Lesson 16 – Things you need to know but they are not on the reference table.

Light Light is a form of energy that moves in waves. There are many different types of light because there is so many different wavelengths of light. We see a small portion of light know as visible light. Visible light contains all the colors that we see. Moving objects can change the color of light that is being reflected on it if the object is compressing or stretching the light’s wavelength. This compressing and stretching of wavelength is known as the Red Shift. Objects that are moving toward you compresses the lights wavelength making it appear slightly blue. Objects that are moving away from you stretches the lights wavelengths, making it appear slightly red. Important – The object does not turn red or blue, but to the observer, the color appears to change color.

Heat Heat is the release of energy that can cause a change in temperature. Heat has the ability to move in three ways: Conduction – Conduction transfer requires that an object touches a heat source. The heat travel through the object until it reaches the other side. Radiant – Radiant transfer uses waves of energy (light) to travel through air and space until it reaches a liquid or solid surface. The air and space does not heat up, but the liquid and solid starts heat up. Objects that are dark and/or rough absorb radiant heat. Objects that are light and/or smooth reflect radiant heat Convection currents - Convection currents form as the results of the movement of materials of different temperatures that create different densities. As a liquid or gas is heated up by a heat source their density lowers. The lower density causes the substance to rise. But as it rises, it moves away from the heat source and behinds to cool down. As it cools, it density increases causing it to sink. Now that it sinks, it gets close to the heat source and the everything repeats.

Where did the Earth gets its Atmosphere When the Earth first formed, it had no atmosphere. Scientist speculate that early earth was very volcanically active, partly due to the many bombardments of comets and meteors hitting the planet. Gases trapped inside the Earth were able to escape onto the surface. And as the temperature decreased and Earth’s gravity stabilized, the escaped gases formed the atmosphere. During this time, life could not exist. It wasn’t until the Earth cooled down enough and the arrival of water from impacting comets that plants developed and grew. For millions of year, only plants existed, but as they lived, they converted the carbon dioxide in the atmosphere into oxygen. When enough oxygen was accumulated, animals started to appear.

The Green House Affect With the start of the industrial revolution, in the mid 1800’s, man has been increasingly adding carbon dioxide and methane into the atmosphere. Carbon dioxide and methane are greenhouse gases .Greenhouse gases trap the heat radiating from the Earth causing the global temperature to rise. As a results of the greenhouse affect, many weather patterns are changing. Melting Ice Caps Stronger tropical storms Hurricanes and monsoons Changing ocean currents patterns El Niño and la Nina

Weather The lower layer of the atmosphere is where weather occurs. In the United States, weather tends to move from west to east. There are three major components of weather: Wind – the movement of air from one place to another. Wind speed in measured using an anemometer, and wind direction by a wind vane Air moves from areas of high pressure to areas of low pressure In high pressure areas, wind move in a clockwise direction and away from the high pressure center. In low pressure areas, wind move in a counter clockwise direction and towards the low pressure center. Air pressure refers to the amount of air over a particular location. Air pressure is measured by a barometer. Warm air tends to have low pressure and cold air tends to have high pressure. At the beach during the day, the wind moves from the ocean (cool water) to land (warm land) At the beach during the night, the wind moves from the land (cool land) to ocean (warm water) Temperature – the amount of heat in the air. Temperature is measured by a thermometer Warm air tends to come from tropical areas (low latitudes). Warm air can form over warm ocean currents. Cold air tends to come from polar areas (high latitude and high altitudes). Cold air can form over cool ocean currents. Moisture - the amount of water in the air Humidity is the term used to describe the amount of moist in the air. Zero humidity means that the air is dry; 100% humidity means that the air is saturated with moisture (rain). Air gets is moisture from bodies of water as they move across them. Air losses it moisture as it moves over dry land it the form of rain and snow. Warm air can hold more water than cold air. The Dew point is a measurement where the temperature should be when the water vapor it the air will start to condense and become liquid.