1. 10/6/2017
Friday

2. Science Log Semester 1 week 6
Friday, October 6:
Do you think the longest day of the year is the same all over the Earth? Why or why not?

3. 8. graphs
What does the graph reveal about the amount of daylight in the Northern Hemisphere over 1 year?
Daylight gets longer from January to June, and shorter from June to December.
When do people in the Northern Hemisphere experience the longest daylight?
June
When do people experience the shortest daylight?
December
When do people experience about 12 hours of daylight?
March and September
How many hours of daylight do people have on their longest and shortest day?
In what season do people have their longest and shortest days?
Longest in summer, shortest in winter.

4. 9. Day-Length questions
Look at the “Worldwide Sunrise/Sunset Data” in the images and Data section of the book.
What do you notice
Summer, locations farthest north received the most sunlight hours and that in the winter, it was the opposite.

5. 9. Day-Length questions Discuss in your groups
When one location on Earth has 14 hours of daylight, is the rest of the world having 14 hours of daylight as well? Explain.
Is the longest day of the year the same length all over the world? Explain.
Is the longest day of the year the same date all over the world? Explain.
Are the days with the longest daylight always in the summer? Are the days with the shortest daylight always in the winter? Explain.

6. 9. Day-Length questions
When one location on Earth has 14 hours of daylight, is the rest of the world having 14 hours of daylight as well? Explain.
No, daylight length varies around the world, depending on latitude.
Is the longest day of the year the same length all over the world? Explain.
No, it depends on the latitude of the observer.
Is the longest day of the year the same date all over the world? Explain.
No, the longest day in the Northern Hemisphere is the summer solstice on June 21, but the longest day in the Southern Hemisphere is their summer solstice on December 21.
Are the days with the longest daylight always in the summer? Are the days with the shortest daylight always in the winter? Explain.
Yes, although summer occurs in different months north and south of the equator.

7. 9. Day-Length questions
Answer your questions, put it in on page 47

8. 12. Day Length
There are more hours of daylight in summer than in winter.
What ideas do you have to explain why daylight hours change over 1 year?
Discuss in your groups, be ready to answer

9. 13. Large globe
The North star represents the actual location of the North Star as viewed from Earth.
Earths North pole points toward the North Celestial Pole, which is near the North Star.
Again, the light is the sun
How should the globe move, and be tilted?
What direction?
Yes, counterclockwise revolution around the lamp (Sun), degrees toward the North Star, rotation on the Earths axis is also counterclockwise.

10. 14. Hours of daylight
We know that it takes 1 year—12 months—for Earth to make one trip around the Sun, I’m going to place Earth in four different locations around the sun, and let’s observe how long the day is in each location.
Try to find out where Earth is in its orbit when days are longest during the year.

11. Position 1

12. Positon 2

13. Position 3

14. Position 4

15. 15. Globe observations
Recall the duration of light at each position of the globe.
Where was the globe positioned when our town experienced the longest daylight?
The fourth position
Which way was Earth’s axis titled?
The North Pole was tilted toward the Sun.
Where was the globe positioned when our town experienced the shortest daylight?
The second position

16. 15. Globe observations Which way was Earth’s axis titled?
The North Pole was tilted away from the sun.
The four positions of the globe represent the four seasons. Which position was summer?
The fourth position
Which position represented winter?
The second position.
Which position represented spring?
The third position
Which position represented fall?
The first one

17. 16. Four seasons
The amount of sunshine falling on our town changes throughout the year.
The time when daylight is longest we call summer.
The time when daylight is shortest we call winter.
Halfway between summer and winter, when daylight hours are about equal to nighttime hours, we call spring and fall.
Summer, fall, winter, and spring are the four seasons, and the length of daylight in each season is predictable.

18. 17. Equinox
There are 2 days during the year that day and night hours are equal.
These days are called equinoxes.
Equinox comes from Latin, meaning equal night.
One equinox, the spring, or vernal, equinox, occurs around March 21, and it makes the first day of spring.
The other equinox is the autumnal equinox, and it marks the first day of fall, or autumn.
When do you think the autumnal equinox occurs?
Around September 22 or 23

19. 18. Solstice
The day of the year with the longest daylight is called the summer solstice.
The summer solstice occurs on about June 21 and marks the first day of summer.
The day of the year with the shortest daylight is called winter solstice.
When do you think the winter solstice occurs?
Around December 21

20. Vocab page 39, put in index
Equinox: a day of the year when the Sun’s rays shine straight down on the equator.
Solstice: a day of the year when Earth’s North Pole is leaning either toward the Sun or away from the Sun

21. 20. Seasons variables
Think about the long daylight during the summer and the short daylight during the winter.
What variables affect daylight length?
Why are there more hours of daylight in summer and fewer in winter?
Discuss in your groups to identify the important factors in determining day length.

22. The tilt of Earth’s axis is always 23.5 degrees.
20. Seasons variables
The tilt of Earth’s axis is always degrees.
The axis tilt points in the same direction, toward Polaris, the North Star.
The position of Earth changes as it orbits around the Sun.

23. 21. Answer focus question page 46
Why are there more hours of sunlight in the summer?