2024 Reflection of light simulation

$How does a lens or mirror form an image? See how light rays are refracted by a lens or reflected by a mirror. Observe how the image changes when you adjust the focal length of the lens, move the object, or move the screen. . Aletta ocean$

Total Internal Reflection. This 1.5-minute video features a demonstration in which a beam of light is directed into a hemicylindrical block of glass. The light approaches along the curved side of the cylinder along the radial line so that there is no refraction upon entering the block. Refraction occurs at the flat edge of the block. Reflection, refraction and diffraction are all boundary behaviors of waves associated with the bending of the path of a wave. The bending of the path is an observable behavior when the medium is a two- or three-dimensional medium. Reflection occurs when there is a bouncing off of a barrier. Reflection of waves off straight barriers follows the ...The subject of this chapter is the reflection and refraction of light—or electromagnetic waves in general—at surfaces. We have already discussed the laws of reflection and refraction in Chapters 26 and 33 of Volume I. Here’s what we found out there: The angle of reflection is equal to the angle of incidence. This app is a sort of tutorial which explains the reflection and the refraction of waves by the principle of Huygens. Explanations of each of the steps are provided in the text box. Whenever a step is finished, press the "Next step" button! You can stop and continue the simulation by using the "Pause / Resume" button.The angle of incidence in the water is approximately 39°. At this angle, the light refracts out of the water into the surrounding air bending away from the normal. The angle of refraction in the air is approximately 57°. These values for the angle of incidence and refraction are consistent with Snell's Law. S3P-2-07 Summarize the early evidence for Newton’s particle model of light. Include: propagation, reflection, refraction, dispersion S3P-2-08 Experiment to show the particle model of light predicts that the velocity of light in a refractive medium is greater than the velocity of light in an incident medium (vr > vi).Aug 4, 2020 · This is a 60 to 90 min. worksheet related to the concept of refraction and total internal reflection with simulations activities. Students can observe, examine, explore and connect the simulations to the concepts and would have a better understanding of the behaviour of the light rays in prisms with different shapes. Subject Physics The lighting simulation software is primarily used in illumination design to simulate and optimize light pipes, and light guides, and non-imaging lenses and mirrors. TracePro is also a powerful tool for analysis of aspects of imaging systems such as stray light analysis and polarization effects. With its full set of features, designers can ... Simulate the rays and images seen from some position. The blue circle is the observer. Any rays crossing it are considered to be "observed". The observer do not know where the rays actually begin, but may think they begin at some point (s) if they intersect there. The rays are shown in blue, and the point (s) in orange.until the wave theory of light was proposed. It is now well understood and experimentally veriﬁed that light travels more slowly through materials than through empty space. Air is mostly empty space, so the slowing down of light in air is very small and can be ignored in many cases. The index of refraction of a material is deﬁned as follows:The subject of this chapter is the reflection and refraction of light—or electromagnetic waves in general—at surfaces. We have already discussed the laws of reflection and refraction in Chapters 26 and 33 of Volume I. Here’s what we found out there: The angle of reflection is equal to the angle of incidence. The light ray reflecting away from the mirror is called the reflected ray. What is the Normal, Angle of Incidence and Reflection? A normal is a line drawn perpendicular to the reflective surface at the point where incident ray hits the surface.The law of reflection states that the angle of reflection (θ r) equals the angle of incidence (θ i), θ r = θ i (1) The normal, incident ray and reflected ray all lie in the same plane (Fig. 1). In this lab, you will study the image formation by plane mirrors using an online simulation (Fig. 2 below). Fig. 1: Reflection of light from a ...Light from the sun for example is composed of 7 distinct colors of light, and white light can be created with just three colors; blue, green and red light. Test your understanding and self-check Open the full B end i ng Li g ht simulation 6. Reflection, refraction and diffraction are all boundary behaviors of waves associated with the bending of the path of a wave. The bending of the path is an observable behavior when the medium is a two- or three-dimensional medium. Reflection occurs when there is a bouncing off of a barrier. Reflection of waves off straight barriers follows the ...Join photographer Nicholas on his expedition to Antarctica to photograph the wildlife. In this simulation, you will learn about the wave-like behaviors of light. When light travels from one medium into another, the rays can reflect off of the surface. Depending on the angle and the media, the light can also refract.This is a simulation to illustrate the processes involved in the formation of images in plane mirrors. When the control points are visible, you can move the object (the blue arrow), the four points where the (blue) incident rays strike the mirror, as well as the two ends of the mirror itself.REFLECTION AND REFRACTION SIMULATION. The purpose of this activity is to study how light reflects off a shiny surface, and how it refracts when entering a transparent material. Submit your answers using Blackboard. The angle of incidence and reflection are labeled i and r respectively.This pathway provides resources for understanding motion in one dimension. The fundamentals of vector and scalars are covered, and the key concepts of position, displacement, speed, velocity and acceleration are explained. The pathway concludes with a series of questions to test understanding of the topic. 6 Favorites.The light rays from an actual object bounce off the mirror to give a virtual image. With a flat mirror, the real object and the virtual object are symmetric and appear to be at the same distance on either side of the plane of the mirror. Symmetry rules at work in the reflection process explain how an image is formed by a plane mirror. Object A ... The Interactive consists of two parts. Part 1 is titled How do light rays reflect? This part introduces the law of reflection and addresses the manner in which light reflects off a plane mirror. Part 2 is titled How do images form in plane (flat) mirrors? This part investigates the interaction between light from the object and the observer's eye. Ellipse Reflection Model. Move the points. Adjust number of segments. Press Play. This is a computer model of how sound (or light, etc) reflects inside an ellipse. Points "F" and "G" are the focus points of the ellipse. Example: Stand at one focus point in an elliptical room. A friend could stand at the other focus point and whisper: you would ...https://phet.colorado.edu/sims/html/bending-light/latest/bending-light_en.htmloPhysics. Kinematics. Polarization of Light. Description. This is a simulation intended to help visualize polarization. A polarizing filter has a particular transmission axis and only allows light waves aligned with that axis to pass through. In this simulation unpolarized waves pass through a vertical slit, leaving only their vertical components. Apr 2, 2014 · Although light is an everyday phenomenon that we constantly observe, a numerous researches have reported that students often displayed learning difficulties and hold unscientific understanding on physics concepts of light wave. To address the situation, inquiry-based learning process with a support of computer simulation has been proved its benefits on development of student’s conceptual ... Although light is an everyday phenomenon that we constantly observe, a numerous researches have reported that students often displayed learning difficulties and hold unscientific understanding on physics concepts of light wave. To address the situation, inquiry-based learning process with a support of computer simulation has been proved its benefits on development of student’s conceptual ...The Plane Mirror Images Interactive is a skill-building tool that allows the user to explore the formation of images in plane mirrors. It makes a wonderful complement to lab activities on the law of reflection and the characteristics of plane mirror images. The Interactive takes a Tutorial approach to these topics.This is a simple simulation showing the reflection and refraction of a ray of light as it attempts to move from one medium to another. Use the sliders to adjust the index of refraction of each of the two materials, as well as the angle of incidence (the angle between the incident ray of light and the normal to the surface).How does a lens or mirror form an image? See how light rays are refracted by a lens or reflected by a mirror. Observe how the image changes when you adjust the focal length of the lens, move the object, or move the screen. Join photographer Nicholas on his expedition to Antarctica to photograph the wildlife. In this simulation, you will learn about the wave-like behaviors of light. When light travels from one medium into another, the rays can reflect off of the surface. Depending on the angle and the media, the light can also refract.The angle between the reflected ray and the normal is known as the angle of reflection. (These two angles are labeled with the Greek letter "theta" accompanied by a subscript; read as "theta-i" for angle of incidence and "theta-r" for angle of reflection.) The law of reflection states that when a ray of light reflects off a surface, the angle ...White light is made up of light rays with different wavelengths which we see as various colors. When light refracts, the amount of bending depends upon the light's wavelength. It is maximum for violet and minimum for red. Hence white light splits into different colored rays, each with different amount of bending, when passing through a prism. By converting our sims to HTML5, we make them seamlessly available across platforms and devices. Whether you have laptops, iPads, chromebooks, or BYOD, your favorite PhET sims are always right at your fingertips.Become part of our mission today, and transform the learning experiences of students everywhere! Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education <a {0}>research</a> and engage students through an intuitive, game-like environment where students learn through exploration and discovery.Bending Light Simulation Bend and Manipulate. Reflection and Refraction ... Details of Reflection and Refraction Demonstration Video. What is a Kaleidoscope? ...Total Internal Reflection. This 1.5-minute video features a demonstration in which a beam of light is directed into a hemicylindrical block of glass. The light approaches along the curved side of the cylinder along the radial line so that there is no refraction upon entering the block. Refraction occurs at the flat edge of the block. Simulate the rays and images seen from some position. The blue circle is the observer. Any rays crossing it are considered to be "observed". The observer do not know where the rays actually begin, but may think they begin at some point (s) if they intersect there. The rays are shown in blue, and the point (s) in orange.3D (using VR) Real image and virtual image Looking at an object, we feel there is an object in it. By the way, if you feel that there is something, we say there is an ‘image’, even if there is no real object... Search Simulations. 한국어.This is a simple simulation showing the reflection and refraction of a ray of light as it attempts to move from one medium to another. Use the sliders to adjust the index of refraction of each of the two materials, as well as the angle of incidence (the angle between the incident ray of light and the normal to the surface).REFLECTION AND REFRACTION SIMULATION. The purpose of this activity is to study how light reflects off a shiny surface, and how it refracts when entering a transparent material. Submit your answers using Blackboard. The angle of incidence and reflection are labeled i and r respectively.Hi Students and Teachers! Here is a tutorial on how to run the Reflection and Refraction Simulation. I hope this is helpful. Remember: This is Fine and I Can...How does a lens or mirror form an image? See how light rays are refracted by a lens or reflected by a mirror. Observe how the image changes when you adjust the focal length of the lens, move the object, or move the screen.In this activity students will be exploring reflection of light in a plane mirror using the “Bending Light” PhET simulation. Open the simulation by clicking on the link:Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So if the media (or its properties) are changed, the speed of the wave is changed. Thus, waves passing from one medium to another will undergo refraction. Refraction of sound waves is most evident in situations in which the sound ...Reflection of light (and other forms of electromagnetic radiation) occurs when the waves encounter a surface or other boundary that does not absorb the energy of the radiation and bounces the waves away from the surface. The simplest example of visible light reflection is the surface of a smooth pool of water, where incident light is reflected ... The Plane Mirror Images simulation blends an interactive Tutorial with an interactive simulation. Students will learn about the law of reflection and how it can be used to determine the location and characteristics of an image formed by a plane mirror.Polarized light waves are light waves in which the vibrations occur in a single plane. The process of transforming unpolarized light into polarized light is known as polarization. There are a variety of methods of polarizing light. The four methods discussed on this page are: Polarization by Transmission.Lay the mirror flat on the table with the shiny side up. Hold the flashlight at an angle pointing down toward the mirror. Explain to students that the light will be reflected off the mirror. Their task is to use the construction paper to catch the reflected light in order to pinpoint exactly where it goes.A. Reflection of Light Rays (Review section 28.2 of text). What is not commonly known is that light incident upon a transparent medium (of a different refractive index) will be both refracted and reflected. The reflected light obeys the law of reflection. See figure below from PhET simulation. Figure 18-1cal simulation of light scattering by multiple wavelength-sized particles near or between planar interfaces. It im-plements the superposition T-matrix method [15, 16, 17] Krzysztof Czajkowski and Dominik Theobald contributed equally to this work. Figure 1: Artistic visualization of a Gaussian beam scattered by multiple particles on a substrate. In this video You will learn the basics of refraction of light. Here the concept of total internal reflection (TIR) and Critical Angle has also been discusse... https://phet.colorado.edu/sims/html/bending-light/latest/bending-light_en.htmlFounded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education <a {0}>research</a> and engage students through an intuitive, game-like environment where students learn through exploration and discovery.Aug 25, 2022 · Conclusion: when light passes from a transparent medium A to another transparent medium B where n A > n B: 1. if then refraction will take place. 2. if then the refraction angle is 90° (grazing angle). if then total internal reflection will take place and (where is the angle of reflection and not refraction). oPhysics. Select a simulation from one of the above categories or click on a category to see descriptions of the simulations for that category. Hydrogen Energy Levels. This is a simulation of an atomic energy level diagram of the hydrogen atom.The phenomenon observed in this part of the lab is known as total internal reflection. Total internal reflection, or TIR as it is intimately called, is the reflection of the total amount of incident light at the boundary between two media. TIR is the topic of focus in Lesson 3. To understand total internal reflection, we will begin with a ...This is a simple simulation showing the reflection and refraction of a ray of light as it attempts to move from one medium to another. Use the sliders to adjust the index of refraction of each of the two materials, as well as the angle of incidence (the angle between the incident ray of light and the normal to the surface). Convex Mirror Images. The Convex Mirror Image Formation Interactive provides learners with a virtual light box for exploring the reflection of light off convex mirrors and the manner in which such reflection leads to the formation of an image of a complex object. Learners tap on various points upon an object. A ray diagram is quickly ... Reflection and Refraction of Light. A ray of light coming from the top left strikes the boundary surface of two media. (It is possible to choose the substances in both lists.) The medium which has the bigger index of refraction is painted blue, the other yellow. You can vary the incident ray with pressed mouse button.In this video You will learn the basics of refraction of light. Here the concept of total internal reflection (TIR) and Critical Angle has also been discusse... The Plane Mirror Images Interactive is a skill-building tool that allows the user to explore the formation of images in plane mirrors. It makes a wonderful complement to lab activities on the law of reflection and the characteristics of plane mirror images. The Interactive takes a Tutorial approach to these topics.The Plane Mirror Images Interactive is a skill-building tool that allows the user to explore the formation of images in plane mirrors. It makes a wonderful complement to lab activities on the law of reflection and the characteristics of plane mirror images. The Interactive takes a Tutorial approach to these topics.24. Look at the surface where the light exits from the material to the air, as you change the color of the ray of light from blue toward red, how does the refracted angle change? Select white light and dark background by clicking the last icon on: 25. What is the name of the physical phenomenon effecting the white light that you are observing ?The refractive index is a property of a medium through which light can pass. Its value is calculated from the ratio of the speed of light in vacuum to that in the medium. For example, the refractive index of glass is 1.516 and that of water is 1.333. The amount of bending of light during refraction depends on the difference between the ...Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So if the media (or its properties) are changed, the speed of the wave is changed. Thus, waves passing from one medium to another will undergo refraction. Refraction of sound waves is most evident in situations in which the sound ...lack of medium) for light, 𝑣<𝑐 for anything that isn’t vacuum. This means that 𝑛>1, and the larger 𝑛 is, the slower light travels through the medium. In the third video, green laser light passes from air to a piece of acrylic. The index of refraction for the acrylic is 3) (1 point) Calculate the speed of light 𝑣 as it travels Simulate the rays and images seen from some position. The blue circle is the observer. Any rays crossing it are considered to be "observed". The observer do not know where the rays actually begin, but may think they begin at some point (s) if they intersect there. The rays are shown in blue, and the point (s) in orange.Hi Students and Teachers! Here is a tutorial on how to run the Reflection and Refraction Simulation. I hope this is helpful. Remember: This is Fine and I Can...The Plane Mirror Images simulation blends an interactive Tutorial with an interactive simulation. Students will learn about the law of reflection and how it can be used to determine the location and characteristics of an image formed by a plane mirror.Explore bending of light between two media with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows. Explore bending of light between two media with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows. By converting our sims to HTML5, we make them seamlessly available across platforms and devices. Whether you have laptops, iPads, chromebooks, or BYOD, your favorite PhET sims are always right at your fingertips.Become part of our mission today, and transform the learning experiences of students everywhere! You can explore the color appearance of a person and of the shadows creating by that person on a white screen with our Colored Shadows simulation. Filtering Away. A color filter is a transparent film that absorbs a range of wavelengths of light. Looking at the world through a color filter will change the color appearance of objects.In/Post-Class Activity, Bending Light, PhET. Description. This is a 60 to 90 min. worksheet related to the concept of refraction and reflection with conceptual questions and simulations activities. Students can observe, examine, explore and connect the simulations to the concepts and would have a better understanding of bending/refracting light ...White light is made up of light rays with different wavelengths which we see as various colors. When light refracts, the amount of bending depends upon the light's wavelength. It is maximum for violet and minimum for red. Hence white light splits into different colored rays, each with different amount of bending, when passing through a prism. Seen by observer. Simulate the rays and images seen from some position. The blue circle is the observer. Any rays crossing it are considered to be "observed". The observer do not know where the rays actually begin, but may think they begin at some point (s) if they intersect there. The rays are shown in blue, and the point (s) in orange.Jul 21, 2020 · In/Post-Class Activity, Bending Light, PhET. Description. This is a 60 to 90 min. worksheet related to the concept of refraction and reflection with conceptual questions and simulations activities. Students can observe, examine, explore and connect the simulations to the concepts and would have a better understanding of bending/refracting light ... Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education <a {0}>research</a> and engage students through an intuitive, game-like environment where students learn through exploration and discovery.Description. This is a visual simulation of the reflection of a wave pulse. Use the check boxes choose between a fixed end (bouncing off a more rigid medium) or a free end (bouncing off a less rigid medium). Use the other check boxes to show or hide the undisturbed incident and reflected waves, so that you can see how their superposition causes ... Explore bending of light between two media with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows.Sample Learning Goals. Explain how light bends at the interface between two media and what determines the angle. Apply Snell’s law to a laser beam incident on the interface between media. Describe how the speed and wavelength of light changes in different media. Describe the effect of changing wavelength on the angle of refraction.The Interactive consists of two parts. Part 1 is titled How do light rays reflect? This part introduces the law of reflection and addresses the manner in which light reflects off a plane mirror. Part 2 is titled How do images form in plane (flat) mirrors? This part investigates the interaction between light from the object and the observer's eye. Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education <a {0}>research</a> and engage students through an intuitive, game-like environment where students learn through exploration and discovery.lack of medium) for light, 𝑣<𝑐 for anything that isn’t vacuum. This means that 𝑛>1, and the larger 𝑛 is, the slower light travels through the medium. In the third video, green laser light passes from air to a piece of acrylic. The index of refraction for the acrylic is 3) (1 point) Calculate the speed of light 𝑣 as it travels Description. This is a visual simulation of the reflection of a wave pulse. Use the check boxes choose between a fixed end (bouncing off a more rigid medium) or a free end (bouncing off a less rigid medium). Use the other check boxes to show or hide the undisturbed incident and reflected waves, so that you can see how their superposition causes ... Join photographer Nicholas on his expedition to Antarctica to photograph the wildlife. In this simulation, you will learn about the wave-like behaviors of light. When light travels from one medium into another, the rays can reflect off of the surface. Depending on the angle and the media, the light can also refract.

Aug 4, 2020 · This is a 60 to 90 min. worksheet related to the concept of refraction and total internal reflection with simulations activities. Students can observe, examine, explore and connect the simulations to the concepts and would have a better understanding of the behaviour of the light rays in prisms with different shapes. Subject Physics . Avatar the way of water showtimes near regal dania pointe

Reflection from a Mirror. Update your browser! Adjust the angle of the mirror and see what happens to the reflected beam! Determine the angle when each observer can see the light. Simulation created Steven Sahyun, University of Wisconsin - Whitewater using code modified from Andrew Duffy's Friction on an incline simulator. December 19, 2018.Sample Learning Goals. Explain how light bends at the interface between two media and what determines the angle. Apply Snell’s law to a laser beam incident on the interface between media. Describe how the speed and wavelength of light changes in different media. Describe the effect of changing wavelength on the angle of refraction.lack of medium) for light, 𝑣<𝑐 for anything that isn’t vacuum. This means that 𝑛>1, and the larger 𝑛 is, the slower light travels through the medium. In the third video, green laser light passes from air to a piece of acrylic. The index of refraction for the acrylic is 3) (1 point) Calculate the speed of light 𝑣 as it travelsThe manner in which light is reflected from a surface depends on the surface’s smoothness. Light that is reflected from a rough, textured surface, such as paper, cloth, or unpolished wood, is reflected in many different directions, as shown in Fig 1(a). This type of reflection is called diffuse reflection.Explore bending of light between two media with different indices of refraction. See how changing from air to water to glass changes the bending angle. Play with prisms of different shapes and make rainbows.Apr 2, 2014 · Although light is an everyday phenomenon that we constantly observe, a numerous researches have reported that students often displayed learning difficulties and hold unscientific understanding on physics concepts of light wave. To address the situation, inquiry-based learning process with a support of computer simulation has been proved its benefits on development of student’s conceptual ... This is Snell's law, also known as Descarte’s Law, or The Law of Refraction. When light passes from one medium to another, some of this light is reflected while another part penetrates into the medium with a change in its direction. These two phenomena are called the reflection and refraction of light. The angle of reflection of a ray of ...Lay the mirror flat on the table with the shiny side up. Hold the flashlight at an angle pointing down toward the mirror. Explain to students that the light will be reflected off the mirror. Their task is to use the construction paper to catch the reflected light in order to pinpoint exactly where it goes.Welcome to Ray Optics Simulation. To add an optical component, select a tool and click the blank space. To load an example, please go to the Gallery page. File: Undo Redo Reset Save Open Export Get Link View Gallery. Tools: Ray Beam Point source Blockers Mirrors Glasses Ruler Protractor Detector Text Move view. View:How does a lens or mirror form an image? See how light rays are refracted by a lens or reflected by a mirror. Observe how the image changes when you adjust the focal length of the lens, move the object, or move the screen.Bending of light Objective: The objectives of this lab activities are : To study the law of reflection and refraction of light using different media To study the phenomenon and condition of total internal reflection To observe the dispersion of light by prism and refraction of light by different kinds of lens Introduction: The law of reflection of light states that when light bounces off from ... Bending of light Objective: The objectives of this lab activities are : To study the law of reflection and refraction of light using different media To study the phenomenon and condition of total internal reflection To observe the dispersion of light by prism and refraction of light by different kinds of lens Introduction: The law of reflection of light states that when light bounces off from ...How does a lens or mirror form an image? See how light rays are refracted by a lens or reflected by a mirror. Observe how the image changes when you adjust the focal length of the lens, move the object, or move the screen. S3P-2-07 Summarize the early evidence for Newton’s particle model of light. Include: propagation, reflection, refraction, dispersion S3P-2-08 Experiment to show the particle model of light predicts that the velocity of light in a refractive medium is greater than the velocity of light in an incident medium (vr > vi).Light from the sun for example is composed of 7 distinct colors of light, and white light can be created with just three colors; blue, green and red light. Test your understanding and self-check Open the full B end i ng Li g ht simulation 6.This is a simple simulation showing the reflection and refraction of a ray of light as it attempts to move from one medium to another. Use the sliders to adjust the index of refraction of each of the two materials, as well as the angle of incidence (the angle between the incident ray of light and the normal to the surface).PhET waves intro has three animations that link to water waves, sound and light and introduce the terms frequency and amplitude. The water wave animation can also be used to replicate part of the GCSE waves required practical. Measuring the wavelength and speed of water waves using method 2 (can be done using baking trays or other suitable ...Bending Light Simulation Bend and Manipulate. Reflection and Refraction ... Details of Reflection and Refraction Demonstration Video. What is a Kaleidoscope? ...The Plane Mirror Images Interactive is a skill-building tool that allows the user to explore the formation of images in plane mirrors. It makes a wonderful complement to lab activities on the law of reflection and the characteristics of plane mirror images. The Interactive takes a Tutorial approach to these topics. Ellipse Reflection Model. Move the points. Adjust number of segments. Press Play. This is a computer model of how sound (or light, etc) reflects inside an ellipse. Points "F" and "G" are the focus points of the ellipse. Example: Stand at one focus point in an elliptical room. A friend could stand at the other focus point and whisper: you would ... .

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