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Optics and Algebra - Contenido educativo

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Connect Segment explaining optics and the use of algebra in optics. Describes focal length, reflector telescope, and mirrors.

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What is optics, and how is algebra used in optics? 00:00:00
Optics is the study of light, what it is, how it moves through space, and how it interacts 00:00:07
with objects. 00:00:13
Light can be controlled with lenses and mirrors, and these elements can be combined into optical 00:00:14
instruments like telescopes, lasers, and cameras, just like the one being used to take this 00:00:19
picture now. 00:00:25
There are two types of telescopes. 00:00:26
This is a refractor telescope that has a lens in the front. 00:00:28
This is a reflector telescope that has no lens, but a mirror in the bottom of it. 00:00:32
The light from the object goes through the tube, is concentrated by the mirror, to form 00:00:37
an image which I see with my eye. 00:00:42
Reflector telescopes are better for looking at faint objects like distant stars, and are 00:00:45
therefore better for astronomy. 00:00:49
I've taken this mirror out of a telescope to show you how the light is focused down 00:00:51
to a spot at the focal point. 00:00:56
This distance from the spot to the mirror is called the focal length, and there's an 00:00:59
algebraic expression that relates the distance of the focal length, the distance u, to an 00:01:04
object, and the distance v to the image formed by the mirror. 00:01:10
That expression is 1 over f is equal to 1 over v plus 1 over u. 00:01:15
We use this equation to test telescopes here at the X-ray Calibration Facility. 00:01:19
We want to have the object source as far away from the telescope as possible, so we 00:01:24
put it at the end of this tunnel, which is a third of a mile, or 500 meters away. 00:01:28
Then, with the telescope at the other end, we measure the image formed by the mirror 00:01:33
very precisely, to make sure that the telescope is built properly, and will focus the stars 00:01:37
correctly. 00:01:42
And that's how we use algebra in optics. 00:01:43
Ground-based telescopes have revealed much over their nearly 400-year history, but they're 00:01:47
really limited in what they can show us. 00:01:53
Things like light pollution, cloud cover, and the Earth's turbulent atmosphere interfere 00:01:56
with ground-based telescope observations. 00:02:01
So in 1990, NASA launched the Hubble Space Telescope, an automated reflecting telescope 00:02:04
which orbits the Earth every 97 minutes. 00:02:10
The Hubble Telescope was named after Edwin Hubble, who discovered that the universe is 00:02:13
expanding, and the more distant a galaxy, the faster it appears to move away. 00:02:17
Remember the graph we analyzed at the beginning of the show? 00:02:22
Well, Hubble created a graph that's not too different from our pizza graph. 00:02:25
Check it out. 00:02:29
Hubble's graph shows a linear relationship between distance and velocity. 00:02:31
Remember the linear equation we used for the pizza graph, n times 2 equals p? 00:02:36
Well, the linear equation for Hubble's graph is h times d equals v. h is the Hubble constant. 00:02:41
It is similar to the number 2 in our previous equation. 00:02:48
Remember there were two servings and one pizza? 00:02:52
Anyway, d is the distance of the object, and v is the velocity, or speed, of the object. 00:02:54
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Idioma/s:
en
Materias:
Matemáticas
Niveles educativos:
▼ Mostrar / ocultar niveles
      • Nivel Intermedio
Autor/es:
NASA LaRC Office of Education
Subido por:
EducaMadrid
Licencia:
Reconocimiento - No comercial - Sin obra derivada
Visualizaciones:
259
Fecha:
28 de mayo de 2007 - 16:52
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
03′ 01″
Relación de aspecto:
4:3 Hasta 2009 fue el estándar utilizado en la televisión PAL; muchas pantallas de ordenador y televisores usan este estándar, erróneamente llamado cuadrado, cuando en la realidad es rectangular o wide.
Resolución:
480x360 píxeles
Tamaño:
18.21 MBytes

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