Birth of a Theory 1.3 p. 14-17 Once a hyposthesis has been tested…and tested….and tested…It might be moved into the realm of being a theory.

Theory and Law Theory Scientific Law A hypothesis that is accepted. Has been supported again and again by science. Can be changed if new evidence emerges. Scientific Law A well established theory. Theory that has been proven corrected every time it is tested. A rule of nature Conservation of mass Universal gravitation Theories and laws differ.

Spectrum Light is broken down into individual colors when passed through a prism Roy G. Biv Science has used sci method and observation to provide us a lot of information to for the theoried we have today. Newton observed that light passing through a prism created a rainbow called the spectrum.

Wavelength Distance from the crest of one wave to the crest of the next wave. Shorter wavelength = higher energy As light is bent it is divided into it’s individual wavelenths. Red is the longest wavelenth, blue is the shortest. Blue = high energy, red = low energy.

Bright Line Spectrum When elements are heated they create their own unique spectrum. Fingerprint Individual elements also have a unique finger print. That is how we can tell what elements we see in the stars. We can analyze the light coming from the star and compare it to the finger prints of known elements. We are going to look at the fingerprints of some known elements.

Bright Line Spectrum Each group needs: Paper and colors: Red, Orange,Yellow, Green, Blue, Purple (or close to those colors)

Doppler effect The apparent shift in the wavelengths of energy emitted by an energy source moving away from or toward an observer. Light coming from a source will appear shorter or longer depending on the movement of the object. Have you ever noticed the sound a car makes as it passes? High pitch as it approaches and lower as it passes? When the sound is coming toward you it seems to sound different. It also sounds different as it passes. To the person in the car the sound stays the same. The same phenom. This is how we can tell is a star or group of stars is moving toward or away from earth. As the energy from the star approaches earth it’s spectrum will appear to be shifted to either the red or blue side of the spectrum. This is the doppler effect.

Spectroscope An instrument used to study the light from stars to determine the elements present. Breaks up light into individual wavelengths. A spectroscope is used to analyze the light of stars.

Red Shift The spectrum of light is shifted toward the red side. Wavelengths appear longer Object is moving away from us.

These galaxies show red shift. Looking at the spectrum coming from galaxies shows most are moving away from earth. They can also calculate the rate at which they are moving away. This is one piece of evidence that leads us to believe that the Universe is expanding.

Big Bang Theory Theory to explain the origin of the Universe. All matter and energy was condensed into one dense, small volume. ~15 billion years ago all the matter and energy suddenly expanded outward to start forming the universe.

The big bang explains how the first elements were formed The big bang explains how the first elements were formed. As we will see later this led to the formation of the stars…and…all other naturally occuring elements. Yes, even those that make up elastic banded undergarments.

But seriously… Inflation: Hot and dense. Grew by a factor of 10^50 in a fraction of sec. Quark soup: cooled enough to enable the formation of basic subatomic particles. Protons, neutrons and electrons. H exists. Big freeze: temp cooled enough to enable subatomic particles to stick together. Creating He. Parting company: left over radiation from initial big bang starts cooling. This radiation is what was predicted by Gamov in 1948 but detected in the early 60’s by Penzias and Wilson. Early theorists of the the big bang theory new the left over radiation had to be present….where could it go? They also know because of the doppler shift that the radiation would have since shifted into the wavelenths of microwaves. First Galaxies: Slowly the particles through gravitaional attraction start to condense, form clouds(nebula), galaxies and the stars they contain. Modern Universe: planets were problably formed around the same time as stars. The Earth and our solar system formed much later after the big bang. It s estimated that our solar system in only ~4.5 billion years ago. http://archive.ncsa.illinois.edu/Cyberia/Cosmos/CosmicMysteryTour.html

Penzias and Wilson found what? Penzias and Wilson discovered a microwave hiss that was interfereing with communications. Although they were the first to discover it, they didn’t realize what they had discovered.

Evidence to support the theory Red shift shows an expanding universe Background radiation was found evenly distributed throughout the universe. Discovery of the radiation dates the universe to be ~b5 million years old. Like all theories, as new information is learned the big bang theory may be revised or a new theory could take it’s place.

Like raisins in expanding bread, the galaxies are move from each other in an expanding universe

Big Bang Balloon Lab