Where There's Light, There's Hot Food!!!

Jan 30 2012

Source: geraldine

Summary Information

Keywords:

Energy, Law of Conservation of Energy, Light, Reflection of Light, Angles of Incidence, Solar Energy, Distribution of Energy, solar Ovens

Topic:

Algebra

Earth Science

Physical Science

Physics

Target Grade (Ages):

Grade 9 (Ages 14-15)

Grade 10 (Ages 15-16)

Grade 11 (Ages 16-17)

Grade 12 (Ages 17-18)

Estimated Time Required:

8+ hours

Diversity Indicators:

This lesson is suitable for students in Grades 9-12 who are in a multi level classroom.

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LESSON

Goals and Prerequisites

Goals:

1. To enable the students to apply the concept of solar energy conservation.

2. To introduce the students to the concept of angles and its effect on the amount of light reflected.

3. To enable the students to design,construct, manipulate, critique, evaluate and revise the solar oven.

Prerequisites:

1. Knowledge of the Law of Conservation of Energy

2. Knowledge of the concept of energy transfer and the energy pyramid

3. Basic knowledge of angles

Instructional Objective(s)

At the end of the lesson, the students will be able to:

1. recall, discuss and explain the concepts of energy conservation

2. explain & discuss the concepts of angles, angle of incidence, and the reflection of light

3. design & construct a solar oven

4. demonstrate the use of the solar oven in conserving energy

5. citique,evaluate and revise the solar oven

Instructional Resources

Background:

For this lesson, a knowledge and understanding of the Law of Conservation of Energy and its application is important. The teacher might need to do a review of the kinds of energy and how the law applies to each kind of energy. A specific lesson of the definition of angles and angles of incidence is required to identify the angle of incidence and mathematically determine the effect of angles on the amount of light reflected. This is ncessary to determine the intensity of heat produced as the light energy or solar energy is converted. This part of the lesson requires coordination with the Math Department and will need handouts and activity sheets prior to the actual class. For activites on this lesson, the teacher could use the website, http://librarythinkquest.org.

Solar ovens or solar cookers work on the basic principle that sunlight is converted to heat energy and the retention of this converted energy into heat energy that is retained for cooking. The fuel that is used for this process is sunlight. The concept involves conversion of sunlight into heat energy, the retension of this converted energy and the capture extra sunlight to maintain the heat. For more information on solar ovens and solar cookers, go to http://solar cooker.org

Materials:

Video on the Law of Conservation of Energy in a Simple Pendulum(www.youtube.com/watch?v=51RCyBr_nGk -)

Experiments or worksheets on the topic of energy conservation from textbooks or the internet (optional)

Handouts or worksheets on angles of incidence (http://www.sasked.gov.sk.ca/docs/physics/u3b12phy.html,

Pictures of solar ovens

Data and information on solar ovens

Procedures for the construction of a solar oven

Rubrics and checklists for assessments (The teacher may use what is in this lesson plan, revise or make his or her own).

Procedure:

Part A: Do Now (Recall)

This part of the lesson will involve the students in answering an open ended question: What do you understand by the statement, "Energy cannot be created or destroyed, it could only be transformed".

1. The statement, "Energy cannot be created or destroyed, it could only be it could only be chnaged from one form to another" is written on top of a big POST IT paper.

2. The Post It paper is divided into four columns and labeled as below:

a. On top of the first column, write the word, AGREE. In the second column, write the word EVIDENCE to show why you agree. In the third column, write the word DISAGREE and in the fourth column, write the word EVIDENCE to show why you disagree.

Recall Activity Sheet

Question/ Topic

Agree

Evidence

Disagree

Evidence

b. The students write their evidences on Post It and discuss this in class as they are called. This could count as an assessment for participation.

c. The students stick the Post Its on the Recall Activity Sheet after the activity.

3. Recall the concept of energy and its conservation using the video

(www.youtube.com/watch?v=51RCyBr_nGk) PLEASE ATTACH VIDEO

Part B: Constructing the Solar Oven

Task: To build a solar cooker so we can cook foods for a class picnic

Requirements:

You may work in a team of 2-3; teams will document which partner contributes what part of the project

Part C: Making the Design

1. Study solar cooker designs. The following websites are recommended:

a. http://www.wisementrading.com/solarcooking.htm has commercial designs with good pictures

b. http://solarcooking.org has lots of designs and pictures

c. http://members.tripod.com/~ashokk_3/solar1.htm has a lot of good pictures (and probably a lot more information than you want), but its great for inspiration

d. http://www.backwoodshome.com/articles/radabaugh30.html has a design with very specific

directions

2. Read the handout on the Principles of Solar Cooker Designs (http://solarcooking.org/sbcdes.htm) to get more understanding of what a box solar oven is and what makes a solar cooker successful.

2. Choose and draw the design of your chosen Box Solar Oven:

a. Attach a printout or sketch of your design.

b. Fill in the information below:

Our design is from ________________ (Reference)

This type of cooker is a _____________.

We chose this design because ________________.

c. Evaluate the design using the suggested checklist in thelesson plan.

Part D: Constructing the Solar Oven:

1. Discuss the procedures for the construction of a basic solar oven.(http://www.ehow.com/how_6232133_make-basic-solar-cooker.html)

2. Construct the prototype of the basic solar oven piece by piece with the students.

3. Evaluate the prototype solar oven using a project rubric. (see attached)

4. Reconstruct the prototype to correct any deficiencies.

Part E: Testing the Functionability & Efficiency of the Solar Oven

1. To test the functionability and efficience of the basic solar oven, the students perform the following:

a. Each student will be given 480 mL of water (2 cups).

b. This will be warmed up in the solar cooker to see how long it will take for the water to get 10degrees warmer and at what temperature the water will have after 40 minutes.

2. Fill in the needed information below:

a. Starting temperature of water ______

b. Temperature of water after 40 minutes ______

c. Temperature rise in 40 minutes __________

d. Time to warm 480 mL of water by 10 °C ______

3. Complete teh follwoing to collect data on the funcitonability and efficiency of the constructed solar oven.

COOKER CALCULATIONS

How much of the Sun's energy did you capture in your cooker? These calculations will tell the tale!

PART 1: Measurements

The diameter of the top of your beaker (in cm) = _________
Mentally divide your aluminum solar panels up into rectangles and circles. For each part, measure its length and width (in cm) or diameter (in cm).
The temperature rose from _________ °C to __________ °C.
We started heating at ___________ and ended at __________ (time).

PART 2: Hypothesis

How efficient do you think your cooker is? That is, what percentage (%) of the sunlight hitting the cooker do you think was actually used to warm up the water inside the beaker?

Calculations:

(A) The Solar Panels

The area of the top of the beaker = pr2 = _______________ cm2.
The area of each rectangle (length x width) or circle (in cm2) =
The total area of solar panels = __________ cm2.
Our solar panels provided (area of panels/area of beaker) _______________ times more area of sunlight than the beaker alone.

(B) Heat Energy

The change in temperature of water in beaker = __________ °C
The heat energy to warm the water = (1 cal/°C.g) x (480 g water) x (change in temperature) = _________ calories
The time the water was heated = ____________ minutes
The total solar energy reaching cooker = (0.3cal/min.cm2)x(total area of solar panels) x (time in minutes) = ____________ calories
Our cooker was (heat energy to warm the water/solar energy reaching cooker)x100 = ___________% efficient.

Part E: Presentation and Discussion

The students will present their project to a Panel of Science teachers, two students and the Principal or the AP.

Extensions

1. Students will contruct a basic solar oven using the resulting data of their calculations to make a more efficient basic solar oven.

2. Students will compare the effect of artifical lights on the efficiency of a basic solar oven.

3. Students will cmpare the efficiency of the basic solar oven with one other design.

Assessments and Rubrics

RUBRIC:

A = 13-16 pts. and nothing below "3"; B = 10-12 pts and nothing below "2"; C = 7-9 pts; D = 5-6 pts; F = 0-4 pts.

	DOES NOT MEET STANDARDS (1)	PARTIALLY MEETS STANDARD (2)	FULLY MEETS STANDARD (3)	EXCEEDS STANDARD (4)
construction & design	The cooker's design and construction show little or no evidence of a valid design or careful workmanship.	The cooker has a valid design, but there is either use of non-allowed materials o sloppy workmanship.	The cooker is made to a valid design. It is made of the accepted materials. The workmanship is clean and shows pride in the cooker.	The cooker makes use of a difficult design (such as a parabolic cooker) or an original design. Or the cooker makes innovative use of materials.
performance	The solar cooker does not raise the temperature of water at all.	The cooker raises the temperature of 480 mL of water, but by less than 10 °C.	The cooker raises the temperature of 480 mL of water by at least 10 °C.	The cooker wins the class competition or has a performance equal to the top 10% of all cookers in the freshmen class.
procedures	The procedures are significantly incomplete. There is little or no evidence that the team understands this standard.	Some procedures are incomplete but some show quality work. There is evidence that the team understands what it means to write a procedure With a few questions to the team, another group could build a similar cooker.	All portions of the procedures are complete. Another team could build a similar cooker and compare results based solely on the procedures	The procedures show a meticulous attention to detail and in-depth, thoughtful reflection on the construction and performance of the cooker.
work habits	The team was dysfunctional: members needed a significant amount of outside prompting to stay on task, and there was little sense of shared responsibility.	An attempt was made to stay on task and divide up the work equitably, but poor work habits effected the team's ability to do the work efficiently or independently.	Team members stayed on task and divided up the work equitably.	The team made positive use of members' different talents. The team provided leadership or assistance to others in the class or in general added to the positive working atmosphere of the class.

2. Design Checklist: 4 3 2 1

Specifications:

Suitability of Materials

Correct Measurements

Units of Measure

Creativity of Design

Resourcefulness

External Resources

http://homepage.mac.com/sklemmer/Essentials%20I/solaroven.htm#logs

http://solarcooking.org/sbcdes.htm)

http://www.ehow.com/how_6232133_make-basic-solar-cooker.html)

Math Department

www.youtube.com/watch?v=51RCyBr_nGk

Credits

Geraldine V de Leon, Forsyth Satellite Academy (Author) Dominador "Jun" Caoile (Math Consultant and Teacher)

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