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Gravity and Tides. Today’s Objectives . Draw conclusions about the cause and occurrence of tides Analyze patterns in the times and heights of tides, moonrise and moonset times, and phases of the Moon along Virginia Beach. Opening Discussion. What are tides? What causes tides?.
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Today’s Objectives • Draw conclusions about the cause and occurrence of tides • Analyze patterns in the times and heights of tides, moonrise and moonset times, and phases of the Moon along Virginia Beach.
Opening Discussion • What are tides? • What causes tides? Fundy Bay Video Clip • http://www.youtube.com/watch?v=5W2sM1Ma7YA
Demonstration #1: • Water Balloon • Why does the shape of the balloon change shape?
Demonstration #2 • Why does the water stay in the bucket?
What causes tides on Earth? • Cause 1: Moon’s gravitational pull of the water creates the bulge on the side of the Earth closest to the Moon MOON EARTH
What causes tides on Earth? Cause #2: The outward force that occurs as a result of the moon’s orbit (revolution) EARTH MOON
Why Do We Have Tides? Gravity Centripetal Force
What causes tides on Earth? • Cause #3: The Rotation of the Earth within the bulge. Britannica Link
Why Do We Have Tides? Gravity Outward Force Rotation of Earth
What causes tides on Earth? Summary: What are the 3 causes of tides on Earth 3 Reasons we experience tides on Earth? • Gravitational pull of moon on Earth’s oceans • The outward force that occurs as a result of the moon’s orbit (revolution) • The Rotation of the Earth within the bulge.
Applying What You Know • You are now going to analyze patterns in the times and heights of tides, moonrise and moonset times, and phases of the Moon along Virginia Beach.
Questions for Analyzing Tide Data • About how much time passes between one high tide and the next high tide? • About how much time passes between one low tide and the next low tide? • How many high tides and low tides occur during one rotation of the Earth (1 day)? • Number of high tides: • Number of low tides • Why aren’t high tides the same time every day? • If the second high tide on April 30th is at 2:15 p.m., then predict what time the second high tide will occur on May 1st? Why? • During what phases of the moon do the largest tidal range (variation between high and low tide) happen?