Energy and Matter

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ISCI 6501: Derrick Jones

Contents

Grade Level and GPS

  • SPS7. Students will relate transformations and flow of energy within a system.
c) Determine the heat capacity of a substance using mass, specific heat, and temperature.

Background Information

Specific heat capacity is the measure of heat energy required to increase the temperature of a unit quantity of a substance by a unit of degree. The reason that we say a unit of quantity is because there is a disagreement whether specific heat should be measured in regards to mass, number of atoms, or number of molecules (Specific Heat). The temperature of a matter is the direct measure of motion of the molecules found in the matter. This motion requires energy. Matter with higher energy will also have higher temperatures (Jones). In the physical science GPS, we choose to measure specific heat in regards to mass.

Specific heat is measured by units of Celsius. It can also be measured in units of Kelvin, but the standards would like us to Celsius. The amount of energy that takes to raise water’s temperature 1 degree Celsius is 4186 joules per kilogram. Joules are the derived unit of energy that is used by scientist. A joule is the amount of work done by a force of 1 Newton through a meter (Specific Heat).

Specific Heat Experiment.
Specific Heat Experiment.

These specific heat measures are used to determine the amount of energy that can be found in different materials. This is important because it helps us to understand what materials can hold certain amounts of energy (Jones).

Integration of Science Concepts

Students will be able to see how different materials have different specific heat measurement. Students will also be able to see that substances with higher specific heats will be able heat the water much quicker and to a higher temperature. It will help the students to understand the importance of lab safety as they will be working with boiling water.

Management Considerations

Be sure to remind your students to always wear safety goggles as they are working in the lab. Also, make sure that each student realizes that they are working with very hot materials. The materials may not look hot, but they are all could be hot. Tell the students to always be precautionary.

Common Misconceptions

  1. Energy is truly lost in many energy transformations.
  2. There is no relationship between matter and energy.
  3. If energy is conserved, why are we running out of it?
  4. Energy can be changed completely from one form to another (no energy losses).
  5. Things “use up” energy.
  6. Energy is confined to some particular origin, such as what we get from food or what the electric company sells.
  7. An object at rest has no energy.
  8. The only type of potential energy is gravitational.
  9. Gravitational potential energy depends only on the height of an object.
  10. Doubling the speed of a moving object doubles the kinetic energy.
  11. Energy is a “thing.” This is a fuzzy notion, probably because of the way we talk about newton-meters or joules. It is difficult to imagine an “amount” of an abstraction.
  12. The terms “energy” and “force” are interchangeable.
  13. From the non-scientific point of view, “work” is synonymous with “labor.” It is hard to convince someone that more “work” is probably being done playing football for one hour than studying an hour for a quiz.

Inquiry Lab Instructions

  1. Place water into a 600-mL beaker. Using a hot plate, bring the water in the beaker to a boil.
  2. Take each piece of metal substance and find the mass of each in units of grams.
  3. Take each metal substance and place it into a test tube. Then suspend the test tube in the the boiling hot water bath. Make sure that the test tubes are not completely submerged and make sure that the test tube is upright and the metal is not getting wet.
  4. Measure out 100.0 mL of distilled water and place the water into the calorimeter. Then, record the temperature of the water in the calorimeter. Remember 1 mL of water equals 1 gram.
  5. After the metal substances have been heating for 10 minutes, remove the test tubes with clamps or test tube holders from the water bath. Record the temperature of the boiling water as this is the temperature of the metal substance.
  6. Pour the metal substance from the test tube into the distilled water in the calorimeter. Use a stirring rod and stir the water. Place the top back on the calorimeter. Record the temperature when it reaches its highest point.
  7. Calculate the changes in temperature of the water ( Twater) and of the metal shot ( Tmetal). These are just simple subtractions. Remember, the water and metal had the same final temperature, but different initial temperatures. Also remember that T is never negative, so one calculation will be temperature final - temperature initial, and the other will be temperature initial - temperature final.
  8. Calculate the heat energy gained by the water. Use formula (1) from the introduction for this calculation.
  9. Remember that the heat gained by the water is equal to the heat lost by the metal, calculate the specific heat of the metal. This is simply rearranging formula (3) from the introduction to solve for the specific heat of the metal, and plugging-in your data. The specific heat of water is again, 1cal / g deg.C

Topic Related Annotated Resources

Lesson Related Resources

Resources

  1. Specific Heat Capacity. 2009. Retrieved from Wikipedia on September 26, 2009. http://en.wikipedia.org/wiki/specific_heat-capacity
  2. Jones, Larry (2009). Specific Heat. Retrieved September 26, 2009 from http://www.sciencebyjones.com/specific_heat1.htm
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