Motions of the Planets: Rotation, Revolution, Gravity, Inertia

BY: BRIANNA SHIELDS

DO NOW

• 1. Which planet exhibits retrograde rotation?

• 2. Which type of “space debris” consists of a ball of ice, snow and dust?

• 3. Which planet has soil containing iron oxide, a component of rust?

GOAL

• To be able to describe the bodies found in our solar system and the way in which they move

Gravity and Inertia

• Gravity

• Holds planets in orbit around sun, prevents them from flying off

Gravity and Inertia

• Inertia • Allows them to continue in forward motion

• An object in motion stays in motion, an object at rest stays at rest, unless acted on by a force

Gravity and Inertia

• WEBSITES • Exploring Gravity• Keeping Satellites in Orbit• Science Monster Gravity and

Inertia Game

Rotation versus Revolution

• ROTATION– Spinning on its

axis– Causes day and

night– 24 hours– Side facing sun

= day

• REVOLUTION– Going around

another object– Causes seasons– 365 1/4 days– Hemisphere tilted

toward sun has summer

What causes day & night on Earth?

QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.

Rotation

Rotation

What causes seasons on Earth?

QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.

Seasons

• Summer Solstice

• Summer= June 21 (longest day of year)

• N. hemisphere tilted farthest toward sun

• N. hemi gets more direct sunlight causing intense warming of earth’s surface

Seasons

• Winter Solstice

• Winter= Dec 21 (shortest day of year)

• N. hemisphere tilted farthest away sun

• N. hemi gets more spreading of sunlight causing weak rays to hit earth’s surface

Seasons

• Autumnal Equinox

• Fall= Sept 21• Earth’s axis is not tilted

toward or away from sun• After summer, before winter

Seasons

• Vernal Equinox

• Spring= March 21• Earth’s axis is not tilted

toward or away from sun• After winter, before summer

Seasons

• WEBSITES • How does the earth’s tilt cause seasons?

Seasons

• WEBSITES • Seasons• Observing Motions in the Sky

1• Observing Motions in the Sky

2• Orbit Simulator• Current Day and Night on

Earth

Sketching the Rotation of the Earth

• Create a sketch of the Earth in your notebook, but make sure you do the following:

• 1. Draw the sun in the center• 2. Draw four Earths in four

positions around the sun (summer, winter, spring and fall)

• 3. Make sure the Earth is tilted correctly for each season

• 4. Label each Earth with the season and write an explanation as to the cause of each of the seasons

Assessment: Poster

• Pick your favorite planet and create a poster with the following requirements:

• Explain each of the following terms by drawing a picture. Accompany each term with a brief explanation.– Gravity– Inertia– Rotation– Revolution

• Now color the planet and record the following for your planet:– Amount of gravity– Period of rotation– Period of revolution

Assessment: Questions

• Answer each of the following questions in your notebook:

• 1. How much of the Earth is facing the sun at any given time?

• 2. How do you know what side of the Earth is experiencing day?

• 3. When does summer occur in the southern hemisphere (what month). What is going on with the Earth to cause this?

• 4. What is the name of the Earth’s motion that describes why we have night and day?

• 5. Explain the positioning of the Earth during the winter solstice

Assessment: Questions

• Answer each of the following questions in your notebook:

• 6. What occurs during both the autumnal and vernal equinoxes?

• 7. Why does the Northern Hemisphere experience winter during November - February? Why is it colder during these months?

• 8. How long does day last on June 21 in the arctic circle?

• 9. Where on Earth does the length of day and night never change?