Good Morning!!! TEST DAY

Good Morning..Can you answer? What evidence is there for Earth’s revolution around the Sun? Describe the shape of Earth’s orbit and explain how Earth’s position relative to the Sun changes as Earth revolves. Name the solstices and equinoxes and dates on which they occur. How would the solstices and equinoxes change if the Earth’s orbit were circular instead of elliptical? Explain how a circular orbit would affect seasonal changes.

Good Morning… Can you….. Explain the nebular hypothesis Describe the size and shape of Earth Describe the compositional and structural layers of Earth’s interior. Identify the possible source of Earth’s magnetic field. Summarize Newton’s law of gravitation. List and describe the four spheres that make up our Earth. List and explain the evidence for the rotation and revolution of Earth?

Earth’s Rotation & Revolution Part II

Effects of Revolution and Tilt Effects of Earth’s revolution include the season and variation in the length of days and nights.

Earth’s tilt also has a profound effect on the seasons, THE DISTANCE FROM THE SUN IS NOT THE REASON WE HAVE SEASONS.

At any given time one hemisphere is pointed away from the Sun, while the other is pointed toward the Sun

How would changing the degree of the tilt effect life on the Earth? Question How would changing the degree of the tilt effect life on the Earth?

Equinox There are two days each year, midway between the solstices, when neither hemisphere tilts toward the Sun.

On these days, daytime and nighttime are nearly equal (not exactly, this varies with your location)

Vernal equinox-which occurs on or around March 21st Autumnal equinox- which occurs on or around September 22

The Sun is overhead the equator at noon on these dates

On March 21st the sun rises above the horizon at the North Pole for the first time in six months, and remains in the sky for the next 6 months; this starts 6 months of darkness for the South Pole

Summer Solstice The first day of summer in the Northern Hemisphere Occurs on or about June 21st

Has the longest daylight period, because the sun’s path across the sky is longer and higher than at any other time of the year. At this point the daily increase of the Sun rising in the sky stops.

This is when the Northern Hemisphere is at its maximum tilt toward the Sun. This is when the Southern Hemisphere is at its maximum tilt away from the Sun.

The Sun is directly overhead at the latitude 23 The Sun is directly overhead at the latitude 23.5°N, also known as the Tropic of Cancer

On this day everything above 66 On this day everything above 66.5° N latitude (The Arctic Circle) receives 24 hours of daylight, and everything south of 66.5°S (the Antarctic Circle) receives 24 hours of darkness

Winter Solstice The first day of winter for the Northern Hemisphere Occurs on or about December 21st

Has the shortest daylight period, because the sun’s path across the sky is shorter and lower than at any other time of the year. At this point the daily decrease of the Sun rising in the sky stops.

This is when the Northern Hemisphere is at its maximum tilt away from the Sun. This is when the Southern Hemisphere is at its maximum tilt toward the Sun.

The Sun is directly overhead at the latitude 23 The Sun is directly overhead at the latitude 23.5°S, also known as the Tropic of Capricorn

On this day everything above 66 On this day everything above 66.5° N latitude (The Arctic Circle) receives 24 hours of darkness, and everything south of 66.5°S (the Antarctic Circle) receives 24 hours of daylight

Effects of Rotation Foucault’s Pendulum

Quick Video Foucault’s Pendulum

Coriolis effect-ocean and wind currents do not move in a straight path, they are deflected to the right in the Northern Hemisphere

Coriolis

The Daily Change from Day to Night The Sun rises in the east and sets in the west only ½ the Earth receives sunlight at any given time, if the Earth didn’t rotate the side facing the Sun would receive constant daylight

Measuring Time Each day the Sun rises on the eastern horizon, seems to move in an arc across the sky, and sets below the western horizon. Solar noon occurs when the Sun is at the highest position on this arc

Because of Earth’s rotation solar noon does not occur at the same time everywhere It moves westward at a rate of about 15° each hour, or 1° every four minutes

Example: New York City, located at longitude 74° W, and Philadelphia which is near 75° longitude. Because of the 1° difference in longitude, solar noon occurs in New York City about four minutes before it occurs in Philadelphia

Standard Time Zones There are 24 worldwide standard time zones, each are 15° longitude wide The basis for the time zones is the rate at which the Sun appears to move across the sky

Each time zone line is called a time meridian, all areas within a time zone keep the same clock time; clock time is the average solar time at that zone’s time meridian

The starting point for the standard time zones is an arbitrary longitude line called the prime meridian, which passes through Greenwich, England.

The Prime Meridian in Greenwich, England National Maritime Museum

Travelers moving westward from Greenwich move their clocks back to earlier times and vice versa Time zone lines are seldom perfectly straight lines. What could be the reason for this?

International Date Line Travelers going completely around the world gain or lose time at each time zone until they have gained or lost an entire day

An imaginary line called the International Date Line represents the longitude at which the date changes.

It is goes through the Pacific Ocean, if you are traveling westward the date is one day later and vice versa For much of each day, the U.S. is one day behind Asia

For the rest of class Put your Unit 4 packet together and STAPLE it Make 3-4 test Questions PER PAGE