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Warm-up Josie wants to find out if beeswax candles burn faster than regular candles. What is the independent variable? The dependent variable? Max wants to test the speed of a motor with a 9 volt battery and a 24 volt battery. What is the independent variable? The dependent variable?

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Heat (SOL 7) Chapter 2, pages 50-56 (change of state) and Chapter 4 (kinetic theory of matter, temperature scales, thermal expansion, energy flow, convection, conduction, radiation)

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HEAT!! And change of state The speed at which atoms move is called? Kinetic Energy!

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If the pressure stays the same, Everything expands when heated and shrinks (contracts) when cooled Except... Water!!! Water expands when it cools!!!!

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Kinetic Theory of Matter Matter is made up of particles which are in continual random motion.

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hot liquid cold liquid

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Temperature Temperature is the Measurement of how fast molecules are moving.

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Celsius the SI unit for temperature 0 is freezing point of water (at sea level) 100 is boiling point of water (at sea level) Do I have to know this? YES!!!

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Farenheit Freezing is 32 degrees Boiling is 212 degrees. Do I have to know this? NO!!!

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Kelvin Freezing point is 273 Boiling point is 373 Why these crazy numbers? Because in the Kelvin scale 0 = absolute zero. The temperature at which all matter turns solid. (freezes) and motion stops. Do I have to memorize these numbers? NO!!!!

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Temperature Game

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How does a thermometer work? When something becomes hot, its molecules move faster and take up more space. (It expands). When the liquid in a thermometer gets hot it expands and moves up!

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How it works

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Moving atoms move atoms The transfer of this motion of atoms/molecules is called HEAT. This energy flows from where it is HOT to where it is NOT. Even cold things have heat energy! What is an example of heat going from where its hot to where its not? ice heat

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How do hats and gloves work?

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Matter Can Exist in Different States: ENERGY, Pressure & Volume

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Properties of Water Water coheres, which means water molecules are atrracted to each other. Why? Because one end of a water molecule has a positive charge And the other end has a negative charge so there is magnetic attraction.

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Coheres sticks to itself Causing Surface Tension

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THATS A FACT ---- Water is the only substance that can be found as a solid, liquid and gas at normal surface temperatures on Earth.

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Change of State When a substance changes state (solid, liquid, gas) its identity does not change and the process can be reversed. All three of these Pictures are of iron in different States.

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Warm-up 1.What holds more heat a glass of water or a lake (if they are at the same temperature) 2.What is the name for the process by which a liquid becomes a solid? 3.What is the SI unit of measurement for temperature? 4.In the heating curve on the right, what is the boiling point temperature? 5.What letter is the melting point? 6.What letter represents a gas? 7.What is the freezing point? 8.What is the condensation point? 9.What is the difference between Conduction and convection? 10. What is absolute zero?

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Change of State: Heating matter ADD ENERGY (heating) and atoms can speed up enough to change state: Melting solid changes to liquid. The temperature at which this happens is the melting point.

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Why doesnt wood melt? Heat of combustion is lower than the melting point. (Combustion is the temperature at which something burns). Some things burn before they melt

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Vaporization a liquid is heated and turns to a gas

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Two kinds of vaporization: 1. Evaporation occurs only at the surface of a liquid.

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2. Boiling is vaporization that occurs throughout a liquid. **Boiling point is the temperature at which boiling begins.

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MatterMatter Brainpop-States of MatterBrainpop-States of Matter

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Sublimation solid turns to a gas (no liquid phase)

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Change of State (Cooling) REMOVE ENERGY (cooling) and atoms move slower, this can cause a change of state Condensation a gas becomes a liquid. Freezing A liquid becomes a solid.

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Cooling Curve

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Heating and Cooling curves on the same graph

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What Determines the State of Matter? Energy of the Atoms (measured as Temperature) Energy Pressure on the Atoms Pressure Volume The amount of space the atoms are given.

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Thermal Expansion When an object is heated, its atoms move faster and take up more space so the size of the object expands Water is the exception. It gets smaller when heated and larger when frozen

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Asphalt

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Warm-up What do you think holds more heat? Which would be easier to increase or decrease the heat of? Why? Which of these heats up Faster? Why Rubber tire Copper Cube

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Heat... 1.Large substances hold more heat than smaller substances and its more difficult to change their heat. 2.Specific heat The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. What substances do you think have a high specific heat? A low specific heat?heat per unit mass required to raise the temperature by one degree Celsius.

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Atom Motion is Transferred Classzone - Conduction, Convection, Radiation Classzone ConductionRadiation

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Convection Currents Heat moves from where its hot to where its not Because hot fluids and gases are LESS dense than cold fluids and gases, they rise. Cold sinks Hot rises

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Convection Currents

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Earths Energy Budget 50% absorbed by earths surface 19% absorbed by the atmosphere and clouds 20% reflected by the clouds 4% reflected by the earths surface 6% reflected by the atomosphere