Light Phenomena Around Us

Transcription

1 Light Phenomena Around Us

2 Crepuscular Rays aka twilight rays or heaven rays Saint Peter s Basilica, Vatican City Detail of gold throne panel of King Tutankhamun, Egypt, BC

3 By: Albert Phases of the Moon It takes our Moon about 29.5 days to completely cycle through all eight phases: Since the Moon orbits Earth, the Moon gets Sun. When the Moon orbits, the Sun is shining on one side of the Moon and the other is dark, invisible to the naked eye. New (also called the Dark Moon) - not visible. Waxing Crescent First Quarter - commonly called a "half moon. Waxing Gibbous Full - we can see the entire illuminated portion of the moon. Waning Gibbous Third Quarter - another "half moon", but the illuminated part is opposite of the First Quarter. Waning Crescent New - back to the beginning!

4 Total eclipse of the Sun A total solar eclipse is a type of eclipse that occurs when the Moon passes between the sun and Earth, and the Moon fully blocks the Sun. By Aaron This can happen only at new moon when the Sun and the Moon are in conjunction as seen from Earth in an alignment referred to as syzygy. In a total eclipse, the disk of the Sun is fully obscured by the Moon. The next solar eclipse will occur August 21, 2017.

5 SUN Solar Eclipse Next one coming up August 21, 2017!

6 Colors of the Stars By Sofia You look outside at night and you see billions of stars. They seem white but they aren t, they are all different colors. Let s take a look at them. Red Stars (M): Coldest of the stars. T < 3,500 Kelvin Can be supergiant, normal or dwarf Normal and dwarf red stars are less in mass than other stars Supergiants are enormous compared to the Sun Examples: Betelgeuse (Supergiant) and Antares (Supergiant) Orange Stars (K): Not as cold as red stars, they are 3,500-5,000 K Can be supergiant, normal or dwarf People mistake that the Sun is an orange star Examples: Arcturus (Supergiant) and Aldebaran (Supergiant) White-Yellow Stars (G): Average stars, in mass, temperature, light glow, and size Temperature is 5,000 to 6,000 Kelvin Examples: Polaris (supergiant) and our Sun (white-yellow dwarf) White-Blue Stars (F) Not the hottest of the stars, but still very hot. Temperatures about 6,000-7,500 K These stars are big in size. Examples are: Canopus (supergiant) and Procyon (Sub-giant) The Three Types of Blue Stars (A, B, O) The A stars are the coldest of the blue stars. The temperature is 7,500 to 11,000 K The A stars are the smallest. They are also the third rarest stars. The B stars are rare but not the rarest (ex. Rigel in the constellation Orion) Temperatures in a B star range from about 11,000 to 25,000 Kelvin O stars are very uncommon, there are only a few (ex. 10 Lacertra) The temperatures are over 25,000 K and the luminosity is very bright

7 Colors of the Stars

8 How a Diamond Sparkles By: Mark Sasanuma What Makes a Diamond Sparkle? Key Idea: Reflection When a light ray falls on it, it reflects everywhere in a diamond. Why are Diamonds so Special? Because of their refractive index, which is the highest among jewels making it very popular for many women!

9 What Makes a Diamond Sparkle?

10 By Sophie Lightning Lightning is a sudden electrostatic discharge that occurs during a thunderstorm. What causes Lightning? Collisions between pieces of ice within a thundercloud. This builds up electrical charge. Gradually, the whole cloud will fill with electric charges. Positively(+) charged particles will form at the top and negatively(-) charged particles at the bottom. A giant spark, lightning will occur between the positive and negatively charged particles. Most of lightning happens inside the cloud but occasionally it happens between the cloud and the ground.

11 Lightning

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13 Fireworks

14 By Ari

15 It occurs widely among animals (many creatures of the open sea, and insects) as well as in some fungi and bacteria. Bioluminescence Bioluminescence is emission of light by a living organism by means of a chemical reaction (type of Chemiluminescence).

16 Flames By Savanna Pineros A flame is the visible part of the fire. It is an exothermic reaction, which means that it gives off heat.

17 Why Do Stars Twinkle? The scientific name for the twinkling of stars is astronomical scintillation or stellar scintillation. Stars appear like little tiny dots in the sky. As a star s light travels through Earth s atmosphere it gets refracted many times in all different directions. The random refraction causes the star to seem as if it is moving slightly. The human eye interprets it as twinkling. By Waela

18 Twinkle, twinkle, little star The scientific term is astronomical scintillation. Observed from the Earth, a star is essentially a pin-point light source. As starlight travels from space into the Earth s atmosphere, the rays are refracted. Since the atmosphere is constantly changing due to turbulence, the amount of refraction also constantly changes. This causes the image of a star to form in a slightly different part of our eye retina every moment we perceive it as twinkling. Planets usually do not twinkle why? You might actually see a planet twinkling if it appears low at the horizon why?

19 Aurora (Northern Lights) The aurora forms when charged particles emitted from the Sun (solar wind) get caught up in the Earth's magnetic field and collide with atoms and molecules in the top of the atmosphere. Different colors of the aurora are produced by different atmospheric components: Red oxygen atoms at ~200 miles high Blue ionized nitrogen molecules Green-Yellow oxygen atoms at ~60 miles high most common! Pink/crimson/purple mix of the above

20 Iridescence