09 Astronomy key R - Mrs. Visser's Science Page

[Pages:55]ASTRONOMY

Rotation: - spinning of Earth on its axis - causes daylight and night - 1 day; 23 hours, 56 min, 4 sec - apparent motion of the sun around the Earth - 15? per hour

Evidence of Rotation:

Coriolis effect

Foucault pendulum

- causes deflection of winds and ocean

currents

- deflects to the right in the

Northern Hemisphere

-Circumpolar Stars

- Star trails

1. A Foucault pendulum appears to change its direction of swing due to the (1) tilt of Earth's axis (2) spin of Earth on its axis (3) deflection of Earth's planetary winds (4) movement of Earth in its orbit around the Sun

2. Predictable changes in the direction of swing of a Foucault pendulum provide evidence

that

(1) Earth is tilted on its axis

(3) Earth rotates on its axis

(2) Earth's orbit is slightly elliptical

(4) Earth's magnetic poles reverse over time

3. The apparent shift in the direction of swing of a the motion of a Foucault pendulum

provides evidence of

(1) the Sun's rotation

(3) Earth's rotation

(2) the Sun's revolution

(4) Earth's revolution

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4. The apparent change in direction of a swinging Foucault pendulum is the result of the

(1) rotation of Earth

(3) revolution of Earth

(2) tilt of Earth's axis

(4) shape of Earth's orbit

5. Foucault pendulum is caused by Earth's

(1) revolution

(2) spherical shape

(3) rotation

(4) tilted axis

6. The best evidence that Earth spins on its axis is provided by (1) variations in atmospheric density (2) apparent shifts in the swing of a Foucault pendulum (3) changes in the position of sunspots on the Sun (4) eclipses of the Moon

7. The diagram below represents a Foucault pendulum swinging freely for 8 hours.

The Foucault pendulum appears to gradually change its direction of swing due to Earth's

(1) orbit around the Sun (2) tilted axis (3) curved surface (4) spin on its axis

8. The diagram below shows the equipment used to demonstrate a Foucault pendulum

In the demonstration, a student swings the weight hanging in the pail and then spins the stool. The stool represents

(1) the revolving Earth (2) the rotating Earth (3) the Coriolis effect (4) convection currents

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Revolution: - Earth moving in its orbit around the Sun - takes 1 year, 365.26 days - moves approximately 1? per day - cause the seasons

Evidence of Revolution: - The location of the constellations in relationship to Polaris changes from month to

month.

Locating objects in the sky Celestial sphere The imaginary dome surrounding Earth

Celestial Objects objects on the celestial sphere sun, stars, moon, planets

Altitude

the height above Earth's surface - celestial objects are measured in degrees - ex: the altitude of Polaris equals an observers north latitude

Polaris

Zenith E

N

S

W

Zenith the point located directly overhead of an observer altitude of 90?

Astronomy 251

Azimuth - the angular measurement around Earth's surface

- measured in degrees starting with due North located at 0? Azimuth and moving clockwise around the horizon.

Direct ray of the sun

Also known as the Sun's vertical ray - Occurs when the sun is directly overhead (at the zenith) - NEVER occurs in New York State

Locations on Earth: Label the diagram below using the following locations.

Equator ( 0? ) North Pole (90?N) South Pole (90?S) Tropic Cancer (23 ? ?N) Tropic of Capricorn (23 ? ?S) Axis of rotation Antarctic Circle (66 ? ?S) Arctic Circle (66 ? ?N

North Pole - 90 ?N Arctic Circle - 66 ? ?N

Tropic of Cancer - 23 ? ?N Equator - 0?

Axis of rotation

Tropic of Capricorn 23 ? ?S

252 ESworkbooks?2008cdunbar

Antarctic Circle - 66 ? ?S South Pole - 90 ?S

Base your answers to questions 1 and 2 on the data table below, which shows the azimuths of sunrise and sunset on August 2 observed at four different latitudes. Azimuth is the compass direction measured, in degrees, along the horizon, starting from north.

1. On the outer edge of the azimuth circle below, mark with an X the positions of sunrise and sunset for each latitude shown in the data table. Write the correct letter code beside each X. The positions of sunrise and sunset for 30? N have been plotted and labeled with letters A and B.

2. State the relationship at sunrise

between the latitude and the

azimuth. As the latitude

of the observer increases,

the azimuth decreases.

(or)

As the latitude increases, the sunrise is farther

Azimuth Circle

north of east.

X H X F X D

G X E X C X

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3. Which statement about Polaris is best illustrated by the diagrams shown to the right? (1) Polaris is located in a winter constellation. (2) Polaris is located at the zenith at each location. (3) Polaris' apparent movement through the sky follows a south - to - north orientation. (4) Polaris' altitude is equal to a location's latitude.

4. In which diagram below, is the observer experiencing the greatest intensity of insolation?

5. The diagram below shows an observer on Earth measuring the altitude of Polaris. What is the latitude of this observer?

(1) 43 ?N (2) 43 ?S (3) 47 ?N (4) 47 ?S

254 ESworkbooks?2008cdunbar

? Winter Solstice ? December 21 ? Tropic of Capricorn

(23 ??S) ? Shortest day

(just over 9 hrs)

N

N

? Autumnal equinox ? September 23 ? Equator (0?) ? 12 hours of daylight

N

The diagram below illustrates Earth `s position at the beginning of each season. Draw in the lines to show Earth's movement around the sun throughout the year. Label the seasons, the date it begins, location on Earth where the sun's vertical rays are and amount of daylight (in Northern hemisphere) for each position.

Astronomy 255

? 12 hours of daylight

? Equator (0?)

? Vernal (spring) equinox

? March 21

? Summer Solstice ? June 21 ? Tropic of Cancer

(23 ??N) ? Longest day

(just over 15 hrs)

N

Angle of Insolation / Angle of Incidence

Direct Ray

At what location is the direct ray of the sun? ___E__q_u_a_t_o_r_____________________ What seasons could this be? ______S__p_r_in_g___________ or __________F__a_ll__________

Direct Ray

At what location is the direct ray of the sun? _____T__ro_p__ic__o_f_C_a_p__ri_c_o_r_n_________ What season would this be? ________W__i_n_t_e_r____________________

Direct Ray

At what location is the direct ray of the sun? _____T__ro_p__ic__o_f_C_a_n__c_e_r___________ What season would this be? ________S__u_m__m_e_r_________________ 256 ESworkbooks?2008cdunbar

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