Unit 3: DCA Review Space

Seasons, Moon Phases, and Tides

Draw and label the moon phases.

Define the following words: Waxing: Growing Waning: Shrinking Gibbous: More than half Crescent: Less than half

What causes day and night As the earth rotates counter clockwise on a 24-hour time schedule, its east and west hemispheres alternate facing the sun causing day and night Day Night

Four Seasons

Explain what season it is in the northern hemisphere compared to the southern hemisphere. They are always the opposite What season is it in the southern hemisphere?

Explain why some areas of the Earth’s surface are warmer than others at different time in the year. Because the earth is tilted on its axis, part of the earth is either facing towards the sun or leaning away from the sun This is what creates seasons and varying day length

Draw Spring Tide, what moon phase it it?

Draw Neap Tide, what moon phase is it?

Tides It takes earth one day to have a full rotation, so there are two high tides in a day and two low tides Each high and low tide are 6 hours apart

Regardless of the phase, how much of the earth and moon receives light from the sun at any given time? Half of the sun and earth

Define the following: Rotation: the earth spins around the axis Revolution: The earth circles the sun Tilt: The earth’s axis is tilted 23.5 degrees Axis: An imaginary line that runs from the north pole to the south pole

Components of the Universe

How are stars classified? Stars are classified by three main characteristics: 1.Size 2.Brightness 3.Temperature

6. What is a galaxy, and what are 4 types of galaxies? Galaxies are made up of millions of stars, gases, and dust that are all held together by gravity Elliptical Spiral Lenticular Irregular

Hertz-Russell Diagram Main Sequence: 90% of all stars Absolute magnitude (brightness)

What color are the hottest stars? Coolest? Hottest: Blue Coolest: Red

Nebula A hot clouds of gas, that serves as a birth place for stars

Protostar 2.Protostars: beginning formation of a star when gravity pulling together the dust and gases until they get hot enough to fuse together

Main Sequence Adult life of a star, 90% of stars become main sequence stars and burn through their hydrogen (to make helium) slowly

Death of a star Small –Medium Stars: RED GIANTS 1.As they run out of fuel, their outer layer begins to expand and they become RED GIANTS WHITE DWARF 2.When the outer layer drifts into space, only the hot core is left forming a WHITE DWARF BLACK DWARF 3.When the white dwarf stops glowing it becomes a BLACK DWARF

Death of a star Large Stars: SUPER GIANTS 1.Instead of forming a red giant, large stars form SUPER GIANTS SUPERNOVA 2.Super giants can suddenly explode creating a SUPERNOVA 3.Three outcomes to a supernova: 1.Recycled material makes a new star 2.Neutron Star can be formed: this is a very dense star (same amount of mass as the sun, but the size of Houston) 3.The star can become a black hole

Life of a Star Nebulae/ Protostar/ Main Sequence Red Giant White Dwarf Black Dwarf Small/Medium Size Star

Life of a Star Nebulae/ Protostar/ Main Sequence Super Giant Supernova Recycled Star Large Size Star Black Hole Neutron Star

The Sun

What is the name of the Galaxy that the Sun is located in and why type of galaxy is it? Milky Way: Spiral Galaxy

Where is the sun located in the galaxy? On the edge in an arm of the spiral

What color, temp., and size if the sun? Color: Yellow Temperature: 6,000*C Size: Medium

Our Sun’s Location in Solar System Solar system: It is the center of our solar system million Kilometers away form the earth –Closest star to earth

Electromagnetic Spectrum

Wavelengths Longest – Radio WaveShortest – Gamma Ray

How do astronomers use the EMS to determine elements in stars? Each element on the periodic table absorbs light at different wavelengths creating a “fingerprint” on the EMS Black lines show us the fingerprint Example of a “fingerprint” for Hydrogen

What observations can be made about wavelengths other than visible light?

What is red shift? If something in the universe has a longer wave length (red), than it is moving away from the earth Helps support the Big Bang

Light Years Light year: the distance light travels in one year –It is a unit of speed, not time –It is similar to miles per hour

Light Years The speed of light travels at 300,000 kilometers per second So, for every 1 second, light travels 300,000 kilometers

Big Bang Theory Most popular theory Says that at first matter was in one small area, and than it got so hot it exploded This theory suggests that everything is still expanding and growing

What supports the Big Bang Theory? Red shift - moving away from earth Red Shift shows that the universe is still expanding

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