Friday sound The Doppler Effect Tone Generator Frog

Friday

sound

The Doppler Effect Tone Generator

Frog on a moving lily pad

the doppler effect

The Doppler Effect Video: The Doppler Effect (1: 56)

The Doppler Effect What does the Doppler effect have to do with stars?

color & wavelength in nanometres 700 red 650 orange 600 yellow 550 green 500 blue 400 indigo violet

white light hydrogen helium neon emission spectra

red-shift blue shift laboratory spectrum of sodium RED red shift blue shift BLUE

red-shift blue-shift

Explore questions… http: //curious. astro. cornell. edu/cosmology. php

The Big Bang Theory Warmup: Explain the spectrum: Today Discussion & Video: “Back to the Beginning”

Doppler Shift blue-shifted object –moving towards red-shifted object moving away

The Balloon Analogy

The Raisin Bread Analogy

Three important observations 1. The expansion of the Universe. § Hubble: galaxies are receding. 1 st evidence 2. The abundance of light elements (H, He, Li) § B. Bang theory predicts these elements should have been fused from protons and neutrons in the first few minutes after the Big Bang. 3. Cosmic Microwave Background (CMB) Radiation n The early universe should have been very hot. The CMB radiation is the remnant heat leftover from the Big Bang.

Cosmic Microwave Background

Big Bang Timeline We are here

Common Misconceptions n n The Big Bang was an explosion. The universe began as a point. The universe is expanding into “something” and we are at the center of the expansion. Galaxies are “flying away” in space.

Predictions of a Big Bang Universe I: Hubble’s Law n n Every point is receding away from every other point. Every point seems to be at the center of an expanding universe. The farther away something is, the faster it is receding (unlike an explosion). n n Farther away looks redder (Doppler effect) Relationship is linear: twice as far receding twice as fast.

Big Bang websites n n n For 2 students (& others? ) http: //www. astro. ucla. edu/~wright/doppler. htm http: //science. howstuffworks. com/big-bang-theory. htm “print” button -- this and next few pages http: //map. gsfc. nasa. gov/universe/bb_concepts. html http: //map. gsfc. nasa. gov/universe/WMAP_Universe. pdf http: //cosmology. berkeley. edu/Education/IUP/Big_Bang_Primer. html http: //curious. astro. cornell. edu/cosmology. php Have students spend ~30 minutes reading through the questions. Write (1) new understandings (2) new questions http: //www. amtp. cam. ac. uk/user/gr/public/bb_home. html http: //curious. astro. cornell. edu/cosmology. php http: //www. umich. edu/~gs 265/bigbang. htm