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Mirrors, Reflection, and Refraction
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NASA Why? Files segment exploring the way light bends and bounces.
Hi. I'm Michelle Shin. Welcome to the Department of Energy's Jefferson Lab.
00:00:00
Hi, Dr. Shin. This is a neat looking place. What do you do here?
00:00:09
Well, I'm a laser physicist. That's a scientist who studies and makes different kinds of lasers and uses them to hit different objects.
00:00:13
Lasers? Like in Star Wars?
00:00:20
Well, sort of like that. So anyway, what can I help you with today?
00:00:23
We were using mirrors this morning and noticed that light bounced around the room.
00:00:27
We want to know more about how light bounces.
00:00:31
Well, I'd be happy to answer that for you, Bianca.
00:00:34
Light that bounces off a surface is called reflective light. The type of surface determines the kind of reflection you get.
00:00:37
A mirror is really shiny. Does that make a difference?
00:00:44
It makes a big difference. If the surface is shiny, then the image you see looks just like the object.
00:00:47
So a surface that is not shiny and smooth will scatter light?
00:00:53
That's right. You catch on really fast.
00:00:57
Does light only reflect?
00:00:59
No. Light also refracts.
00:01:01
What does refractive mean?
00:01:03
Well, Bianca, I think it's easiest to show you.
00:01:05
Okay, Bianca, we need to put on some gloves and goggles because you're going to work with some liquid nitrogen.
00:01:08
We use these in science.
00:01:13
Good. It helps to be safe when you're doing experiments.
00:01:14
What's that stuff bubbling?
00:01:17
It's liquid nitrogen. We're going to use the vapor to explore reflection and refraction.
00:01:19
So, Bianca, this is a laser, and I'm going to shine it on the gelatin.
00:01:24
But first, I need to have you dim the lights.
00:01:27
What I'm going to do now is shine it on the gelatin. Look closely and tell me what you see.
00:01:32
I see the light coming up into the gelatin. That must be reflection.
00:01:36
Right.
00:01:40
But the light is also being bent. Why is that?
00:01:41
Well, when light travels from one medium, such as air, to another medium, such as gelatin, its speed changes.
00:01:44
And when the speed changes, the light bends, and we call that light refraction.
00:01:52
Does the speed of light speed up or slow down when it's going through the gelatin?
00:01:57
Well, because the gelatin is thicker than air, it slows down.
00:02:01
I wonder if magicians create some of their magic with mirrors.
00:02:04
This is a concave mirror. It curves inwards, and you can see that your image, if I hold it in one way, is upright.
00:02:08
And as I get closer, it gets inverted. It turns upside down.
00:02:15
That would be an easy way to stand on your head.
00:02:18
It really would.
00:02:21
This is a convex lens. You can see that the surface curves outwards.
00:02:22
And as you look at it, you look much smaller.
00:02:27
And another place that uses lenses and mirrors is NASA.
00:02:30
NASA needs mirrors and lenses for their big telescopes.
00:02:34
Space telescopes like the Hubble Telescope or the Mars Global Surveyor or the GOES weather satellites.
00:02:37
That's cool. Thanks, Dr. Shin. Bye.
00:02:46
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- Idioma/s:
- 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:
- 372
- Fecha:
- 28 de mayo de 2007 - 15:32
- Visibilidad:
- Público
- Enlace Relacionado:
- NASAs center for distance learning
- Duración:
- 02′ 50″
- 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:
- 17.11 MBytes
