Conceptual Physics Alive: Vibrations and Sound, Radioactivity, Fission and Fusion
Paul Hewitt teaches about Vibrations & Sound, Radioactivity and Fission & Fusion.
Master teacher Paul Hewitt teaches Conceptual Physics. Observe Hewitt teach in a classroom with real students, using engaging demonstrations and artwork.
DVD Includes 4 Episodes:
Episode 1: Vibrations and Sound I: A coiled toy is used to illustrate the difference between transverse and longitudinal waves. Interference of waves and beats of sound are also demonstrated, followed by an explanation of shock waves and sonic booms. Segment length: 32 minutes
Episode 2: Vibrations and Sound II: The reflection, refraction, and speed of sound waves are explained. A discussion of forced vibrations and resonance culminates with exciting historical footage of the collapse of the Tacoma Narrows Bridge in 1940. Segment length: 43 minutes
Episode 3: Radioactivity: The differences between alpha, beta, and gamma radiation are discussed, with emphasis on balancing nuclear equations. Radioactive half-life and techniques for radioactive dating are also explained. Segment length: 40 minutes
Episode 4: Fission and Fusion: Fission and fusion are distinguished and compared. Energy release from nuclear reactions is explained in terms of the resulting mass defects. Muon-induced cold fusion is briefly discussed. Segment length: 36 minutes
Vibrations and Sound I includes:
• Wiggles and jiggles.
• Vibrating chalk at chalkboard illustrates low and high frequencies of vibration. Waves are illustrated when Hewitt walks across the floor to trace out a sine curve.
• Amplitude and wavelength of a wave.
• Derivation of wave speed.
• All electromagnetic waves have the same speed, c = 300000 km/s.
• Radio-wave wavelengths are calculated for different frequencies.
• Demonstration of slinky vibration to show longitudinal waves; then transverse waves.
• Ted Brattstrom demonstrates wave characteristics on an oscilloscope.
• Wave interference is illustrated on the chalkboard.
• Hewitt pretends to demonstrate interference by striking a pair of tuning forks out of phase so that the sound from one is canceled by the sound from the other.
• Beats are defined.
• Demonstration on the oscilloscope of beats from a pair of tuning forks of slightly different frequencies.
• Laser discs (CDs).
• Technological changes discussed, and Hewitt leaves with the question, "What will replace windshield wipers?"
Vibrations and Sound II includes:
• Hewitt begins with a chalkboard discussion of the waves generated by a bug that bobs up and down on a smooth surface of water.
• Doppler effect.
• Bow wave.
• Shock wave and sonic boom.
• Mach numbers and the speed of sound.
• Bullets, shock waves, and mini sonic booms.
• Crack of a circus whip; a mini sonic boom.
• Speeds of sound in air, water, and steel compared.
• Ultrasound and its application for medical use.
• Dolphins and ultrasound.
• The molecule-to-molecule conduction of sound.
• Sound propagation, density, and elasticity.
• Sound refraction.
• Interference of sound and its application to tomorrow's jack hammers.
• Demonstration of tuning forks.
• Demonstration of a music box piece that sounds louder when pressed against a sounding board.
• Forced vibration.
• Examples of resonance; kid on a swing in Golden Gate park, loose front end of Hewitt's car, radios on glass shelves, hotel balcony collapse, bridge collapse.
• Hewitt's story (with lies!) of the devastating effect a cat would have on the George Washington Bridge in New York.
• Footage of the famous 1940 Tacoma Bridge collapse ends the lecture. Hewitt continues spoofing about a cat causing the collapse, then directs his class to look in his textbook for the better explanation [of wind generated resonance].
• Hewitt begins with X rays and their nature.
• Three types of radiation.
• Alpha (helium nuclei) Beta (electrons) Gamma (electromagnetic)
• Why atoms are radioactive.
• Strong nuclear interaction.
• Neutrons as nuclear cement.
• Why a nucleus cannot be too big and be stable.
• Nuclear nomenclature: Helium Lithium Uranium
• Isotopes defined.
• Source of earth's heat.
• Uranium series to lead.
• Radioactive half-life defined.
• Nuclear transmutation defined.
• Nuclear reactions: Uranium and alpha emission Thorium and alpha Beta emission.
• Rutherford's historic transmutation experiment.
• Carbon dating.
• Old-axe-handle story.
• Decay rates.
Fission and Fusion includes:
• Hewitt begins with a historical perspective of atom smashers.
• Sample fission reaction.
• Small mass particles for moderating neutrons.
• Energy comparisons.
• Reactions of U-238, U-239, and Np-239.
• Bombs dropped on Japan during World War II.
• Mass model for energy release of fission.
• Mass/nucleon for the elements.
• Chalkboard graph of nuclear mass versus atomic number.
• Contrast with graph of mass/nucleon versus atomic number.
• Skit of shaking nucleons to describe graphs.
• Work required to remove a nucleon from a nucleus.
• Fission of uranium and E = mc2.
• Power production via fission.
• Radioactivity of fission fragments.
• Nuclear fusion.
• Typical fusion reactions.
• Energy conservation at the nuclear level.
• Iron is the nuclear sink.
• Fusion of iron in a star and star cooling.
• Solar conversion of 4 1/2 million tons of mass to radiant energy per second (Correction to tape: That's 4 1/2 million, rather than 4 1/2 billion as said in lecture.)
• Fuel for fusion — abundant hydrogen.
• Laser induced fusion.
• Cold fusion, muon-induced.
• Breeder reactors.
• Speculations of a fusion age.
• Apprehension of the future and Hewitt's analogy of his childhood experience of not knowing how to tie his shoes and worrying about social disapproval in later years.