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2	The Movement of Earth Gravity: Gravity is a force of attraction between any two objects. Gravity governs the movements of the planets, moons, asteroids and comets in our solar system. Earth’s Movements: Earth rotates on its axis, causing day and night. 1. Earth revolves around the Sun. 2. The tilt of the Earth’s axis explains the change of seasons as Earth revolves around the Sun.
3	Stars and Phases of the Moon Stars: Scientists believe stars were formed out of clouds of gases and dust in space known as nebula. Stars produce energy through nuclear fusion, converting hydrogen into helium. Stars create all elements besides the lighter gases. Lunar Phases: The appearance of the Sun’s reflected rays on the moon and the moon's position in its orbit around Earth are responsible for the various phases of the moon.
4	Space Review Moon Phases Types of Galaxies
5	What Causes Seasons? The seasons are caused by a combination of things: The Earth is tilted as it moves around the sun. Direct sunlight produces more heat than indirect light. The Earth revolves around the sun. The difference in the amount of sunlight reaching the ground in the different hemispheres is what causes the seasons.
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7	Equinoxes
8	Seasons
9	Seasons
10	Earth’s Land Features Tectonic Plates: These are pieces of the Earth’s crust and the rock below, about 100 Km thick, that slowly move on the Earth’s surface. Their movements can create mountains, seafloor spreading, earthquakes and volcanoes. Plate Tectonic Review Weathering: wearing down of rock by wind, water, ice and living organisms. Erosion: When rock or soil is broken down into pebbles, sand of dust and transported away. Land Subsidence: When part of the Earth’s surface weakens and sinks
11	Continental Drift
12	Layers of the Earth (click picture to review)
13	Layers of the Atmosphere click on picture to review
14	Earth’s Cycles Cycles can be analyzed and predicted. Rock Cycle: Rocks move from igneous to sedimentary to metamorphic and back again. Water Cycle: Water evaporates from the ocean and other surfaces. Water then condenses into clouds and later falls back to the ground as precipitation. Ground and surface water collect in a watershed and drain off into the ocean. Carbon and Nitrogen Cycles: Involve living things: for example, plants create organic compounds; animals eat plants; carbon is released from their remains, wastes and respiration.
15	Carbon Cycle click the picture to review more
16	Nitrogen Cycle (click picture to review)
17	Rock Cycle (click picture to review)
18	Water Cycle (click picture to review)
19	The Interaction of Earth’s Systems Earth’s Systems: Earth’s systems often interact. For example, solar energy and water from the oceans interact with the atmosphere to create weather patterns. Influence of Disastrous Events: Catastrophic events, like a meteor crash, can lead to the extinction of an entire species. An endangered species is protected by government agencies because it is close to extinction.
20	Impact of Humans on Earth’s Systems Environmental problems: Global Warming: Burning of fossil fuels has increased carbon dioxide in the air. Ozone Layer: Absorbs much of the Sun’s ultraviolet radiation, but is being destroyed by CFSs. Pesticides: Pesticides can poison water, soil and the food we eat. Acid Rain: Air pollutants turn into acids that are highly toxic Loss of Non-Renewable Resources Destruction of Natural Habitats
21	Environmental Problems (click pictures to review)
22	Weathering and Erosion Weathering is the breakdown and alteration of rocks and minerals at or near the Earth's surface.
23	Weathering and Erosion Erosion is the wearing away of land or soil by the action of wind, water, or ice.
24	Types of Weathering Physical or mechanical weathering Ice wedging - water expands when it freezes and breaks apart rocks
25	Types of Weathering Physical or mechanical weathering Exfoliation - caused by expansion of rock due to uplift and erosion; rock breaks off into sheets along joints which parallel the ground surface (called sheeting).
26	Types of Weathering Physical or mechanical weathering Thermal expansion - repeated daily heating and cooling of rock; heat causes expansion; cooling causes contraction.
27	Types of Weathering Chemical weathering - Rock reacts with water, gases and solutions (may be acidic); will add or remove elements from minerals.
28	Types of Weathering Biological weathering - Organisms can assist in breaking down rock into sediment or soil.
29	Weathering
30	Types of Erosion Water Erosion – Water is the most important erosional agent and erodes most commonly as running water in streams. However, water in all its forms is erosional. Raindrops (especially in dry environments) create splash erosion that moves tiny particles of soil. Water collecting on the surface of the soil collects as it moves towards tiny rivulets and streams and creates sheet erosion
31	Types of Erosion Glaciers (frozen water) can cause erosion - they pluck and abrade. Plucking takes place by water entering cracks under the glacier, freezing, and breaking off pieces of rock that are then transported by the glacier. Abrasion cuts into the rock under the glacier, scooping rock up like a bulldozer and smoothing and polishing the rock surface
32	Types of Erosion Wind Erosion – Erosion by wind is known as aeolian erosion (named after Aeolus, the Greek god of winds) and usually occurs in deserts. Aeolian erosion of sand in the desert is partially responsible for the formation of sand dunes. The power of the wind erodes rock and sand.
33	Types of Erosion Wave Erosion – Waves in oceans cause coastal erosion. The energy of the waves along with the chemical content of the water is what erodes the rock and sand of the coastline.
34	Erosion
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