Download conduction (kuhn-DUHK-shuhn): process of heat transfer in solids

Quiz 2 Study List - 6th Grade Science – Miss Fox
Scientific Method: is a series of steps used to investigate a problem
 Purpose: is the reason for the experiment
 Hypothesis: is an educated guess
 Materials: is the list of supplies needed for the experiment
 Experiment/procedures: are the step by step instructions to conduct the investigation
o Variable: any factor that can be changed in an experiment
 Analysis: is the organization of the collected data in to graphs and explanations
 Conclusion: at the end of a scientific investigation a conclusion interprets the results. It is the claim,
evidence and reasoning summary of what resulted. Was your Hypothesis correct?
Math Skills:
 Graphs
o Pie chart
o Line graph
 Calculate density
o Density = Mass divided by volume
 Mean (average), median and mode
o Example: Find the mean, median, and mode for the following list of values:
 13, 18, 13, 14, 13, 16, 14, 21, 13
o The mean is the usual average, so:
 (13 + 18 + 13 + 14 + 13 + 16 + 14 + 21 + 13) ÷ 9 = 15
o The median is the middle value, so I'll have to rewrite the list in order:
 13, 13, 13, 13, 14, 14, 16, 18, 21
 There are nine numbers in the list, so the middle one will be the (9 + 1) ÷ 2 = 10 ÷ 2 =
5th number:
 13, 13, 13, 13, 14, 14, 16, 18, 21
 So the median is 14. Copyright © Elizabeth 2006-2008 All Rights Reserved
o The mode is the number that is repeated more often than any other
 So 13 is the mode.
Weather: day-to-day conditions of the atmosphere
Climate: average weather conditions of an area over many years
Meteorology: is the scientific study of weather.
Meteorologist: is a person who studies the cause and effects of Earth's weather.
Weather tools – be prepared to describe how to use each of the following weather tools and what they
measure.
 Thermometer – measures temperature
 Compass – is used to determine the direction from which the wind is coming.
 Anemometer – measures wind speed
 Hygrometer – measures humidity
 Barometer – measure air pressure
Properties/characteristics of air
 Air: is a mixture of gases in Earth’s atmosphere. Air is composed mostly of nitrogen (78%) and
oxygen (21%).
 Air is a colorless, tasteless, odorless mixture of gases.
 A major source of oxygen in Earths atmosphere comes from plants.
 Three physical states of water in the atmosphere – solid, liquid and gas/water vapor.
 The atmosphere/air also contains small particles of dust, volcanic ash, sea salt and dirt.
 Matter: anything that has mass and volume (takes up space) – air which is a mixture of gases is
matter.
Atmosphere: envelope of gases that surrounds the Earth
 Thermosphere – Farthest layer from the earth, has fewer gas molecules, very hot, has the ionosphere
(home of the auroras - electrically charged particles)
 Mesosphere – Coldest layer, temperature decreases as altitude increases
 Stratosphere – Layered gases, including the ozone layer which protects life on earth from ultraviolet
rays from the sun
 Troposphere – Closest layer to the earth, contains almost 90% of the atmosphere’s molecules
Differences in atmospheric temperature at different altitudes is caused mainly by the way gases absorb
solar energy. Some gases absorb the sun’s energy better than others.
Atmospheric temperature:
 Decreases in the troposphere
 Rises in the stratosphere
 Decreases in the mesosphere
 Increases in the thermosphere
Altitude : height above sea level
Air pressure: the measure of the force with which air molecules push on a surface
Air Pressure is affected by altitude and temperature.
Air Pressure:
 Is greatest at the earth’s surface, the troposphere, because gravity pulls gas molecules
downward
 Is the least in the thermosphere because the gas molecules are further apart (we also call this
“thin air”)
 Is greater during colder weather due to the increased density of the gas molecules
 Is less during warmer weather due to the decreased density of the gas molecules
 When high pressure and low pressure meet, it causes wind.
Kinetic energy: energy of motion.
Heat: energy of particles moving from warmer regions to cooler regions
• Heat is not a substance, but a form of energy.
• Heat is the total kinetic energy of all the particles in a sample of matter.
• Heat energy moves from a warmer object to a cooler object.
Thermal energy is always transferred from warmer to cooler areas.
Solar energy: is when energy rays from the sun pass through Earths atmosphere.
Vacuum: region where no matter exists.
Radiation: is energy that transfers as waves or rays through space between objects and materials.
Radiation is the transfer of energy as electromagnetic waves like from the sun or from a light bulb.
Radiant energy: energy given off by the Sun that can travel through empty space
• The Sun gives off radiant energy that travels through space by radiation.
• Energy from the Sun is transferred through a vacuum to Earth by radiation.
• When light energy from the Sun is absorbed by matter, it is changed into heat energy.
• Earth’s surface changes light energy from the Sun into heat energy.
• Only a small part of the Sun’s energy reaches Earth’s surface; the rest is absorbed by the atmosphere
or reflected back into space.
Electromagnetic energy (wave) is a form of energy that can travel through a vacuum.
Radiation from the sun goes to the following places:
 50% is absorbed by the earth’s surface
 25% is scattered and reflected by clouds and air
 20% is absorbed by ozone, clouds and atmospheric gases
 5% is reflected by the earth’s surface
Conduction: is the energy transfer between materials as a result of contact.
Thermal Conduction is transferring heat through a material like when a metal spoon gets hot from stirring
hot soup. Near the surface of the earth, air is heated by thermal conduction.
Conductor: substance that conducts heat easily
• Heat is transferred through solids by conduction.
• A conductor is a substance that allows heat to move through it easily.
• All metals are good conductors.
Radiation Balance occurs when there is a balance between the solar energy entering the earth’s atmosphere
and the amount of thermal radiation leaving the earth’s atmosphere and returning to space.
The greenhouse effect is the warming of the surface and lower atmosphere of the earth that occurs when
carbon dioxide (CO2), water vapor, and other gases in the atmosphere absorb and trap and reradiate thermal
energy back to the earth.
Density: is the amount of matter in a volume of material. Density is a property of matter. All matter has
density, including all solids, liquids and gases. If you compare equal volumes of matter, and one is heavier
(has more mass), the heavier volume is denser.

Formula for Density = Mass /volume
Convection: process of heat transfer in gases and liquids
Convection is the transfer of thermal energy by the circulation or movement of a liquid or a gas. Boiling
water is an example of convection.
Convection current: movement of gases or liquids caused by differences in density
Convection Currents occur when warm air or water rises (becomes less dense) and cool air or water sinks
(becomes more dense).
• The transfer of heat in gases and liquids is called convection.
• Convection currents are movements of gases or liquids caused by differences in density.
• Convection currents can transfer heat.
• Convection currents cause the movement of air above Earth’s surface and the movement of large
sections of Earth’s crust.