Heat & Waves: Notes on HEAT ENERGY and WAVES including the difference between longitudinal, transverse, & electromagnetic waves with illustrations, LABS, and video links

Physics :HEAT & WAVES

ppt. by Robin D. Seamon

(Heat & Temperature / Energy Waves)

HEAT

SCIENCE SONGS

THERMAL ENGERGY=ATOMS MOVING!

•Temperature: average kinetic Energy of particles in an object

Solid

Liquid

Gas

http://www.bcssa.org/newsroom/scholarships/great8sci/Matter/Choose_Matter.html

The more kinetic E the higher the temp.

Add heat to change phases

Interactive LAB

PHASES

•Density: how close the atoms are in the element

SOLIDS: atoms are tightly packedmovement of atoms is small & rapid because of

the close bonds-definite volume & shape

LIQUIDS: atoms are farther apart than solids and can slip around each other faster

-definite volume; no definite shape so will take the shape of containerGASES: atoms are farthest apart and can move about freely. (unconstrained gases will spread out indefinitely; confined gases take shape of container.)

-no definite volume or shape

ELEMENTS:Different elements have different properties-

•Boiling point: point at which the atoms in a liquid state vibrate and become a gas (hot)

-different for each element!•Melting point: point at which the atoms in the solid state vibrate and become a liquid (hot)

-different for each element!

VIDEO: Making molecules with atoms (2 min)

Elements LINK SONG (3.5 min)

VIDEO: Energy Sources

VIDEO: Energy Flow (2 min)

VIDEO: How Electricity is Made (2 min)

Molecules in motion SONG (3 min)

Solubility: amount of a solute that can be dissolved in a solvent

-depends on the chemistry of it-depends on the temperature

of it (warm dissolves faster)

http://www.chem4kids.com/files/matter_solution.html

HEAT Labs

• Heat absorption

• Melting point

• Boiling point

• Solubility

•Thermometer: thin glass tube filled with mercury or alcohol

•Thermal expansion: temp goes up, volume goes up b/c particles spread out

examples: thermometer, hwy joints, bimetallic strips in thermostats

Kelvin Celcius Farenheit

373°K 100°C 212°F

310°K 37°C 98.6°F

273°K 0°C 32°F

Kelvin 0 = when all molecular motion stops

Thermostat:

•Conduit: conducts/ allows Energy transfer; water, metal

•Insulator: does not allow Energy transfer; fiberglass, cardboard, air, cork, wood, rubber, wood

•Heat: Energy transferred between objects at different temperatures; thermal EnergyIf two objects are connected, there is always transfer between high temp to low temp

•Thermal equilibrium Energy transfer until the same temperature on both (balanced)

Put ‘C’ for Conductor & ‘I’ for Insulator.

Curling ironoven mittceramic bowliron skilletstove coilcookie sheetplastic spatulafiberglass insulationcopper pipe

Why would we want an object to be an insulator?Why would we want an object to be a conductor?

•Conduction transfer of thermal energy through direct contact

•Thermal (warm object touches a cold object)

•Mechanical (kinetic E) 2 objects push or pull on each other

•Electrical (current) battery or generator is connected in a complete circuit to a device

•Convection transfer of thermal energy by movement of liquid/gas (hot up, cold down)

•Radiation transfer of thermal energy by electromagnetic waves (visible light & ultraviolet waves)

HOW DO OBECTS HEAT UP?

QUESTION: Which changes temperature faster: --air, water?

Can’t measure transferred E directly; must be calculated:

Heat (J) = specific heat x mass x change in tempVIDEO: Heat Transmission (3 min)

HSW video: Fiberglass insulation

VIDEO: RADIATION

VIDEO: Geothermal Power (2 min)

HSW video: THERMAL RADIATION universe (2 min)

HEAT experiment 5 card LINK: http://www.wisc-online.com/objects/ViewObject.aspx?ID=sce304

Materials:Sugar, hot water, cold water, spoon

Sugar Solution Lab

1. Define solubility: _____________________________________________2. In this experiment, which was the solute? _____________ Which was the solvent?

___________3. Which jar dissolved the sugar the fastest? _______________4. Which jar dissolved the most sugar? ______________5. Answer: Was your hypothesis correct? ________6. Explain why the sugar dissolved faster in the ______ water. (Use words from the

word bank.) __________________________________________________________________________________________________

7. What happened to the solution when you could not dissolve any more sugar in the solutions?________________________________

8. What does kinetic energy have to do with solubility? ____________________________________________________________________________________________

9. What would be the best way to make sweet tea? ________________________________________________________________________________________________

Variables:Independent variable- hot water, cold waterDependent variable- sugar, size of container, amount of water WORD BANK

SolventSoluteSolubilitySaturationMoleculesAtomsKinetic energyDensity

QUESTION: Does the temperature of a liquid affect the dissolving of a solute into a solvent?PROCEDURE:1.Prediction: In which solution do you think the sugar will dissolve best? ____________________2.Add the same amount of water to each jar (1 hot, 1 cold)3.Add a spoon of sugar to each jar. Stir.4.Add equal spoonfuls of sugar to each jar until no more dissolving is taking place. 5.Observe & answer the questions below.6.Cleanup.

LAB: Feel the Heat

Trial Mass of nails (g) Volume of water that equals mass of nails (mL)

Initial temp. of water & nails

Initial temp of water to which nails will be transferred

Final temp of water and nails combined

1

2

Procedure:

• Bundle the nails together with a rubber band. Record the mass. Tie string around, leaving one end 15 cm long.

• Put bundle of nails into a cup, letting string dangle out. Fill the cup with hot water, covering nails. Set aside 5 min.

• Use graduated cylinder to measure enough cold water to exactly the mass of nails. Record.

• Measure & record the temp of the hot water with the nails & temp of cold water.

• Use string to transfer the bundle of nails to the cup of cold water. Use the thermometer to monitor the temperature of water-nail mixture. When the temp stops changing record this final temp.

• Empty cups, dry nails. Repeat for trial 2, but switch the hot & cold water. Record data.

Conclusion:

The cold water in Trial 1 gained energy. Where did the E come from?How does the E gained by the nails in Trial 2 compare with the E lost by the hot water in Trial 2? Which material seems to be able to hold E better… iron or water?

p. 430

Materials: balance, 2 cups, cylinder, 10 nails, string, rubber band, thermometer, hot water, cold water

WAVES

SCIENCE SONGS

•Wave: disturbance that transmits Energy through matter or empty space;

--as wave travels it does work on everything in its path

•Mechanical waves: need a mediumexamples- sound wave, ocean wave

•Some waves don’t need a mediumexamples- visible light, microwaves, tv, radio signals, x-rays

Compression waves pressed close together

Rarefraction waves stretched farther apart

Example: sound wave

Rarefraction

Waves:

Transverse wave- particles move up & down, perpendicular to direction wave is going

Longitudinal wave- particle move horizontally along the wave in the direction the wave is moving

Surface wave- combination of transverse & longitudinal wave

VIDEO: HSW Wavelength Basics

ADVANCE

Transverse wave- particles move up & down, perpendicular to direction wave is going

BACK

Longitudinal wave- particle move horizontally along the wave in the direction the wave is moving

BACK

Surface Waves

HSW: Waves of Destruction Surface Waves (3 min)Video: Waves (2 min)

BACK

Properties of Waves

•Amplitude: maximum distance the particles vibrate

•Wavelength: distance between two crests or compressions in a wave

•Frequency: number of waves in a given amount of time

•Wave speed: speed at which wave travels (v)

Wave Interactions

reflection- wave bounces back after hitting a barrier;examples: light reflected lets us see itsound echoes

refraction- bending of a wave as it passes from one medium to another at an angle (because wave changes speed in a different medium)example:light through a prism (light is dispersed into separate colors)

Diffraction bending of waves around a barrier

Interference two or more waves overlap

-constructive interference 2 waves overlap crests & troughs, combining both waves’ energy… makes it stronger!

-destructive interference 2 waves overlap one crest on one trough, cancels out each other’s Energy

HSW: Assignment Discovery: Sound/Interference (1 ½ min)

Ripple Tank Simulation

Standing waves: pattern looks like wave is standing still

Resonance: two objects naturally vibrate at the same frequency; sound of one causes the other to vibrate

VIDEO: Sound/Resonance-Shattering glass (15 min) United Streaming

LAB: Musical Instruments

LAB: Musical Instruments

SCIENCE SONGS