Science IntroductionObservations- perception or notification based on your five sensesInferences- interpretation of an observationMass- the amount of matter in an objectVolume- amount of space and object takes up or occupiesDensity:Mass/volumeObjects that are less denser than water will float and objects that are more denser than water sinksIf a solid material heats up and expands, the density will decrease. WHY? The    volume changes. HOW to solve these types of problems (any density problem):1. What are they focusing on (what is changing)? The mass /volumeAstronomy Origin Vocab:Celestial Object: from earth it is anything above or outside the earth’s atmosphereUniverse- any matter that exists in any placeThe Big Bang TheoryWhat is the Big Bang Theory:Initiated in a small area of concentration and the area of matter and energy exploded within a short time (nano second). The universe, solar system,    and milky way formed billions of years later.Evidence:Radiation coming from several directions (background radiation) is evidence that supports that the universe began with an explosionRed shift (celestial objects moving away from earth and signifies that earth is still expanding)Stars also emit radiation Universe’s Origin & ½ Astronomy UnitThe universe is at least twice as old as our solar system. The universe is about 10 billions years old. The solar system is about 5 billion years old. The Milky Way Galaxy is ALWAYS located on the arm of the galaxy in the SIDE VIEW of the galaxy. In other views of the milky way galaxy that is not the SIDE VIEW, the point of earth is very nearby the arm, usually NOT on the arm. Galaxies move away from each otherNuclear Fusion- combines the nuclei of smaller elements in the    star and forms a bigger nucleus causing the build up of amounts of energy. This process occurs only in high temps. & pressure. It is caused OR initiated by hydrogen molecules. 2 hydrogen = helium + energy The sun is fueled by hydrogen and the sun is a star that uses this process (nuclear fusion). Light Years- the measure of distance used by astronomers Stars initiate from a nebula & the life cycle of stars depends on MASS AND SIZE.Temperature of stars are determined by color. Luminosity is the brightness of a star or stars.Stars- large balls of gas Star Types:Main Sequence-    Luminosity ranges from red to blue; as luminosity increases, temp. increasesGiant Stars- High luminosity; low temps; SUPER GIANTS- highly luminous; high temps. White Dwarfs- lower in luminosity; high temps; BLACK DWARFS- just dead! Stars end in nebulas or in black dwarfs.Asteroids: solid, rock-like    bodies that orbit the sun and falls to earth & orbits Mars & JupiterAs meteroids pass thru the earth and vaporize are called meteors. It causes an impact crater.Impact Events: collisions    (I.E. hitting the earth) by celestial objects such as asteroids, meteroids, meteors