Gravity Gets Me down, Man
Top Ten Reasons Why We Know the Earth Is Round
Happy Feet Clip
Penguin Falling
Schoolhouse Rock: Victim of Gravity
Maps with South Up
Extension Lessons: Gravity on the moon and in space
Happy Feet Clip
Penguin Falling
Schoolhouse Rock: Victim of Gravity
Maps with South Up
Extension Lessons: Gravity on the moon and in space
05 Gravity Pulls Me Down, Man
5-PS2-1. Support an argument that the gravitational force exerted by Earth on objects is directed down.
The gravitational force of Earth acting on an object near Earth’s surface pulls that object toward the planet’s center.
- The Earth is spherical
- True down is toward the Earth’s center.
- Gravity pulls down on objects near the Earth’s surface no matter where they are on the Earth.
- Objects fall down no matter where you are on the Earth.
Gravity on Earth
Seek: Have you ever thought about gravity? What is it? What does it do?
Try: How do we know that the earth is round? https://www.youtube.com/watch?v=o_W280R_Jt8
Show globe: if gravity makes you fall down, what happens to people who live here? Show Happy Feet clip: https://www.youtube.com/watch?v=C1vgO8fba1U and clip of penguin falling: https://www.youtube.com/watch?v=nFAK8Vj62WM Show alternate maps: http://en.wikipedia.org/wiki/South-up_map_orientation.
Expand: Schoolhouse Rock: Victim of Gravity; notes and draw Earth with arrows pointing in from all over to show down is toward center
Make Connections: Reflect in words and pictures: Support an argument that the gravitational force exerted by Earth on objects is directed down.
ASSESSMENT: Look for students who cannot give evidence and explain that gravity pulls down everywhere on Earth.
“Students describe* a chain of reasoning that includes:
i. If Earth is spherical, and all observers see objects near them falling directly “down” to the Earth’s surface, then all observers would agree that objects fall toward the Earth’s center.
ii. Since an object that is initially stationary when held moves downward when it is released, there must be a force (gravity) acting on the object that pulls the object toward the center of Earth. “
Extend: http://shows.howstuffworks.com/stuff-to-blow-your-mind/51310-stuff-to-blow-your-kids-mind-gravity-video.htm
http://blogs.discovermagazine.com/d-brief/2014/11/06/watch-feather-bowling-ball-fall-speed/#.VRFrJ2TF9XY (1:10)
Bill Nye on Gravity
Extension Lessons:
Extension: Gravity on the Moon
(adapted from Weight, Mass, and Gravity on BetterLesson.com: http://betterlesson.com/lesson/626414/weight-mass-gravity)
Seek: Have video of first moon landing playing as students walk into classroom. (Downloadable from NASA: http://video.nationalgeographic.com/video/101-videos/moon-101-sci)
What do you know about gravity in space? What if we were on the moon? Show Lunar Olympics video. https://www.youtube.com/watch?v=16D0hmLt-S0
Try: Can we jump that high?
Set up three meter sticks against one of the window walls (folded against a surface for safety). Mark 4 feet to show height of moon jump. Clarify that that would be where his feet touched. Have student hold dry erase marker and mark reach. Then have student jump and mark jump height with dry erase marker. Measure and calculate the difference between reach height and jump height to calculate how high a person can jump on either.
Discuss weight of backpack, mentioned in video. Point out that backpack weighs 180 pounds. Give students 20 pound backpack and have them figure out how much more the spacesuit backpack weighs.
Expand: Why can astronauts jump so much higher on the moon?
http://video.nationalgeographic.com/video/101-videos/moon-101-sci
The moon is smaller than the Earth, so it has less gravity. Emphasize that gravity still pulls down, toward the center, of the moon. (Gravity on moon is about ⅙ of that on Earth.)
http://teacher.scholastic.com/activities/explorations/space/level1/MoonOlympics.htm
What about in space? https://www.youtube.com/watch?v=coX1u2_KBsQ
Make Connections: Have students reflect, in words and pictures, about what they learned.
Extend:
Calculate height of high jump on moon: https://www.youtube.com/watch?v=6CkAfx1E58M
Your weight on the moon (clarify what weight is!): http://www.moonconnection.com/moon_gravity.phtml
http://spaceplace.nasa.gov/what-is-gravity/en/
Extension: What About Gravity on Mars?
(adapted from Red Planet: Read, Write, Explore! http://lasp.colorado.edu/home/maven/education-outreach/for-educators/red-planet/) Note: This is similar to Montessori lesson Trip to the Moon.
Before: Fill two identical containers so that one weights ⅓ of the other. The Earth container might weigh 1.2 kg, while the Mars container weighs 400g. Seal the containers and make sure students cannot see into them.
Seek: If we were to go to Mars, what would the gravity be like there?
Try: Have students imagine they are going on a trip to Mars. Briefly discuss what they might bring, and then produce the Earth container. Pass around container.
Remind students that they cannot feel the force of gravity in space, so while they are travelling, the package would have no weight.
Have students imagine they have arrived on Mars, and have them pass around the Mars container.
Expand: Discuss what students noticed about the weight of the container. From Red Planet: Read, Write, Explore!:
The gravity of a planet is determined by the mass of the planet. Mass is a fixed quantity, but weight is not. Weight is a value defined by how much the planet is pulling you down! If you traveled to Mars, you would you would weigh less because Mars is a less massive planet than Earth and is not pulling as much on you. The gravity on Mars is roughly 1/3 the gravity on Earth. That means objects would weigh about 1/3 of their Earth weight if you brought them to Mars.
Example discussion questions:
What did you notice about the weight of the container? A. The weight of the container on Mars is less heavy.
Would your body feel heavier or lighter on Mars? Why? A. There is less gravity on Mars, so you would feel lighter.
Can you think of things you could do on Mars that you could not do on Earth? A. You could jump about three times higher). You could move objects (like big rocks) that would be too heavy to lift on Earth. You could throw things farther than you could on Earth.
Would you float away on Mars? A. No, there is still plenty of gravity to hold you down.
Make Connections: What might this imply for living on Mars? Have students reflect.
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