1. Insolation: Incoming Solar Radiation (p.100 in regent review book)
Earth receives almost all of its energy from the sun.

2. How does sunlight (insolation) interact with Earth’s atmosphere?
1) Refraction: Light is bent (water refracts light)
2) Absorption: Light is absorbed by Earth
Nearly all ultraviolet radiation is absorbed in Earth’s upper atmosphere (the stratosphere) by ozone (O3).
The Ozone layer blocks these harmful rays from coming to our planet. These rays are known to cause cancer in humans.

3. How does sunlight (insolation) interact with Earth’s atmosphere
How does sunlight (insolation) interact with Earth’s atmosphere? (continued)
3) Reflection: Whether or not an object reflects or absorbs light has to do with it’s color and texture.
Light colored items reflect more light than dark colored items.
Items smooth in texture will reflect light more readily than items rough in texture.
When clouds are present, solar energy is reflected back into space. Why?

4. How does sunlight (insolation) interact with Earth’s atmosphere
How does sunlight (insolation) interact with Earth’s atmosphere?(part 3)
4) Scattering of light: Aerosols (you know them better as condensation nuclei) will cause light to be reflected and scattered.
Some examples of aerosols (condensation nuclei) are pollutants from cars, homes, factories, fire, dust, cloud droplets or ice crystals.

5. Factors affecting Insolation
Angle of Incidence: One important factor that affects the absorption of solar energy is the angle at which the insolation strikes Earth’s surface.
Tropical regions (near the equator) receive more sunlight because of the sun’s high altitude in the sky than polar areas.

6. Factors affecting Insolation
2) Surface Characteristics
3) Change of State (transpiration)
When energy from insolation is involved in the change of state and transpiration it is not available to raise the temperature of Earth’s surface.

7. The Greenhouse Effect

8. The Greenhouse Effect
The Greenhouse Effect acts as a thermal blanket, reducing the amount of energy loss to space and raising the temperature of Earth’s surface.
The greenhouse effect is a result of the conversion of shortwave energy to longer wave radiation which is prevented from escaping Earth’s atmosphere. (see the bottom of p.14 in your reference table.)

9. Seasons (p. 116 in regent review book)
Our planet takes just over 365 days to orbit the Sun – the basis of our calendar year
The Earth's axis is tilted at an angle of 23.5 degrees

10. Seasons (continued)
This means that different parts of the globe receive varying amounts of sunlight during the year, creating the seasons
Zenith: 90 degree angle
This is a term used regularly to state where the sun is at a given season.

11. Diagram of the Seasons

12. Summer
The day the north pole is nearest the Sun is called the 'summer solstice'. Looking from Earth, the Sun reaches its highest point in the sky all year. This means it takes the most amount of time to cross the sky. So this is the longest day of the year and happens around 21 June. Astronomers call this the start of summer and after this date, days start getting shorter.

13. Summer in NY
In the summer season, the sun is at zenith with the Tropic of Cancer. The Tropic of Cancer is at a latitude of 23.5 degrees north.
New York (41-45 degrees north latitude) has 15 hours of daylight at the summer solstice because the sun rises well into the north east and sets in the northwest. This is when the noon sun is at a 71.5 degree angle. Insolation is the strongest at this time of year. The sun is never at zenith (90 degrees) with NY.

14. Fall (Autumn)
As we continue our journey around the Sun, the north pole moves away from the Sun. The Sun rises lower in the sky so the days continue getting shorter. When the Sun is at its mid-point in the sky, we reach the 'autumn equinox', around 22 September. Day and night are both 12 hours long and its the beginning of autumn

15. Fall and Spring in NY
During both the fall and spring equinox, the sun is at zenith with the equator.
Remember, the latitude of NYS is degrees North. The sun is more south of us than it is in the summer.
For NY, at 12 noon, the sun reaches its highest altitude, 48 degrees.
Quick Reminder: The sun rises on the East and sets on the West.

16. Winter
The day when the north pole is furthest from the Sun is called the 'winter solstice'. The Sun crosses the sky at its lowest point all year. Therefore it crosses the sky in the quickest time so this is the shortest day of the year. Winter solstice happens around 22 December and marks the start of winter. From then on, the days start getting longer.

17. Winter in NY
The Sun is at zenith with the Tropic of Capricorn, December 21.
Because of this the sun is never very high in the sky even at 12 noon. This is why solar energy is the weakest at this time of year.
At 12 noon the highest angle the sun reaches for NY is 24.5 degrees. The sun rises around 7:30am and sets at 4:30pm.

18. Spring
The Earth continues on its path, and our north pole starts moving towards the Sun again. The Sun moves upwards in our skies and the days continue getting longer. Again, we reach a midpoint when day and night are both 12 hours long. This is called the 'vernal (or spring) equinox' and happens around 21 March.

19. Latitudes of Earth

20. Some “Season” Facts
Seasons across the world The further north or south you live in the world, the more pronounced the seasons are. For example, in the far north, Alaska has sunshine 24 hours a day during their summertime.
On the equator If you live near the equator, the Sun doesn't shift up and down in the sky as much. This means that the length of day temperature doesn't vary as much. So countries near the equator only have two seasons - rainy and dry.

21. Why does the Earth tilt at 23.5 degrees?
No one knows why the Earth's axis is tilted by 23.5 degrees. Some astronomers think that about 5 billion years ago, when the Earth was still very young, it was struck by a Mars-sized planet. This colossal impact could have tipped our planet over. Whatever the reason, it's a good thing - if the Earth did not tilt, countries near the poles would be cold and dark all year round. If it tilted too much, the seasons would be very extreme – like on the planet Uranus. Here the winter lasts for 42 years in total darkness!

22. What is really moving, the Earth or the Sun?
At one time, it was believed that we had a Geocentric Solar System.
It was developed by Aristotle in the 4th century B.C.
The Geocentric model shows a stationary Earth as the center with the Sun, Moon, planets, and stars revolving at different speeds in circular orbits.

23. The Geocentric Model

24. The Heliocentric Model
Since the geocentric model did not explain the complex motions of planets, another model was proposed by Copernicus during the 16th century.
The Heliocentric (Sun-centered) Model states that the Sun, not Earth, is the stationary center of our solar system. This is the acceptable model of our solar system today.

25. The Geo/Heliocentric Debate
Aristotle & Ptolemy thought that all celestial objects — including the planets, Sun, Moon, and stars — orbited Earth. Earth, in the center of the universe, did not move at all.
Copernicus thought that the planets orbited the Sun, and that the Moon orbited Earth. The Sun, in the center of the universe, did not move, nor did the stars.

26. The Heliocentric Model Today’s accepted model!!!!!!