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Elliptical Orbit Activity - Contenido educativo

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Subido el 28 de mayo de 2007 por EducaMadrid

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NASA Connect Segment involving students participating in an activity to measure and calculate ellipses. The activity explains ellipses and their relation to Earth and Mars.

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Hi, we're from Bridge Street Middle School in Wheeling, West Virginia. 00:00:00
NASA Connect asked us to show you the student activity for this program. 00:00:07
When you think of the Earth or Mars orbiting the planet, 00:00:12
you might think that the orbit is in the shape of a circle. 00:00:15
It's really in the shape of a squashed circle or an ellipse. 00:00:18
The German mathematician and astronomer Johannes Kepler 00:00:21
discovered this fact a long time ago. 00:00:25
In this activity, you'll use measurement and observation 00:00:27
to understand the meaning of the eccentricity of an ellipse. 00:00:30
You'll calculate the distance between Earth and Mars, 00:00:33
determine the length of their orbits, 00:00:36
and learn about their orbital rates as compared to their distances from the sun. 00:00:38
But before we get started, here are the materials you'll need. 00:00:42
A computer with a Spreadsheet program or calculators, 00:00:46
centimeter graph paper, 00:00:50
two push pins for each group, 00:00:52
a string 25 centimeters long for each group, 00:00:54
cardboard, and one metric ruler for each group. 00:00:57
Kepler stated that the orbit of Mars or of any planet 00:01:01
is an ellipse with the sun at one focus. 00:01:04
The other focus is an imaginary point. 00:01:07
There is nothing there. 00:01:09
During part of its orbit around the sun, 00:01:11
Mars is closer to the sun than it is at other times. 00:01:13
This relationship can be seen in solar system data charts 00:01:17
that show the maximum and minimum distances from the sun to each planet. 00:01:20
Astronomers often use the average or mean distance from the sun 00:01:25
instead of the minimum or maximum. 00:01:29
Enter the data from the chart into a Spreadsheet program 00:01:32
or use a calculator, 00:01:35
and for each planet, find the mean distance from the sun. 00:01:37
Now make a sketch of the orbits of the Earth and Mars around the sun. 00:01:41
Another column of data on the planet chart 00:01:45
lists the eccentricity of each planet's orbit. 00:01:48
Eccentricity gives an indication of roundness or squashness of each ellipse. 00:01:51
To understand what this number means, 00:01:56
here is an experiment to do with your team. 00:01:59
On a piece of centimeter graph paper, draw two lines, 00:02:02
one near the middle vertically and one near the middle horizontally. 00:02:06
The lines intersect at the center point. 00:02:10
Measure and cut a piece of string about 25 centimeters long. 00:02:13
Tie a knot near the ends of the string to form a loop. 00:02:17
Place the graph paper on a piece of cardboard, 00:02:21
then place two push pins along the horizontal line, 00:02:24
each one centimeter from the center point. 00:02:28
These pins represent the foci. 00:02:31
At this point, the foci are two centimeters apart. 00:02:34
Loop the string around the push pins, 00:02:38
then use a pencil to keep the string tight and draw an ellipse. 00:02:40
Measure, in centimeters, the length of the ellipse along its major axis. 00:02:44
Record the distance between the two foci and the length of the major axis on a chart. 00:02:49
Then divide the distance between the foci by the length of the major axis 00:02:55
and record the quotient on the chart. 00:03:00
Now repeat these steps using the following distances between foci. 00:03:03
Three centimeters, four centimeters, five centimeters. 00:03:08
Choose your own distance. 00:03:12
After you have recorded the distances between the foci 00:03:14
and the length of the major axis on the data chart, 00:03:17
use a calculator to divide the distance by the major axis length. 00:03:20
The quotient will give you the eccentricity for the ellipses. 00:03:25
Remember, the value of the eccentricity should be a decimal with a value of less than one. 00:03:29
On the chart, make sketches of the ellipses you've created. 00:03:36
Analyze your data, guys. 00:03:40
This would be a great time to stop the video and consider the following questions. 00:03:42
How does the distance between the foci affect the shape of the ellipse? 00:03:46
What is the relationship between the value of the eccentricity 00:03:50
and the roundness or squashedness of the ellipse? 00:03:54
Although the orbits of both Earth and Mars are ellipses, 00:03:58
their orbits are close enough to being circles 00:04:01
that we can estimate the distance from the Earth to Mars. 00:04:03
Let's assume both planets are on the same side of the Sun. 00:04:07
Consider the mean distance from the Sun to each planet as the radius of a circle. 00:04:10
Use the mean distance you calculated from the Sun to Earth and the Sun to Mars 00:04:15
to determine the estimated direct distance between the Earth and Mars. 00:04:20
What if Earth and Mars were on opposite sides of the Sun, like this? 00:04:24
These activities and more are located in the Educator's Lesson Guide, 00:04:29
which can be downloaded from our NASA Connect website. 00:04:33
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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:
365
Fecha:
28 de mayo de 2007 - 16:52
Visibilidad:
Público
Enlace Relacionado:
NASAs center for distance learning
Duración:
04′ 38″
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:
28.14 MBytes

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