Description:

Students conduct an experiment to find out how well different wires radiate heat when voltage is applied across the wire. Students will use the results of their experiments to consider how the gauge of the wire and the type of wire affect the amount of heat radiated. Then, students will use what they learned from the experiment to make generalized inferences from their observations, and apply their understanding to an everyday situation.

This task is designed to take students approximately 40-50 minutes to complete. The activity portion is done in small groups. The follow-up questions are completed individually by each student working alone.

Overall Task Content Area:

Physical Science

Specific Knowledge Areas:

Interactions of energy matter

Performance Expectations:

• conducting investigations
• using equipment
• gathering, organizing, and representing data
• formulating conclusions from investigational data
• applying scientific principles to develop explanations and solve new problems

National Science Education Standards:

12 B PS 4: Motions and forces: Grades 9-12
4.3 The electric force is a universal force that exists between any two charged objects. Opposite charges attract while like charges repel. The strength of the force is proportional to the charges, and, as with gravitation, inversely proportional to the square of the distance between them.

12 B PS 5: Conservation of energy and increase in disorder: Grades 9-12
5.3 Heat consists of random motion and the vibrations of atoms, molecules, and ions. The higher the temperature, the greater the atomic or molecular motion.

12 B PS 6: Interactions of energy and matter: Grades 9-12
6.4 In some materials, such as metals, electrons flow easily, whereas in insulating materials such as glass they can hardly flow at all. Semiconducting materials have intermediate behavior. At low temperatures some materials become superconductors and offer no resistance to the flow of electrons.

12 A SI 1: Ability to do scientific inquiry: Grades 9-12
1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.

12 E ST 1: Abilities of technological design: Grades 9-12
1.2 Propose designs and choose between alternative solutions. Students should demonstrate thoughtful planning for a piece of technology or technique. Students should be introduced to the roles of models and simulations in these processes.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

National Council of Teachers of Mathematics:

NO3: Compute fluently and make reasonable estimates:
Grades 9-12 n. develop fluency in operations with real numbers, vectors, and matrices, using mental computation or paper-and-pencil calculations for simple cases and technology for more-complicated cases
Grades 9-12 o. judge the reasonableness of numerical computations and their results

MEAS1: Understand measurable attributes of objects and the units, systems, and processes of measurement:
Grades 9-12 m. make decisions about units and scales that are appropriate for problem situations involving measurement

PS2: Solve problems that arise in mathematics and in other contexts:
Grades 9-12

COM4: Use the language of mathematics to express mathematical ideas precisely:
Grades 9-12

REP1: Create and use representations to organize, record, and communicate mathematical ideas:
Grades 9-12

REP3: Use representations to model and interpret physical, social, and mathematical phenomena:
Grades 9-12

General Instructions to the Teacher:

This task is designed to take students approximately 40-50 minutes to complete.

Students will be working in groups of 4-6 for the experiment/activity part of this exercise. Each student must record the information in his or her own booklet (test papers). Allow from 20 to 25 minutes to complete the group work, and a similar time period for students to do their individual answers to the test questions.

Students should be ready to work as soon as the period begins. Group assignments should be made in advance. The materials should be set out at each lab station, if possible. A central supply area, if needed, should be accessible. All supplies should be clearly labeled.

Materials for Electrical Energy:

At this station students should have:

6-volt lantern battery
6 alligator clips
knife switch
crayon
4 wires, labeled (32-gauge copper, 36-gauge copper, 32-gauge steel, 32-gauge nichrome)
100 g mass
book
clock
string
scissors
paper towels
metric ruler
1 pen or pencil

Advance Preparation:

You may want to ask students to bring their watches to class on the day of the exercise.

Please cover the safety concerns of shocks, short circuits, and burns to all students before beginning this activity. Also, advise students that the wires will become hot once the circuit is closed. Students should NOT handle the wires directly until they have had a chance to adequately cool. During the experiment, the circuit should be completed using the knife switch ONLY.

Safety:

• Be careful.
• Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.