5.1$The$Nature$of$Heat 5.2$Heatand$Temperature$ › 2 nature of heat presentation.pdf · Write$down$the$boldednotes We$will$review$heattransfer$ Correctyour$Quick$Quiz#1$

5.1 The Nature of Heat 5.2 Heat and Temperature

Science 14 and 10-‐4 with Mrs. M

Why does hot air rise?

•  Heat transfers from hot to cold objects •  Cold air is more dense and falls down

•  Hot air is lighter because it is less dense (hot air expands)

Write down the bolded notes

We will review heat transfer Correct your Quick Quiz #1

ConducNon •  Direct contact •  Objects must touch

•  Requires physical contact of object

ConvecNon

•  heat transfer by flowing current in fluids (liquid or gas)

RadiaNon •  Heat transfer by rays or waves •  Hot air radiates away from the source

FricNon

•  FricNon is the resistance that one surface or object encounters when moving over another

•  Push two things back and forth = resist each other

•  Heat results from fric1on

•  Example: rub your hands together to get warm

Brownian MoNon

•  Robert Brown (1800s) noNced that even if a microscope is very sNll, parNcles on the slide sNll seem to move around in the liquid.

•  If you heat up the slide, the moNon increases

•  Brownian mo1on is the jiggling or vibra1ng mo1on of par1cles

Rainbow Milk

•  It moves!

Par1cle Model of Ma<er

•  All ma<er is made up of par1cles •  Par1cles are in constant, vibra1ng mo1on

Thermal vs. KineNc Energy

•  Thermal energy = heat •  Kine1c energy = mo1on

•  More heat = more moNon

•  Temperature = the average of all kine1c energies

How Does Temperature Affect Brownian MoNon?

•  Temperature is related to heat because more heat causes parNcles to move faster. This increased kineNc energy means a higher temperature.

•  Hoaer temperatures means more Brownian moNon, or more vibraNon of parNcles

•  Cooler temperatures means less moNon

TRIVIA!

•  Split into three groups

What surface has more fricNon?

•  Ice or a grass field?


•  Pool table or air hockey table?


•  Glass or carpet?

Is this convecNon, conducNon, or radiaNon?









What does the parNcle model of maaer state?

What is Brownian MoNon?

Temperature is the average of what kind of energy?

Tie-‐breaker (?)

How Does Temperature Affect Brownian MoNon?

Thank you for playing TRIVIA!!!

How Does the Teabag Rocket Work?

ConvecNon Current

Hot Air Rises. This experiment demonstrates that idea as well as the principles of convecNon currents. As the tea bag burns, hot air is being created, as well as a thermal, or convecNon current, under the bag. When the tea bag burns down into a small enough ball of ashes, the convecNon current causes it shoot up in the air

Documents

5.1$The$Nature$of$Heat 5.2$Heatand$Temperature$ › 2 nature of heat presentation.pdf · Write$down$the$boldednotes We$will$review$heattransfer$ Correctyour$Quick$Quiz#1$