Princeton University Science & Engineering Expo

Welcome to the Physics Department!

17 Mar 11 Physics Department

Princeton University

Professor Suzanne Staggswith Omelan Stryzak

ENERGYEnergy is the capacity or ability to do work, and comes in many forms: •KINETIC ENERGY (moving things)

•GRAVITATIONAL ENERGY (things about to fall down)

•ELECTRICAL ENERGY (electricity)

•RADIANT ENERGY (glowing things)

•SOUND ENERGY (noisy things)

•MECHANICAL ENERGY (springy things or things under pressure)

•WAVE ENERGY (waves)

•MAGNETIC ENERGY (magnets)

•HEAT (hot things)

•CHEMICAL ENERGY (things that could explode)

One of the key principles of physics is that energy

is CONSERVED, so that mechanical energy can

be converted to electrical energy, for example.

The demonstrations today all involve conversions

of energy from one form to another, sometimes in

a spectacular manner….

ENERGY CONSERVATION: The Nose Basher

KINETIC ENERGY <---> GRAVITATIONAL ENERGY

ENERGY CONSERVATION: The Nose Basher

KINETIC ENERGY <---> GRAVITATIONAL ENERGY

ENERGY CONSERVATION: The Nose Basher

KINETIC ENERGY <---> GRAVITATIONAL ENERGY

POWER = ENERGY/TIMEThe Bicycle Generator

1 Watt = 0.9 Calories/hour1 Candy bar/5 minutes = 3800 Watts

Lightbulb …………...……….. 100 WattsCar at 60 mph …. 20 kW = 20,000 WattsPower Plant …... 1 GW = 1 billion Watts

KINETIC ENERGY <---> ELECTRICAL ENERGY

ENERGY CONSERVATIONFormula Zero uses BOOSTCAP® Ultracapacitors. These are supercapacitators with a rated power of 50 kw, and used to store excess energy produced by the fuel cell or during braking procedures. This energy can be used to quickly accelerate out of corners or when passing other drivers.

ELECTRICAL ENERGY <---> RADIANT ENERGY ++

CAPACITORS

ENERGY CONSERVATION

VORTEX CANNON

(make your own -- no smoke -- by banging on the bottom of an empty gallon milk container --

surprise your pet cat with a puff of air!)

MECHANICAL (SPRING) ENERGY <---> WAVES

ENERGY CONSERVATION

SOUND ENERGY <---> KINETIC ENERGY

The Great Ball Race

ENERGY CONSERVATIONMAGNET HOLDING ALL THESE TOOLS …

MAGNETIC ENERGY <---> KINETIC ENERGY

ENERGY CONSERVATION

THERMAL/CHEMICAL ENERGY <---> RADIANT ENERGY

ENERGY CONSERVATION

MECHANICAL (PRESSURE) ENERGY <---> KINETIC ENERGY

ROCKET CAR

Thank you for coming. Conservation of energy, as the term is used in everyday speech, requires your help. Use energy wisely. Have a good day. Don’t forget to convert some of your chemical energy into kinetic energy and thermal energy through exercise every day. -- STS

END

Energy: the ability to do work

Object Energy per gram (Calories/gram)

speeding bullet 0.01

TNT explosive 0.1

sugar 4

butter 8

gasoline 10

hydrogen 26

uranium 20 million(!)

Adapted from Prof. Richard A. Muller, U.C. Berkeley

ENERGY CONSERVATION

ELECTRICAL ENERGY <--->CHEMICAL <---> GRAVITATIONAL ENERGY