Summer Research Program for Science Teachers

Wm. H. Maxwell H.S., Brooklyn

2000

Measuring Thermal Energy Transfer

KEY WORDS:  Thermal energy quotient, specific heat, temperature, Celsius degrees, Joule, kinetic energy, heat flow, mass, density

RATIONALE:   Global Warming involves a transfer of heat around the world and an increase of the world's temperature overall; NASA spacecraft and instruments need to be designed by thermal engineers for safe travel into planetary orbit and beyond; "Spacecraft Blankets" are built for long-term durability and high thermal requirements to keep the spacecraft at room temperature (e.g.Cassini Project ~ NASA). This experiment is designed to show students the relevance of science investigations to "real-life" situations and give them a way to calculate and quantify heat transfer.

TEXT:  Different materials need different amounts of heat to produce similar changes in their temperatures. Materials have different specific heats. The specific heat of a material is the amount of energy it takes to raise the temperature of one kilogram of the material one degree Celsius. [9-12 Content Standard B- Properties of matter] Specific heat is measured in joules per kilogram per degree Celsius (J/kg X degrees C). Jumping into a cold pool can take your breath away on a hot day because the water can take heat away from your body more quickly because its specific heat is much higher than that of the air.

Specific heat can be used to measure changes in thermal energy by using the equation:

Change in thermal energy = mass x Change in temperature x specific heat

Q = m x delta T x Cp

MATERIALS: Calorimeter (bought or made from styrofoam cups with lid), metal samples like copper weight, lead sinker, and saved ball of aluminum from the students' lunches, thermometer in degrees C, cooking pot, boiling water, goggles, balance, graduated cylinder, hot plate, tongs [Teaching Standard D- Make accessible science tools]

PROCEDURE:

1) boil water in a pot on a hot plate
2) use a balance to find the mass of each sample & record in kg
3) add samples of copper, lead, & an aluminum ball into the boiling
water
4) two teams of students will test the same sample
5) read the initial temperature ( ti ) of 200 ml of water in the
calorimeter & record
6) carefully place the hot sample from the boiling pot into the
calorimeter and immediately record temperature changes every
few seconds until temperature is stable
7) record the final temperature in the tf box

8) use equation tofind the change in thermal energy
[Content Standard Unifying Concepts- Change, constancy, and measurement]

SPECIFIC HEAT CHART: (needed information)

 COMMON MATERIALS SPECIFIC HEAT (J/kg x oC) Water.............................................…. 4190 Iron..........................................… 450 Alcohol............................................….2450 Copper........................................ 380 Aluminum............................................ 920 Silver.......................................… 235 Carbon (graphite)............................... 710 Clay.........................................… 130 Sand..................................................….664

STUDENT DATA CHART:

 LAB GROUPS FINAL TEMP ( Tf ) INITIAL TEMP ( Ti) MASS (Kg) SPECIFIC HEAT ( Cp ) Q = JOULES 1. 2. 3. 4. 5. 6.

STUDENT LAB CONCLUSIONS:

1._________________________________________________________________________________________

2._________________________________________________________________________________________

3._________________________________________________________________________________________

RESOURCES:
Cassini Project ~ http://www.jpl.nasa.gov/cassini
Sierra Club's Global Warming Campaign ~ http://www.toowarm.org/
Individual Contribution to Global Warming ~ http://host.envirolink.org/edf/dosomething/whatcanwedo/
National Oceanic and Atmospheric Administration ~ http://www.noaa.gov/

[Teaching Standard D- Make accessible science media]