might happen on a beach as the tide goes

out?

• Sand castles built by kids might get washed away by

  the ocean.

• The waves will almost definitely grow taller and more powerful.

• There will be more sand for beachgoers to sunbathe

  on.

• Sand dunes and other formations will begin eroding.

Multiple Choice

What might happen if the moon were only half as

large as it is now?

• There would be no tides

• Most areas would receive fewer high tides each day

• The ocean level would rise and fall less dramatically

• Ocean waves would not be very large

Multiple Choice

The moon's gravity affects:

• Both the solid parts of the earth and the oceans

• The solid parts of the earth only

• The oceans only

• The moon only