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Department of Physics

HOOOOOOT TUBESObservations:

-many places at once-goes around corners-focus (collect) sound-adds in peculiar ways

Sound is a WAVE.

Examine a wave on a string

TRANSVERSE WAVEString up and down Wave left and right

In general sound is complex. (Display Song)

Special waves are simple. (Display Note)Harmonic or sine waves.

SoundPressure wavetravels through a mediumLongitudinal wavefrequency range few Hz - 20kHz

~ Bed of nails

~ Tug of War

• The best way to understand what energy is, is looking at its different forms.– What are the different forms of energy?

• Energy cannot be created or destroyed – it can only change from one form to another

• Lets see if we can identify each type of energy in these demonstrations– Potato gun, tennis ball cannon

– Tubes, Tuning fork

– Bouncing balls, rotating platform

– Capacitor

– Gas model

• Remember, energy is always conserved so one form of energy must flow into another.– Gas model : electrical & motional motional

& thermal– Food : stored chemical energy motional– Tubes : motional sound– Capacitor : stored electrical energy– Tuning fork : motional sound

~ Magic Pictures

Light has two polarizations.

Filters can pass one type and block the other.

Examine the light from a standard bulb. (free glasses!)Filament heated until it glows like the sun.

Color depends on the temperature.

• A hot body has a continuous light spectrum

• Red light has less energy per photon than violet light

~ Atomic Spectra

Light sometimes acts as a wave.Special waves (harmonic waves) frequency (color)amplitude (brightness)

Examine light from excited atoms.

Only certain colors are found.Each atom has its own unique pattern or Atomic Spectrum.

• The nucleus contains:– Protons

– Neutrons

• Electrons orbit the nucleus at different energy levels

• Analogy: People in the bleachers of a stadium!

• One element is different from another because their atoms are different !

• That means that the hydrogen atom must be different from the carbon atom

• The hydrogen atom 1 electron, 1 proton• The hydrogen atom 6 electrons, 6 protons, and

6 neutrons

- The molecule (substance)

doesn’t change

- The molecule (substance)

changes identity

Amount of water……………………….ChargeWater pump………………………………BatteryReservoir…………………………………..GroundHeight of Water.……….………………VoltageWater flow ………………………………..CurrentSize of tube……………………………….Resistance

.

• Why the arc is created Why the arc moves upward - ionization of the air - causes the air to heat up - the charge goes through the path of least resistance• Why the arc stops

• Belt carries charge to aluminum sphere

• Large electric field at the point of each pin– Same with a lightning

rod

• Is like a battery

                  

.

1. Ball and Meter Stick 2. Confetti Cup 3. Experimenting on a Volunteer

.

• 300,000 volts! - Any volunteers?• High frequency keeps the current from

penetrating your skin - charge should reside on the outside of your skin• Theory states that one should be able to light up a fluorescent tube!

Magic tube

How does this work ?

Electric currents are pushed and pulled by Magnetic fields.

Changing Magnetic fields create electric currents.

-Charge up giant capacitors.-Discharge quickly through a coil

creating a changing magnetic field.-Electric current moves around the can

(due to changing magnetic field).-The magnetic field pushes the current

and therefore the can.

Russ the Squirrel says...

Don’t try this at home!

•JMU Physics…– Dr. Peterson– Dr. Giovanetti – Dr. Whisnant– Andrew Werner– Kevin Finnegan– Karen Bland

–Will Quarles–Charles Arnold–Chris Church–Erin McGrath–Amelia Cohen–Seth Henshaw