Transcript The Sun

The Sun’s Size, Heat, and
Structure
The Sun’s Size, Heat, and
Structure
Drawing the Sun’s Layers to Scale
Layer
Radius in km / Scaling Factor = Radius of
Each Layer in
cm
Convective
Zone
495,000/ 69,500 km =
695,000 km
1 cm
Radiative
Zone
190,000/ 69,500 km =
495,000 km
1 cm
Core
0-190,000 km / 69,500 km =
1 cm
=
=
=
Characteristics
(List these on
drawing)
The Solar Wind is the cause of
geomagnetic storms and the
Aurora Borealis (Northern
Lights)
The Aurora Borealis (Northern
Lights)
The Sun is powered by
nuclear fusion.
The Sun Burns Hydrogen and
converts it to Helium +
Energy
Plasma is a fourth state of
matter. Charged nuclei of
particles fuse together.
Plasma is a fourth state of
matter. Charged nuclei of
particles fuse together.
Normal Hydrogen Atom with
proton (+) and electron (-)
In Plasma, electrons are
stripped away from the
nucleus.
“Since nuclei are positively charged, they
will repel other nuclei. Only tremendous
heat and pressure will cause the nuclei
to fuse. Such temperatures and
pressures occur naturally in stars where
they are ultimately caused by
gravitational forces.”
Summary of Fusion Reactions
Solar Energy is derived from the
conversion of mass to Energy.
Albert Einstein is famous for his
equation E=mc2.
Assignment
Your job is to draw the model of
the sun on butcher paper using
colored pens/pencils. You should
describe all the layers and
temperatures. You also need to
discuss how the sun makes
energy (fusion), how/when
sunspots form, and the solar
wind and what it does to Earth.
Historical Observations of
the Solar System
“The idea that the Earth was
stationary and the sun
moved across the sky was
the idea that prevailed for
over two thousand years.”
What is a geocentric model?
It’s the idea that Earth was
at the center of the
Universe. The stars were
thought to move around
the Earth.
The same constellations
were noticed to be visible
at the same time each
year.
A few points of light seemed
to move however, or
wander. What were these
things?
These were the planets!
Planet means wanderer.
The most perplexing of all was
retrograde motion of Mars,
the observation that it
stopped moving eastward and
moved westward for a few
weeks.
Retrograde Motion
Ptolemy, a Greek Astronomer in
the 2nd Century A.D., believed
that the planets orbited Earth
in Epicyles. This idea was
accepted until the 16th
Century.
Copernicus (1473-1543),
proposed the Heliocentric
Model, the idea that the
sun is the center of the
solar system and the
planets revolve around the
sun.
We use Copernicus’s model
to this day.
Enter Tycho Brahe in the
th
16 Century. This Danish
astronomer made very
accurate observations of
the movement of planets
and their moons.
Tycho Brahe in his
observatory, Uraniborg.
Brahe died in 1601. His work
was extended by his
assistant, Johannes Kepler.
Kepler went on to make an
unexpected discovery and
formed Kepler’s Laws!
What was this?
The planets orbit in ellipses
with the sun at one foci.
This is Kepler’s First Law.
Earth
Sun
Focus
Focus
The planets sweep out equal
areas in equal times. This
is Kepler’s Second Law.
Earth
1
Sun
Focus
Focus
Kepler’s Third Law says that
the Period squared equals
the average Distance
2
3
Cubed. P = D
Earth
1
Sun
Focus
Focus
Isaac Newton and His
Physical Laws
Newton invented calculus,
studied the composition of
light, and established classical
physics.
Newton’s First Law
An object in motion will stay
in motion unless acted upon
by an outside force. An object
at rest will stay at rest unless
acted upon by an outside
force. This is the foundation
of space travel.
Newton’s Second Law
The Force on an object
equals it’s mass X
acceleration (gravity).
Force = mass x acceleration
F = ma
Newton’s Third Law
For every force, there is an
equal and opposite force. The
basis behind rocket
propulsion.
Force
a on b
= Force
b on a
Newton’s Law of Gravitation
The gravitational force on
two bodies (planet and
sun) is proportional to
mass and inversely
proportional to the square
of distance.
2
Forcegravity = Gm1m2/d
Earth’s Rotation and
Revolution
Rotation is the spinning of
Earth around its axis. It’s
takes 24 hours for the
earth to rotate on its axis.
Evidence for Earth’s Rotation is given by a
Foucault Pendulum. YouTube video of
the Foucault Pendulum at the Griffith
Observatory!
We also know that the Earth rotates
from west to east because the sun
rises in the east, moves through the
southern sky (in the northern
hemisphere), and sets every day in
the west.
Time Zones are needed to account for the fact
that the Sun is not in the same position
everywhere at the same time.
Revolution is the movement
of Earth around the Sun.
It takes 365 ¼ days to
revolve around the Sun.
Evidence for revolution is
indicated by the changing
view of the stars
throughout the year. The
Earth’s seasons also give
evidence of revolution.
Star Parallax, an apparent
shift in star position, is
another piece of evidence.
The Earth’s seasons also
give evidence of
revolution.
Earth’s Axis is tilted at 23.5°
from the vertical. This
gives way to the seasons.
Solstice means “sun still.”
Equinox means “equal
night.”
Autumnal
Equinox
Winter Solstice
September 22nd
December 21st
Summer Solstice
June 21st
Vernal Equinox
March 21st
Table of Seasons
Season
Summer
Solstice
(First Day
of
Summer:
around
6/21)
Autumnal
Equinox
(First Day
of Fall:
around
9/22
Winter
Solstice
(First Day
of Winter:
around
12/21)
Vernal
Equinox
(First Day
of Spring:
around
3/21)
Day
Around 14 12 hours
Length at hours
LCHS
Around 10 12 hours
hours
Sun
23.5° N at 0° at
Directly
Tropic of Equator
overhead: Cancer
23.5° S at 0° at
Tropic of Equator
Capricorn
Here are two animations for the
reasons for our seasons.
Animation 1 and Animation 2
What kinds of radiation does the
sun emit?
According to Wien’s Law, 2,900,000/Temp in Kelvin, the peak
emission of the sun is 2,900,000/6000K. This is equal to 483 nm,
the color of blue-green light. This is why our eyes have evolved to
detect the visible spectrum.
The electromagnetic spectrum.
According to Wien’s Law, 2,900,000/Temp in Kelvin, the peak
emission of the sun is 2,900,000/6000K. This is equal to 483 nm,
the color of blue-green light. This is why our eyes have evolved to
detect the visible spectrum.
What kinds of radiation does the
sun emit?
According to Wien’s Law, 2,900,000/Temp in Kelvin, the peak
emission of the sun is 2,900,000/6000K. This is equal to 483 nm,
the color of blue-green light. This is why our eyes have evolved to
detect the visible spectrum.
What kinds of radiation does the
sun emit?
UVA and UVB light can get through to the Earth’s surface. Lucky
for us, UVC light is blocked.
Consequences of Not using
sunscreen
Sunburn
Skin Cancer
Melanoma
Cataracts
Sunscreen Lab: Chemistry of
Sunscreen
Active
Ingredients: Contains: Octinoxate 2%
(Sunscreen), Padimate O 1.4%
(Sunscreen)
Inactive Ingredients: Mineral Oil, Aloe
Barbadensis Leaf Extract, Cocos Nucifera
Oil (Coconut), Theobroma Cacao Seed
Butter (Cocoa), Musa Sapientum Fruit
Extract (Banana), Tocopherol Acetate
(Vitamin E Acetate), Retinyl Palmitate
(Vitamin A), Daucus Carota Sativa Root
Extract (Carrot), Phenoxyethanol,
Methylparaben, Isopropylparaben,
Isobutylparaben, Butylparaben, Fragrance
Sunscreen Lab
Active Ingredients: Padimate O 5.4%,
Oxybenzone 1.2%
Inactive Ingredients: Acrylates/C10-30
Alkyl Acrylate Crosspolymer, Aloe
Barbadensis (Leaf Juice), Cetyl Alcohol,
Cocos Nucifera (Coconut Oil), Fragrance,
Glycerl Stearate, Hydrolyzed Collagen,
Imidazolidinyl Urea, Isocetyl Alcohol,
Methylparaben, Mineral Oil, Mink Oil,
Polyethylene, Polyglyceryl 3 Dioleate,
Propylparaben, Quaternium 15, Sorbitol,
Stearic Acid, Theobroma Cacao Cocoa
Seed Butter, Tocopheryl Acetate,
Triethanolamine, Water
Sunscreen Lab
Did you notice the inactive mink oil ingredient? This
comes from the thick fatty tissue just under the skin of
the mink. It is used in cosmetics and is used to coat shoe
and baseball glove leather.
Sunscreen Lab
Active Ingredients: Padimate O 5.0%
(Sunscreen), Oxybenzone 3%
(Sunscreen), Octinoxate 2% (Sunscreen)
Inactive Ingredients: Acrylates/C10-30
Alkyl Acrylate Crosspolymer, Aloe
Barbadensis (Leaf Juice), Cetyl Alcohol,
Cocos Nucifera Oil (Coconut), Fragrance,
Glyceryl Stearate SE, Hydrolyzed Collagen,
Imidazolidinyl Urea, Methylparaben,
Mineral Oil, Mink Oil, Polyethylene,
Polyglyceryl 3 Oleate, Propylparaben,
Quaternium 15, Sorbitol, Stearic Acid,
Theobroma Cacao Seed Butter (Cocoa),
Tocopherol (Vitamin E), Triethanolamine,
Water
Sunscreen Lab
Active Ingredients: Octinoxate (7.5% Sunscreen), Oxybenzone (5.25% Sunscreen), Octisalate (4.75% Sunscreen), Titanium Dioxide (1.2% Sunscreen)
Inactive Ingredients: Aloe Barbadensis
(Leaf Juice), Alumina, Aluminum Stearate,
C12-15 Alkyl Benzoate, Ceteareth 20,
DMDM Hydantoin, Glyceryl Stearate,
Hydrolized Collagen,
Hydroxyethylcellulose, Imidazolidinyl Urea,
Iodopropynyl Butylcarbamate, Isopropyl
Myristate, Magnesium Aluminum Silicate,
Methyl Acetyl Ricinoleate, Octadecene/MA
Copolymer, PEG 40 Castor Oil, PEG 7
Glyceryl Cocoate, Polyethylene,
Polyhydroxystearic Acid, Quaternium 15,
Silica, Stearic Acid, Stearyl Alcohol,
Tocopheral (Vitamin E), Triethanolamine,
Trisodium EDTA, Water
Sunscreen Lab
Active Ingredients: Avobenzone (1.5%)
(Sunscreen), Homosalate (15%)
(Sunscreen), Octisalate (5%) (Sunscreen),
Octocrylene (1.25%) (Sunscreen),
Oxybenzone (6%) (Sunscreen)
Inactive Ingredients: Water,
Hydrogenated Dimer
Dilinoley/Dimethylcarbonate Copolymer,
Stearyl Alcohol, Glycerin, Caprylyl Glycol,
Aloe Barbadensis (Aloe Vera) Leaf Juice,
Tocopherol Acetate (Vitamin E), Retinyl
Palmitate (Vitamin A), Tocopherol, Sodium
Lauroyl Sarcosinate, Behenyl Alcohol,
Glyceryl Stearate, Glyceryl Stearate
Citrate, Disodium Ethylene Dicocamide
Peg 15 Disulfate, Cetyl Alcohol, Dimethyl
Capramide, Cetearyl Alcohol, Sodium
Lauroyl Lactylate, Lecithin, Carbomer,
Xantham Gum, Methyldibromo
Glutaronitrile, Methylchlorisothiazolinone,
Methylisothiazolinone, Phenoxyethanol,
Disodium EDTA, BHT
Sunscreen Lab
Active Ingredients: Octinoxate (7.5% Sunscreen), Oxybenzone (6.0% Sunscreen), Octisalate (6.0% - Sunscreen)
Target Ultra
Sunblock SPF 30
Inactive Ingredients: Water, Aloe
Vera Gel, Mineral Oil, Stearic Acid,
Propylene Glycol, VP/Eicosene
Copolymer, Triethanolamine,
Acrylates/C10-30 Alkyl Acrylate
Crosspolymer, Cetyl Alcohol, Glycol
Stearate, Phenoxyethanol &
Methylparaben & Ethylparaben &
Butylparaben & Propylparaben,
Disodium EDTA.
When the sun’s rays are
more direct, we get more
intense rays.
We get more solar insolation in the
summer months also because
the sun has less atmosphere to
travel through if it is overhead.
If there is more atmosphere to
travel through, less radiation
reaches the surface.
So, is it easier to get a
sunburn when the sun is
overhead, or when it is on
the horizon?