Transcript Sun`s changing vertical ray

Earth’s Seasons
What do we mean when we say:
perpendicular
to orbit plane
23½°
The Earth is Tilted
Most globes show the axis
tilted
But what is the axis tilted
with respect to?
orbit plane
axis
The Reasons for the Seasons
The 23.5 degree tilt of the earth axis
AND
The revolution of Earth around the sun
The number 23.5 shows up often in explaining
the changes with the sun throughout the year.
What is NOT a reason for the
Seasons?
The earth is closer to the sun? NOOOOOO!
Actually, the earth is farthest from the sun in
July (Aphelion)
and
closest to the sun in January (Perihelion)
Seasons for Northern Hemisphere
N
Image not to scale
The tilt of the
earth is 23.5
Altitude = degrees above a horizon
Point directly overhead
Where would Polaris
be located?
If this is in Red Hook,
what is the altitude
of Polaris?
42º
horizon
Season Simulation
Summer Solstice
Winter Solstice
Summer Solstice
Winter Solstice
Summer
Solstice
Concentrated
rays
Winter
Solstice
Rays
Spread
Out
71.5°
Red Hook 42° N
path
48 °
Equinox
path
path
24.5 °
Sun’s Path at Different Seasons in Red Hook
42° N
Facing East in Red Hook
The sun rises here on December 21st
The sun rises here on September 23rd
and March 21st
The sun rises here on June 21st
northeast
east
southeast
The paths of the rising sun in
Red Hook look like this at each season
How many degrees apart is the sun’s rising
position at each season?
Where do you think the sun rose
today? (MAY)
23½
23½
June
northeast
March, Sept.
east
About here
Dec
southeast
Sun’s changing
vertical ray
Red dot shows where
Sun is overhead
Jun 21
Sep. 21
Mar. 21
Dec. 21
Changing Zodiac Constellations
Match the picture with the
season
Date?
September 23
Vertical Ray?
Equator
Sunrise?
Due East
Sunset?
Due West
Duration of
daylight?
12 hours
Shadows at noon?
Average
Autumnal Equinox
Name of orbit
position?
Sun’s Path?
Average
Date?
Dec. 21
Vertical Ray?
23.5 South
Sunrise?
Southeast
Sunset?
Southwest
Duration of
daylight?
8 hours
Autumninal Equinox
Name of orbit
position?
Name of orbit position?
Sun’s Path?
Winter Solstice
Sun’s Path?
Low
Shadows at noon?
LONG
Average
Date?
Mar 21
Vertical Ray?
Equator
Autumninal Equinox
Name of orbit
position?
Sunrise?
Due east
Name of orbit position?
Sun’s Path?
Sunset?
Name of orbital
Winter
Solstice
Due west
Sun’s Path?
position?
Duration of
Low – note
Average
Vernal Equinox long
daylight?
Sun’s Path?
Shadows
shadows at noon?
12 hours
Average
Average
Date?
June 21
Vertical Ray?
23.5 North
Sunrise?
Northeast
Sunset?
Northwest
Duration of
daylight?
16 hours
Orbital position?
Autumninal
Equinox
Summer Solstice
Name of orbit
Shadows at noon?
Sun’s path?
position?
Short
High
Sun’s Path?
Average
At which season is the
Earth very slightly
closer to the sun
Winter (January)
perihelion
On which date is the
Daylight period longer
For the northern hemisphere?
Summer (June)
aphelion
Draw in the path of
The sun on Dec.1st
Label north on the diagram
Label the North Star Polaris
On which date at noon will
the observer cast the
shortest shadow?
Where is the sun’s
Vertical ray striking
On the autumnal
Equinox?
Where is the
sun’s vertical
ray striking on
December 21st ?
equator
23½º N
23½º S
Where is the
sun’s vertical
ray striking on
June 21st ?
On which date is the
Surface temperature most
likely highest?
June 21st
On which date are the sun’s
rays striking most directly?
March 21st
On which date is the heating
from the rays most efficient?
On which date are shadows
at noon the longest?
north
Dec. 21st
east
south