7 th Grade Science Unit: Earth, Sun, and Moon Lesson: ESM 9_ Tides 1 Name: Date: Thursday, October 27, 2016 Homeroom: OBJECTIVES: By the end of today s lesson, you will be able to SWBAT explain how the gravity of the moon causes tides in Earth s oceans. DO NOW Directions: Using the pictures to help, define the following terms. Term/Picture Solar Eclipse Definition Lunar Eclipse Umbra 1
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Practice Beyond Perfection!! Draw all 8 planets in our solar system, given the position of the sun below. Be sure to make each planet look different, and put them in the correct order! 3
I DO CLASS NOTES Specialized Terminology Tides- Tides are the and of sea levels caused by the gravitational forces exerted by the Moon and the Sun. Examples: High tide (the level of the ocean at its highest point) Low tide (the level of the ocean at its lowest point). 4
Gravity- the force of between all masses in the universe. The the mass of an object, the more gravitational pull it will have. This is why all of the planets orbit the. Why do you think a moon can t have a larger mass than its planets? Gravity is a major responsible for creating tides (the rise and fall of levels). a. In1687, Sir Isaac Newton explained that ocean tides happen because of the gravitational attraction of the and the on the oceans of earth. i. Newton s law of universal gravitation states that the gravitational attraction between two bodies is directly proportional to their masses. 1. So the something is the gravitational pull it will have. ii. Newton s law also says that the farther away two objects are, the the gravitational pull there will be between them. 1. Therefore, the greater the mass of the objects and the closer they are to each other, the greater the gravitational pull between them. 2. So, the smaller the mass of the object and the farther away they are from each other, the the gravitational pull between them. 5
Tides are caused by the gravitational pull of the Moon. a. The gravitational pull of the Sun also affects tides. Even though the Sun is 27 million times the size of the Moon, it has less of an effect on the tides because the Sun is so much away from the Earth than the Moon is. Tides change in Earth s oceans approximately every hours. When the ocean has risen to its highest point, it is called. b. When the ocean is at its lowest point, it is called. i. The closer a place is to the equator, the the range will be. ii. The farther away a place is to the equator, the the range will be. The difference between low tide and high tide is called the 6
For example, the largest tide change occurs in the Bay of Fundy which is in Eastern Canada. 7
Types of Tides 1. There are two types of tides on Earth s surface. Name Picture Description Neap Tides are created when the Sun, Earth, and Moon create a right triangle. The pull of the Sun counteracts the pull of the moon. This type of tide happens twice a month. During neap tides, the difference between high and low tides is very small. There is a small range. Spring tides occur when the Earth, Sun, and Moon create a straight line. At these times, the high tide is very high and low tides are very low. Spring tides are very strong. 8
GUIDED PRACTICE 9
INDEPENDENT PRACTICE Directions: For each of the pictures below, decide which term it is describing. Then, write a definition for that term. Term Picture Definition 10
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7 th Grade Science Unit: Earth, Sun, and Moon Lesson: ESM 9_ Tides 1 Name: Date: October 27, 2016 Homeroom: /5 = % DNG? Strive Due Date: A B C D F Directions: Match the following terms with the correct definition 1. Neap Tide 2. Tides 3. High Tide 4. Gravity 5. Spring Tide 6. Low Tide 7. Tidal Range A. The rise and fall of sea levels caused by the combined effects of the rotation of the Earth and the gravitational forces exerted by the Moon and the Sun. B. When water in the ocean is at its highest point. C. The type of tide that occurs when the Sun, Earth, and moon form a right angle. These tides are not very strong. D. the force of attraction between all masses in the universe. The larger the mass of an object, the more gravitational pull it will have. This is why all of the planets orbit the Sun. E. The difference between the highest level and lowest level of the ocean. F. When water in the ocean is at its lowest point. G. The strongest type of tides which occurs when the Sun, Earth, and Moon are in a straight line. 13 TURN OVER
Directions: For the following terms, draw a picture to describe it. Then, write a definition to explain the term in words Term Definition Picture Neap Tide Spring Tide Tidal Range 14