California science grade 5 (9)

CHAPTER Energy in the Earth System How radiation and convection currents affect phenomena on Earth? 212 Lesson Electromagnetic Spectrum PAGE 216 Lesson Solar Radiation PAGE 228 Lesson The Power of Convection Currents PAGE 240 PS Many phenomena on Earth’s surface are affected by the transfer of energy through radiation and convection currents 213 Literature MAGAZINE ARTICLE ELA R 6.2.2 Analyze text that uses the compare-andcontrast organizational pattern • ELA W 6.2.2 Write expository compositions (e.g., description, explanation, comparison and contrast, problem and solution) 214 from MONKEYSHINES ON HEALTH AND SCIENCE A Scientific Breakthrough Most light, whether from a candle or a high-powered spotlight, is composed of many different colors and quickly spreads over a wide area as it travels away from its source Laser light, however, can be concentrated into a very fine line which can travel thousands of miles unless something blocks it Lasers, invented in the early 1950s, have revolutionized communications, astronomy, surgery, and a multitude of other scientific fields A laser is a specialized lamp producing light waves which are extremely bright, are pure in color, and can be highly focused Light, television, and radio signals are all forms of electromagnetic waves Microwaves, like those used to cook food in microwave ovens, are a few inches long Dr Charles Townes of New York’s Columbia University invented a way to amplify and transmit microwaves in 1954, calling it a maser, short for “microwave amplification by the stimulated emission of radiation.” Lasers consist of four basic parts: an energy source, an active medium, an amplification system, and an output unit Many lasers are made using crystal rubies, but lasers also can be made using various gases and liquids Many recent laser designs incorporate the same kinds of semiconductor materials found in computer microchips As laser research continues and industry continues to develop new laser applications, lasers probably will come to play an even greater role in our everyday lives Write About It Response to Literature In this article the author tells about the invention of the laser How did this invention come about? What impact has it had on science? Write an essay comparing and contrasting lasers and other forms of light What they have in common? How they differ? -Journal Write about it online @ www.macmillanmh.com 215 Lesson Electromagnetic Spectrum A rainbow appears when falling raindrops bend sunlight Like a prism, each raindrop divides white light into bands of different colors—the part of the electromagnetic spectrum people can see There are other parts that people cannot see Parts of the electromagnetic spectrum warm the air on a hot day 216 ENGAGE PS 3.d Students know heat energy is also transferred between objects by radiation (radiation can travel through space) • ES 4.b Students know solar energy reaches Earth through radiation, mostly in the form of visible light Materials Which material best heats water? Make a Prediction Which material—white paper, black construction paper, or aluminum foil—will most quickly raise the temperature of water when placed in direct sunlight? Write your answer as a prediction in the form “If I wrap three jars using white paper, black construction paper, and aluminum foil, then ” • medium-size jars Test Your Prediction • black construction paper Experiment Fill three jars with the same amount of water Wrap one of the materials around each jar, and secure each with a piece of tape Place the jars on a level surface in a location that receives direct sunlight Place a thermometer in each jar, and stir the water Record the temperature of the water in each jar Wait 30 minutes, stir the water, and record the temperature of the water in each jar again • white paper • aluminum foil • tape • thermometers Step Draw Conclusions Use Numbers For each jar, subtract the initial temperature of the water from the temperature recorded after 30 minutes in the sunlight In which jar was the temperature of the water most increased? Was your prediction correct? Infer What caused the water temperature in the jars to rise? Step Explore More Set the jars in a place that does not receive direct sunlight Which jar will lose the most heat? Wait 30 minutes, stir the water, and record the temperature Which jar lost the most heat? Analyze the data and present your results IE 7.d Communicate the steps and results from an investigation in written reports and oral presentations • IE 7.e Recognize whether evidence is consistent with a proposed explanation 217 EXPLORE ▶ Main Idea PS 3.d ES 4.b Heat travels from the Sun to Earth by radiation in the form of electromagnetic waves ▶ Vocabulary electromagnetic spectrum, p 218 radiation, p 220 absorption, p 220 emission, p 221 -Glossary @ www.macmillanmh.com ▶ Reading Skill Sequencing 4W`ab What is the electromagnetic spectrum? The Sun’s energy is carried to Earth by electromagnetic waves The electromagnetic spectrum is the wide range of electromagnetic radiation ordered by wavelength A wavelength is the distance along a wave before it repeats Shorter wavelengths have higher energy, while longer wavelengths have lower energy The electromagnetic spectrum, arranged from waves with the lowest amount of energy to waves with the highest amount of energy, consists of radio waves, microwaves, infrared rays, visible light, ultraviolet light, X rays, and gamma rays Radio waves have the longest wavelengths and include transmissions of AM radio, shortwave radio, TV, and FM radio Microwaves, used to power radar and satellite systems, as well