Transcript Tides & Eclipses - Rutherford County Schools

• What are tides?
TIDES
– The periodic rise and fall
of the sea level under the
gravitational pull of the
moon
• Tides are one of the
most reliable
phenomena in the
world. As the sun rises
in the east and the stars
come out at night, we
are confident that the
ocean waters will
regularly rise and fall
along our shores.
• The Moon’s gravity
exerts a strong pull on
Earth.
• The water bulges
outward as Earth and
the Moon revolve
around a common
center of mass.
• The moon’s gravity pulls
on the earth, and pulls
the water towards it. The
water moves up into a
slight bulge on the side
of the earth that faces
the moon.
Tide
Spring Tides
• Spring tides occur 2 times a month,
during a full and new moon when
the Earth, Sun, and Moon are lined
up.
• Spring tides are higher and lower
than normal tides.
• “strong tides”
Spring Tides
• Spring tides are especially
strong tides (they do not have
anything to do with the season
Spring). They occur when the
Earth, the Sun, and the Moon
The
gravitational forces
of the Moon and
the Sun both
contribute to the
tides making them
stronger.
are in a line.
Neap Tides
• Neap tides occur in between spring
tides, at the first and third quarters
of the Moon when the Sun and
Moon pull at right angles to each
other.
• Neap tides are not
as high or low as
normal tides.
• “weak tides”
Neap Tides
• When the moon and
sun are at a
perpendicular angle
to one another the
Moon & the Sun’s
gravity cancel each
other out causing a
weaker tide.
• They occur when the
gravitational forces of the
Moon and the Sun are
perpendicular to one
another (with respect to
the Earth). Neap tides
occur during first and third
quarter moons.
Chapter 14
Standardized Test Preparation
1. At which position would the
moon be during a neap tide?
A1
B2
C3
D4
Chapter 14
Standardized Test Preparation
2. At which position would the
moon be during a spring tide?
F1
G2
H3
I 4