Energy from the Sun that reaches Earth by waves through space Types of solar radiation: •Visible light range of the ultraviolet spectrum •Infrared radiation •Ultraviolet radiation Visible light range of the ultraviolet spectrum Cones in our eyes are receivers for these tiny visible light waves. The Sun is a natural source for visible light waves and our eyes see the reflection of this sunlight off the objects around us. The color of an object that we see is the color of light reflected. All other colors are absorbed. A visible light picture (left) and an infrared picture (right) of two cups. One cup contains cold water, while the other contains hot water. In the visible light picture we cannot tell, just by looking, which cup is holding cold water and which is holding hot water. In the infrared image, we can clearly "see" the glow from the hot water in the cup to the left and the dark, colder water in the cup to the right. If we had infrared eyes, we could tell if an object was hot or cold without having to touch it. http://coolcosmos.ipac.caltech.edu/cosmic_kids/learn_ir/index.html Above are infrared images of a warm-blooded dog (left) and of a warmblooded human holding a cold-blooded caterpillar (right). Warm-blooded animals, like the dog shown above, make their own heat. In the infrared picture you can see how the dog's fur keeps some of this heat from escaping, keeping the dog warm. Insects are cold-blooded, which means that they cannot make their own body heat. Instead they take on the temperature of their surroundings. The cold-blooded caterpillar appears very dark (cool) in the infrared compared to the warm-blooded human who is holding it. Notice how the caterpillar is at about the same temperature as the surrounding air. Another interesting fact about infrared light is that it can travel through thick smoke, dust or fog, and even some materials. http://coolcosmos.ipac.caltech.edu/cosmic_kids/learn_ir/index.html Infrared radiationlonger waves that warm the Earth Although infrared radiation is not visible, humans can sense it - as heat. Put your hand next to a hot oven if you want to experience infrared radiation "first-hand! shorter waves than visible light waves that interact with skin to cause sunburn What effect does solar radiation have on Earth’s oceans? It warms the water. Plants use the sun’s energy through photosynthesis What energy changes take place during photosynthesis? Plants change light energy from the sun into chemical energy Animals use the sun’s energy in the food chain Humans use the sun’s energy to run machines with fossil fuel Humans use the sun’s energy for electricity Earth’s temperatures are affected by: •Where the sunlight hits the Earth •Interaction with the atmosphere Landforms and oceans absorb 51% of solar radiation Earth, in turn, gives off infrared radiation Clouds and gasses absorb this heat and send it back to Earth’s surface The way in which Earth’s atmosphere traps and stores energy near the Earth’s surface Why is the sky blue? Because of: • Visible light • Each wave of color has a different length • Red longest • Blue shortest • Particles in the atmosphere absorb and scatter blue waves OR……………………… Sunlight collides with air, scatters blue wavelengths. Caused by the tilting of the hemispheres toward the sun • Driven by solar radiation • Water absorbs solar radiation • Energy causes water to evaporate and turn to water vapor. This is less dense than water and it rises. • Water vapor condenses around dust particles • Turns to tiny droplets of water that become clouds • Fall as rain or snow • Runs off or becomes groundwater • Plants absorb water • It goes to leaves and absorbs solar energy • Evaporates • Cycle continues Oceans • 97% of Earth’s water is in oceans • Oceans cover 70% of Earth’s surface The waters of the oceans move in currents. Warm water flows from Equator to poles. Cooler water flows to the Equator. Convection, tides and winds affect the movement. Convection Current • Cold water in the Atlantic sinks under warmer water then moves south, circles Antarctica, then moves northward. • Water is heated by thermal vents in the ocean floor. It rises to the surface, loses heat energy to the atmosphere and cools. • This cool water sinks and the cycle continues. Surface Currents • California Current • Takes cold water from the North Pole, flows south and helps keep weather cooler. • Gulf Stream • Picks up warm weather from the Equator and flows northeast along the east coast. California Current Gulf Stream Coastal Eddies •Run in opposite direction from a main current •Source of nutrients for sea life Thermal gradient A gradual increase or decrease in temperature over a distance Example- from the North Pole to the Equator Air pressure •Air pressure is the force exerted on you by the weight of tiny particles of air (air molecules). •Differences in air pressure are caused by uneven heating of Earth’s surface. •http://kids.earth.nasa.gov/archive/ air_pressure/spin.html •http://kids.earth.nasa.gov/archive/ air_pressure/barometer.html Wind •Hot air rises •Leaves an area of low pressure •As it moves, it cools •Molecules get closer together and the pressure increases •Air moves from areas of high pressure to low pressure A difference in air pressure is what causes the wind to blow. Wind is simply air moving from a place of high air pressure to a place of low air pressure. The greater the difference in air pressure, the stronger the winds. Convection Air Currents are affected by •Uneven heating of Earth’s surface •Geography of the land •Earth’s rotation Coriolis Effect •Change in direction of a freely moving object, caused by the Earth’s rotation •Responsible for circular motion of many weather patterns •Earth’s rotation •http://www.baesi.org/TRG/coriolis/CORIOLIS. MOV •Rock so hot that it can flow like taffy or syrup •Heat from the Earth’s core (12,000ºF) causes the rocks to heat those above them •This heat moves by convection •When the hot rock reaches the lithosphere, it spreads out. •The rock cools, then sinks back down. •The cycle continues. •These currents can force the plates to move, causing mountains to form, volcanoes to erupt, and continents to change shape. Unlike climate, weather can change quickly. The exchange of energy between air and ocean currents is a cause of this change. Weather Changes •Thunderstorms •Hurricanes •Waterspouts •Atmospheric Edd Air masses •Maritime- over water •Continental- over land In California •Polar maritime •Tropical maritime Air masses cause a change in air pressure which leads to a change in weather. Humidity is the amount of water vapor in the air Relative Humidity The ratio of the actual amount of water vapor in air to the possible amount that the air could contain. Warm air masses can hold more than cold. Fronts •Cold front- cold air mass moves toward an area of warmer air usually causes steady rain •Warm front- warm air mass moves toward an area of colder air, usually causes heavy rain •Stationary front- when two air masses meet and are not moving, usually causes a long period of precipitation