General Announcements:
Energy/Heat unit Exam-
Thursday, October 30th
*In preparation for
this unit exam, you should be studying all notes, homeworks, labs and
quizzes.
*Extra help is available during your lunch period
Topics include:
Energy- potential and kinetic, 5 forms of energy
- Energy
exists in many forms, and when these forms change, energy is conserved.
- The
Sun in a major source of energy for earth.
- Different forms of energy
include: thermal, electromagnetic, nuclear, mechanical and chemical.
- Energy can be considered
to be either kinetic energy ,which is energy of motion or potential, which
depends on relative position and is stored energy
Heat, Temperature, Phase Changes
- During a phase change, heat energy is absorbed or released
- Energy is absorbed when a solid changes to a liquid and when
a liquid changes to a gas.
- Energy is released when a gas changes to a liquid and when a
liquid changes to a solid.
- During a physical change, a substance keeps its chemical
composition and properties. Examples of physical changes include
freezing, melting, condensation, boiling, evaporation, etc.
Heat and Temperature- heat capacity
- Atoms and molecules are perpetually in motion. The greater
the temperature, the greater the motion.
- Temperature is a measure of the average kinetic energy of
each particle within an object.
- Three temperature scales include Fahrenheit, Celsius and
Kelvin.
- Heat energy is the total energy of the particles that make up
an object (affected by mass and temperature)
- Heat capacity is the ability of an object ot hold heat and is
determined by its mass and the material it is made of.
- Temperature change = Final temperature – Initial Temperature
Heat Transfer: Conduction, Convection and Radiation
- Heat moves in predictable ways, flowing from warmer to cooler
objects, until both reach the same temperature.
- Heat is measured in calories.
- Temperature change (DT) = Final Temperature – Initial Temperature
- Heat can be transferred through matter by collision of atoms
and/or molecules (conduction).
- Through an empty space or a vacuum, heat is transferred as
electromagnetic waves (radiation).
- In a liquid or gas, currents will facilitate the transfer of
heat (convection) due to density differences. Hot gases or liquids
will rise because less dense and cold gases or liquids will sink because
more dense.
- A conductor (usually high density, solids, metals) transfers
heat well, whereas an insulator (usually low density) does not.
Thermal Expansion/Contraction
- Most objects will expand when heated and contract when
cooled. Water is an exception, expanding when changing to ice.
- When heated, molecules become excited, move faster, spread
out (less dense) and the object expands (thermal expansion).
- When cooled, molecules move slower, come closer together
(more dense) and the object contracts (shrinks)
The effect of heat on chemical reactions
- In
chemical reactions, energy is transformed into or out of a system.
Light, electricity, or mechanical motion may be involved in such
transfers, in addition to heat.
- Energy
cannot be created or destroyed, but only changed from one form to
another. In the process, some energy is always converted to heat.
- As
temperature increases, kinetic energy increases and the number of
collisions increase. As more collisions occur, the rate of a
chemical reaction will increase.
Energy Quiz #3- Thursday 10/9
Topics include:
Labs-
1. Shaking it Up lab pg 29-30
2. Effect of Heat on
Matter Graph and questions
3. Phase changes pages
83-87
4. Difference between
Temp. and Heat p. 37-39
5. Conductor/Insulator
Lab p. 41-44
Concepts-
1. Energy Transformations (ex: shaking = Mechanical --> Heat and Sound)
2.Phase changes- properties of solids, liquids and gases (Molecules Point of View Notes) and the phase change graph
3. Heat vs. Temp.- know the definitions of each.
4. Temperature change (Final
temp - initial temp)
5. Heat capacity
(depends on Mass and Material made of)
6. Properties of conductors and insulators - see page 42 in lab manual.
Heat is On Webquest due 9/24
Quiz 2: Friday 9/19- MOVED TO MONDAY 9/22
- Roller Coaster lab
- Types and forms of Energy
- Energy Calculations- Potential energy only
- Energy Booklet
**YOU MAY USE YOUR ENERGY BOOKLETS ON THIS QUIZ! :) **
Quiz 1: Friday 9/12
- Roller Coaster lab
- Types and forms of Energy
- Energy Calculations- Potential energy only
- Energy Booklet
**YOU MAY USE YOUR ENERGY BOOKLETS ON THIS QUIZ! :) **
Quiz 1: Friday 9/12
- Click HERE for a copy of the lab safety agreement to study from
- Scientific Method (More practice problems can be found HERE)
- Intro to Energy: Potential Energy vs Kinetic Energy (Additional practice can be found HERE)
Standard 4: The Physical Setting
Energy.
There is energy in all living things, whether they are moving or standing
still.
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Energy is the ability to do work or cause change.
2 States of Energy: There are two states of energy that we can discern;
1- Kinetic Energy: Energy that is in motion or moving. Associated with moving objects. Kinetic energy depends on the velocity and mass of an object. - Mechanical energy is always Kinetic!
2- Potential Energy: Energy that is stored or is at rest. Associated mostly with objects that are motionless in one place, but being pulled on by the force of gravity. - Chemical energy is always potential!
5 Forms of Energy: There are five basic forms of energy that we can identify every day;
1 Thermal: Heat energy. The energy of moving atoms and electrons in matter.
2 Chemical: The stored energy found in the chemical bonds that holds matter together. Some chemicals have more potential energy than others. When molecules react with each other, the energy stored in them may be released. Cars use the chemical energy stored in gasoline. Your body uses the chemical energy stored in food.
3- Mechanical: The energy of motion. Anything that is in motion contains mechanical energy; Wind, sound, flowing water, a runner running, a car moving etc..
'
4- Nuclear: The energy stored in the nucleus of an atom. Once released, this energy is extremely powerful. Found in nuclear reactors and nuclear bombs. Also found in the reactions that produce sunlight.
5- Electromagnetic/Electric: The energy of light. Anything that is composed of light, i.e Radio waves, X-rays, Uv-light, Microwaves, Cosmic rays, visible light are all examples of electromagnetic energy. The energy of flowing electrons in a current. Used to power most of modern day technology. Is derived from conversions of mechanical, chemical, nuclear, thermal and electromagnetic energies.
Know the following:
Why would a bowling ball being dropped from five feet have more potential energy than a tennis ball at the same height?
Why does a ball eventually stop bouncing?
What is energy efficiency? What does something that is inefficient produce a lot of?
What types of direct energy conversions are there in striking a match?
Performance Indicator 4.2 - Heat, Temperature, and Phase Changes
4.2a Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature.
4.2b Heat can be transferred through matter by the collisions of atoms and/or molecules (conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of heat (convection).
4.2c During a phase change, heat energy is absorbed or released. Energy is absorbed when a solid changes to a liquid and when a liquid changes to a gas. Energy is released when a gas changes to a liquid and when a liquid changes to a solid.
4.2d Most substances expand when heated and contract when cooled. Water is an exception, expanding when changing to ice.
4.2e Temperature affects the solubility of some substances in water.
Heat and Temperature- heat capacity
Atoms and molecules are perpetually in motion. The greater the temperature, the greater the motion.
Temperature: measure of the average kinetic energy of each particle within an object.
Heat Transfer: Conduction, Convection and Radiation
Heat moves in predictable ways, flowing from warmer to cooler objects, until both reach the same temperature.
Most objects will expand when heated and contract when cooled. Water is an exception, expanding when changing to ice.
In chemical reactions, energy is transformed into or out of a system.
Light, electricity, or mechanical motion may be involved in such transfers, in addition to heat.
Performance Indicator 4.2 - Heat, Temperature, and Phase Changes
4.2a Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both reach the same temperature.
4.2b Heat can be transferred through matter by the collisions of atoms and/or molecules (conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of heat (convection).
4.2c During a phase change, heat energy is absorbed or released. Energy is absorbed when a solid changes to a liquid and when a liquid changes to a gas. Energy is released when a gas changes to a liquid and when a liquid changes to a solid.
4.2d Most substances expand when heated and contract when cooled. Water is an exception, expanding when changing to ice.
4.2e Temperature affects the solubility of some substances in water.
Heat and Temperature- heat capacity
Atoms and molecules are perpetually in motion. The greater the temperature, the greater the motion.
Temperature: measure of the average kinetic energy of each particle within an object.
- Three temperature scales include Fahrenheit, Celsius and Kelvin.
- Heat energy is the total energy of the particles that make up an object (affected by mass and temperature)
- Heat capacity: ability of an object to hold heat and is determined by its mass and the material it is made of.
- Temperature change = Final temperature – Initial Temperature
Heat Transfer: Conduction, Convection and Radiation
Heat moves in predictable ways, flowing from warmer to cooler objects, until both reach the same temperature.
- Heat is measured in calories.
- Temperature change = Final Temperature – Initial Temperature
- Heat can be transferred through matter by collision of atoms and/or molecules (conduction).
- Through an empty space or a vacuum, heat is transferred as electromagnetic waves (radiation).
- In
a liquid or gas, currents will facilitate the transfer of heat
(convection) due to density differences. Hot gases or liquids
will rise because less dense and cold gases or liquids will sink because more dense. - A conductor (usually high density, solids, metals) transfers heat well, whereas an insulator (usually low density) does not.
Most objects will expand when heated and contract when cooled. Water is an exception, expanding when changing to ice.
- When heated, molecules become excited, move faster, spread out (less dense) and the object expands (thermal expansion).
- When cooled, molecules move slower, come closer together (more dense) and the object contracts (shrinks)
In chemical reactions, energy is transformed into or out of a system.
Light, electricity, or mechanical motion may be involved in such transfers, in addition to heat.
- Energy cannot be created or destroyed, but only changed from one form to another. In the process, some energy is always converted to heat.
- As temperature increases, kinetic energy increases and the number of collisions increase. As more collisions occur, the rate of a chemical reaction will increase.
Links- Forms of Energy:
Tips on how to make your home more energy efficient
Sound and Hearing
Beat the Heat- NASA
Energy Quest
