Week 7 - Grade 8 Light Energy PDF

Day 1: lesson 3: Light waves  Objectives  Define light  Describe light wave as electromagnetic (EM)wave  Explain the stages how EM waves are formed  Design 3d...

Day 1: lesson 3: Light waves  Objectives  Define light  Describe light wave as electromagnetic (EM)wave  Explain the stages how EM waves are formed  Design 3d model of EM waves Essential question : what is light?  Vocabularies Light Electromagnetic waves Radiation  The Nature of Light Light is a type of energy that travels as wave. A light bulb, a burning log, a candle, fireflies and some fish produce light (i.e they are sources of light). Light is different from other kinds of waves. Other kinds of waves, like sound waves and water waves, must travel through matter. Light does not require matter(medium) through which to travel. Because electric and magnetic fields can exist in empty space, EM waves do not need a medium in which to travel. Light is an electromagnetic (EM) wave. EM waves have two parts. These are electric and magnetic fields. What patterns do you observe? How are the two waves similar? How are they different The stages (Electric and Magnetic fields) forming EM waves When an electrically charged particle vibrates, it disturbs the electric and magnetic fields around it. These two vibrating fields produce EM waves. The fields are perpendicular to each other and carry energy away from the charged particles  Group Activity: Design 3d model of EM waves Materials: scissor, 2 hard papers, colored markers, ruler. Instructions: - Draw 2 or 3 waves in each paper using different colors representing magnetic and electric waves. - All waves should have the same length (1 cm). - Cut half the papers from one side along with the rest position of each waves, but do not split. - Cross the waves perpendicularly. - Make sure that the waves are connected and oscillating. - Watch the video for more instructions. Day 2: lesson 3: Light waves  Objectives  Identify the different waves found in electromagnetic spectrum.  Explain the relationship between wavelength, frequency, and energy.  Compare and contrast the different Em waves.  Relate the electromagnetic spectrum to everyday life and modern technology. Essential question : what is light? Starter: Draw in your copybook EM waves – Light waves – showing 2 fields (magnetic and electric).  EM spectrum ▪ The electromagnetic spectrum is a range of waves with different frequencies and energies. ▪ Different types of waves have various uses, from communication to medical treatments. Watch the video and Identify the different waves found in EM spectrum. Checking understanding Order the EM spectrum from the highest to the lowest frequency/ energy (descending). Gamma Ultraviolet X-rays rays UV Visible light Radio Microwaves Infrared waves Watch the video and Explain the relationship between wavelength, frequency, and energy. From the video: How do radio waves help with communication? Why is visible light essential for life on Earth? How can ultraviolet light both help (vitamin D) and harm (sunburn)? How do x-rays help doctors?  Radio Waves: EM spectrum from lowest Longest wavelength, lowest frequency and energy. energy to highest Example: Communication signals (TV, radio), cell phones. Ultraviolet (UV) Radiation: Higher frequency than visible light, Microwaves: just below x-rays. Shorter  than radio waves but still Example: Sunburns, sterilizing long. medical equipment. Example: Microwave ovens, satellite communications. X-rays: Higher energy than UV. Infrared (IR) Radiation: Example: Medical imaging (X- Just below visible light in frequency. rays). Example: Heat lamps, night vision goggles. Gamma Rays: Shortest wavelength, highest Visible Light: energy. The only part of the EM spectrum we Example: Used in cancer can see with our eyes. treatment, emitted by radioactive Example: Rainbow colors materials. (ROYGBIV), sunlight. Check your understanding Compare and contrast the different Em waves and Relate them to everyday life and modern technology. Each student should write at least one use for 2 waves DAY 3 - LESSON 2: LIGHT WAVES AND COLOR ► MS-PS4-1 Use mathematical representations to describe a simple model for waves that includes how the amplitude of waves is related to the energy in a wave ►Standards: ► MS-PS4-2 Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials   State that color corresponds to certain wavelength and frequency of light ►Objectives  Describe the light colors in rainbow  Explain why the rainbow colors are always like that (in order)  Compare how different colors of light wave are arranged  ▪ Color ►Vocabulary ▪ White light ▪ Visible light  Instructions: Group work - Sit in your group - Choose your role / pick your (Research Skills) role - Search for the information - Present 1.What is a visible light? 2. How is a visible light separated into many colors? 3. what separates the White color into different colors?  ▶ Light travels as wave, which are invisible to us because their wavelength are too short or too long for human eyes ▶ Light that can be sensed by our eyes is visible light ▶ Visible light consist of a continuous range of wavelengths or frequencies ▶ Waves in the visible range appear to us a spectrum of colors LIGHT WAVES ▶ Each color corresponds to a certain wavelength and AND COLOR frequency of light ▶ Our eyes interpret these different wavelengths as different colors Light traveling through prism The glass prism refract the white light differently? What can you say about the refraction of different colors through the prism? Time to discuss Which color of light bends more than the others? Violet ROY G BIV Think- The correct order of visible light Pair- colors Ascendingly Share (shorter to longer wavelength) Red Orange Yellow Green Violet Indigo Blue What determines the color of light ? ▶ Sun light contains all wavelength of visible light ▶ The wavelength and frequency of visible light determines its color Q. Which light color are in the shorter wavelength and which light colors are in the longer wavelength? (use the picture below) CHECK YOUR UNDERSTANDING ▶ Color corresponds to certain ____________ and ________of light ▶ Answer wavelength and frequency  Color is the perceptual of quality of light ▶ What can you say about the color of light and their respective frequency?