Light vs. Heat Bulbs
Students explore the efficiency of light bulbsCopyright Free Clipart Now http://www.freeclipartnow.com/
Students measure the light output and temperature (as a measure of heat output) for three types of light bulbs to identify why some light bulbs are more efficient (more light with less energy) than others.
Substituting energy-efficient light bulbs is one way to reduce energy consumption. Lighting needs are still provided, but with less energy use. Engineers are developing many new types of light bulbs. CFLs are becoming commonplace, but we can expect new and improved ones soon.
After this activity, students should be able to:
- Calculate energy use and analyze how changing their behaviors and appliances impacts the amount of energy they use.
- Conduct an experiment and make comparisons based on experimental evidence.
CCSS.Math.Content.6.NS.B.3 Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation.
Grade 6
Do you agree with this alignment?CCSS.Math.Content.6.RP.A.3c Find a percent of a quantity as a rate per 100 (e.g., 30% of a quantity means 30/100 times the quantity); solve problems involving finding the whole, given a part and the percent.
Grade 6
Do you agree with this alignment?CCSS.Math.Content.7.EE.B.3 Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies.
Grade 7
Do you agree with this alignment?
Energy is the capacity to do work.
Grades 6-8
Do you agree with this alignment?STEL-1M Apply creative problem-solving strategies to the improvement of existing devices or processes or the development of new approaches.
Grades 6-8
Do you agree with this alignment?
recognize and apply mathematics in contexts outside of mathematics
Grades -1-12
Do you agree with this alignment?use observations about differences between two or more samples to make conjectures about the populations from which the samples were taken
Grades 6-8
Do you agree with this alignment?select and apply techniques and tools to accurately find length, area, volume, and angle measures to appropriate levels of precision
Grades 6-8
Do you agree with this alignment?model and solve contextual problems using various representations, such as graphs, tables, and equations
Grades 6-8
Do you agree with this alignment?select appropriate methods and tools for computing with fractions and decimals from among mental computation, estimation, calculators, or computers, and paper and pencil, depending on the situation, and apply the selected methods
Grades 6-8
Do you agree with this alignment?work flexibly with fractions, decimals, and percents to solve problems
Grades 6-8
Do you agree with this alignment?understand and use ratios and proportions to represent quantitative relationships
Grades 6-8
Do you agree with this alignment?understand relationships among units and convert from one unit to another within the same system
Grades 6-8
Do you agree with this alignment?understand both metric and customary systems of measurement
Grades 6-8
Do you agree with this alignment?
Energy is a property of many substances and is associated with heat, light, electricity, mechanical motion, sound, nuclei, and the nature of a chemical. Energy is transferred in many ways.
Grades 5-8
Do you agree with this alignment?Science influences society through its knowledge and world view. Scientific knowledge and the procedures used by scientists influence the way many individuals in society think about themselves, others, and the environment. The effect of science on society is neither entirely beneficial nor entirely detrimental.
Grades 5-8
Do you agree with this alignment?Develop descriptions, explanations, predictions, and models using evidence. Students should base their explanation on what they observed, and as they develop cognitive skills, they should be able to differentiate explanation from description--providing causes for effects and establishing relationships based on evidence and logical argument. This standard requires a subject matter knowledge base so the students can effectively conduct investigations, because developing explanations establishes connections between the content of science and the contexts within which students develop new knowledge.
Grades 5-8
Do you agree with this alignment?Mathematics is important in all aspects of scientific inquiry.
Grades 5-8
Do you agree with this alignment?Electrical circuits provide a means of transferring electrical energy when heat, light, sound, and chemical changes are produced.
Grades 5-8
Do you agree with this alignment?Think critically and logically to make the relationships between evidence and explanations. Thinking critically about evidence includes deciding what evidence should be used and accounting for anomalous data. Specifically, students should be able to review data from a simple experiment, summarize the data, and form a logical argument about the cause-and-effect relationships in the experiment. Students should begin to state some explanations in terms of the relationship between two or more variables.
Grades 5-8
Do you agree with this alignment?Communicate scientific procedures and explanations. With practice, students should become competent at communicating experimental methods, following instructions, describing observations, summarizing the results of other groups, and telling other students about investigations and explanations.
Grades 5-8
Do you agree with this alignment?Use mathematics in all aspects of scientific inquiry. Mathematics is essential to asking and answering questions about the natural world. Mathematics can be used to ask questions; to gather, organize, and present data; and to structure convincing explanations.
Grades 5-8
Do you agree with this alignment?Technology influences society through its products and processes. Technology influences the quality of life and the ways people act and interact. Technological changes are often accompanied by social, political, and economic changes that can be beneficial or detrimental to individuals and to society. Social needs, attitudes, and values influence the direction of technological development.
Grades 5-8
Do you agree with this alignment?
6.NS.3 Fluently add, subtract, multiply, and divide multi-digit decimals using the standard algorithm for each operation.
Grade 6
Do you agree with this alignment?6.RP.3.c Find a percent of a quantity as a rate per 100 (e.g., 30% of a quantity means 30/100 times the quantity); solve problems involving finding the whole, given a part and the percent.
Grade 6
Do you agree with this alignment?7.EE.3 Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies.
Grade 7
Do you agree with this alignment?
MS-PS3-4 Plan and conduct an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the temperature of the sample of matter.
Grades 6-8
Do you agree with this alignment?
MS-PS3-4 Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.
Grades 6-8
This resource focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices- Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.Do you agree with this alignment?
- Science knowledge is based upon logical and conceptual connections between evidence and explanations.Do you agree with this alignment?
Disciplinary Core Ideas- Temperature is a measure of the average kinetic energy of particles of matter. The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter present.Do you agree with this alignment?
- The amount of energy transfer needed to change the temperature of a matter sample by a given amount depends on the nature of the matter, the size of the sample, and the environment.Do you agree with this alignment?
Crosscutting Concepts- Proportional relationships (e.g. speed as the ratio of distance traveled to time taken) among different types of quantities provide information about the magnitude of properties and processes.Do you agree with this alignment?
Do you agree with this alignment?- Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.
Each group needs:
- incandescent light bulb (60 watt) with light socket/plug
- compact fluorescent light bulb (CFL, 13 watt) with light socket/plug
- LED bulb with light socket/plug
- infrared (IR) thermometer (available at Radio Shack or similar stores)
- ruler
- Student Worksheet (PDF), one per student
- (optional) watt meter, to confirm power
To share with the entire class:
- light meter
Lighting accounts for 20-25% of all the electricity used in the U.S. On average, a household uses 5-10% of its energy for lighting. A commercial industry, on the other hand, consumes 20-30% of its energy in lighting only; 50% or more of the energy used is wasted by obsolete equipment, inadequate maintenance, or inefficient use. Energy savings for lighting will require either reduction in use or more efficient usage.
Recall the differences – conservation = turning off light bulbs, efficiency = using bulbs to produce light with less electricity). Today's activity focuses on efficiency.
Note that new technologies (developed by scientists and engineers!!!) can bring about substantial savings in energy use but still provide us with the benefits of electrical lighting. (Hold up various types of bulbs.) Do these look familiar? (Expect students to be familiar with incandescent and [hopefully] CFLs, but they may not have seen LED [light-emitting diode] bulbs.) LEDs are currently quite expensive, but we should see more of them in stores in the coming years.
- Divide the class into groups of three or four students each.
- Hand out the activity sheets and go over the procedure. (5 min)
- Provide the lux reading for each bulb.
- For Part II, it is better to work as a class or in very small groups (1-2 students). This can be started as they wait for the light bulbs to heat up.
- As a demo or extra station, introduce LED bulbs (light-emitting diode).
- Complete the data collection. Note: it is important that several readings of temperature be taken for each bulb from sides and top as significant variations in the temperature exist around the bulb. Have students choose a representative temperature, the maximum, or take several readings and calculate an average.
- Discuss reasons for increased efficiency – light – the desired energy "product", but also varying amounts of heat generated. . Remind students that in some cases heat is the desired product, such as waming lamps for food, or for incubation. However, light bulbs would ideally produce no heat. Also ask if this is possible? (Answer: No, entropy is always increased, there is no such thing as 100% efficiency)."
In a light bulb, electromagnetic energy (electricity) is converted into heat and light, which is also an electromagnetic form of energy. - Review conservation and efficiency ideas (perhaps using the classroom board) and spend a minute or two talking about the final project. Tell the class that they will need to define their ideas. Which applications suit the incandescent bulbs better? And which suit the CFL/LED bulbs better? Does it make sense in some instances to want both heat and light produced?
Worksheets: Collect and review student worksheet to assess their data collection, calculations and answers to discussion questions.
- The bulbs can get quite hot, especially the incandescent bulb, so warn students to not touch the bulbs.
- Warn students not to look at the bulbs for too long; they might strain their eyes.
Contributors
Jan DeWaters; Susan Powers; Clarkson and St. Lawrence University Students (K-12 Project Based Learning Partnership Program)
Supporting Program
Office of Educational Partnerships, Clarkson University, Potsdam, NY
Acknowledgements
This activity was developed under National Science Foundation grant nos. DUE 0428127 and DGE 0338216. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.
Copyright
2013 by Regents of the University of Colorado; original © 2008 Clarkson University