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Chapter 6 Lesson 5 Tides. Objective : Explain what causes tides. What are Tides?. High Tide = water @ Highest point Low Tide = Water @ Lowest point Last about 6 hours Causes by gravity of: The MOON The SUN.
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Chapter 6 Lesson 5 Tides Objective: Explain what causes tides.
What are Tides? • High Tide = water @ Highest point • Low Tide = Water @ Lowest point • Last about 6 hours • Causes by gravity of: • The MOON • The SUN http://studyjams.scholastic.com/studyjams/jams/science/weather-and-climate/tides.htm
Tide Cycle Tides are caused mainly by differences in how much gravity from the moon and the sun pulls on different parts of Earth.
What are Tides? Spring Tide Neap Tide • Sun, Earth, & Moon are in a straight line • Doesn’t matter what order • Happens about twice a month • Full moon & New moon • BIGdifference between high and low tides • Sun, Earth, & Moon are at a 90 degree angle • Happens about twice a month • First quarter & Third Quarter • smalldifference between high and low tides
The Sun’s Role Changes in the positions of Earth, the moon, and the sun affect the heights of the tides during a month. What is the position of the moon and where are the tide bulges at third quarter? http://www.youtube.com/watch?v=RZOsafzcWZA
Review Questions • Why do most coastal regions have two high tides and two low tides each day? • High tides occur on both the side of Earth closest to the moon and the side farthest from the moon. Every point on Earth moves through these two locations each day. Low tides occur between each tide. • How does the size of high and low tides in a spring tide compare with the size of high and low tides in a neap tide? • During a spring tide, high tides are higher than usual, and low tides are lower than usual. During a neap tide, the situation is reversed.
High and Low Tides The table shows high and low tides at four times in May 2008, in St. John, New Brunswick.