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Simple Machines
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NASA Sci Files segment explaining how simple machines affect energy transfer.
Hi, our friend Jacob just broke his foot, and he is learning a little bit about what it is like to be disabled.
00:00:00
Oh, that's too bad, but at least his foot will be well soon.
00:00:06
He really wants to come into the treehouse, but it's not wheelchair accessible. Have you experienced that?
00:00:10
Yes, a lot of places are not built to accommodate people who are in wheelchairs or have other disabilities.
00:00:15
But today, public places are required by law to be accessible to everyone.
00:00:21
I didn't know that there were laws that require buildings to be accessible to everyone.
00:00:26
What can you do to make buildings accessible to people with disabilities?
00:00:31
Well, a lot of buildings use simple machines, such as a ramp, which is an inclined plane.
00:00:35
Some use elevators, but they are a little more complex.
00:00:40
We need to keep it simple. What is a simple machine?
00:00:44
A simple machine is a device that makes work more convenient by changing the speed, direction, or amount of force.
00:00:47
There are six simple machines, inclined plane, levers, wheel and axle, wedge, pulley, and a screw.
00:00:54
We were thinking that a ramp might be the answer to our problem, but we didn't know that they were simple machines.
00:01:02
Are there any requirements for ramps?
00:01:08
If you want to build Jacob a ramp to get into the treehouse, the ramp will need to be built at a 12 to 1 ratio.
00:01:10
That really helps. It gives us a lot to think about. See you later.
00:01:18
I wonder if there are any other simple machines we need to use to solve our problem.
00:01:22
We need to do more research.
00:01:26
Look, Dr. D is balancing up on that big ball.
00:01:31
I hope he doesn't fall off.
00:01:34
Hi, Dr. D. It looks like you're having a great time.
00:01:36
There's a lot of science here at the Circus Center.
00:01:48
Science? I never knew that there could be science at a circus.
00:01:50
Sure there is. The circus is a great place to get some ideas to help you solve your problem.
00:01:54
We're particularly interested in simple machines.
00:01:59
Great. Right now they're using a teeter board, which is a lever with a fulcrum or rotational point in the middle.
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How does it work?
00:02:09
Let's watch them.
00:02:10
That was pretty neat. I noticed that two men jumped on the board, but only one flew into the air.
00:02:21
Those two men that jumped are called pitchers. The one that flew up in the air is called a flyer.
00:02:27
I should have guessed that one.
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After the pitchers jump, they have a lot of potential energy.
00:02:34
It looks like the flyer went at least twice as high as the pitchers.
00:02:37
Exactly. Two men have the same energy as one man twice as high. The flyer also helps by pushing off the board.
00:02:41
So the lever didn't create any energy.
00:02:49
That's right.
00:02:51
The lever changes the downward motion of the pitchers to the upward motion of the flyers.
00:02:52
Correct. It's not magic. The teeter board just lets them transfer energy from the pitchers to the flyers.
00:02:56
How would you like to experience the flying trapeze?
00:03:02
That would be so cool.
00:03:05
Now what does the flying trapeze have to do with energy?
00:03:07
When you're way up there on the platform waiting, you have a lot of potential energy.
00:03:12
Then when you grab the trapeze and swing down, you build up kinetic energy.
00:03:16
And when you swing back again, you lose kinetic energy and pick up potential energy.
00:03:20
Very good. So energy isn't being transferred like on the teeter board.
00:03:24
It's just changing from potential energy to kinetic energy and then back again.
00:03:28
That's why it's the acrobats on the aerial hoop. These guys are really something.
00:03:33
Someone will have to do a lot of work to lift the hoop and the acrobat together.
00:03:37
It looks really easy to pull them up. What are they using with the rope?
00:03:42
It looks like they're using pulleys attached to the rope.
00:03:46
I think this just might be the thing we need to pull Jacob up into the treehouse.
00:03:48
This is great. We're making some real progress. Thanks, Dr. D.
00:03:52
You're welcome. Let's see it by trapeze training.
00:03:55
- Valoración:
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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:
- 788
- Fecha:
- 28 de mayo de 2007 - 15:32
- Visibilidad:
- Público
- Enlace Relacionado:
- NASAs center for distance learning
- Duración:
- 04′ 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:
- 24.23 MBytes