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".
- 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.
- The Post It paper is divided into four columns and labeled as below:
- 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
- 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.
- The students stick the Post Its on the Recall Activity Sheet after the activity.
- Recall the concept of energy and its conservation using the video
Part B: Constructing the Solar Oven
Task: To build a solar cooker so we can cook foods for a class picnic
- 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
- Study solar cooker designs. The following websites are recommended:
- http://www.wisementrading.com/solarcooking.htm has commercial designs with good pictures
- http://solarcooking.org has lots of designs and pictures
- 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
- http://www.backwoodshome.com/articles/radabaugh30.html has a design with very specific directions
- 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.
- Choose and draw the design of your chosen Box Solar Oven:
- Attach a printout or sketch of your design.
- Fill in the information below:
Our design is from ________________ (Reference)
This type of cooker is a _____________.
We chose this design because ________________.
- Evaluate the design using the suggested checklist in the lesson plan.
Part D: Constructing the Solar Oven:
- Discuss the procedures for the construction of a basic solar oven.(http://www.ehow.com/how_6232133_make-basic-solar-cooker.html)
- Construct the prototype of the basic solar oven piece by piece with the students.
- Evaluate the prototype solar oven using a project rubric. (see attached)
- Reconstruct the prototype to correct any deficiencies.
Part E: Testing the Functionability & Efficiency of the Solar Oven
- To test the functionability and efficience of the basic solar oven, the students perform the following:
- Each student will be given 480 mL of water (2 cups).
- 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.
- Fill in the needed information below:
- Starting temperature of water ______
- Temperature of water after 40 minutes ______
- Temperature rise in 40 minutes __________
- Time to warm 480 mL of water by 10 °C ______
- Complete teh follwoing to collect data on the funcitonability and efficiency of the constructed solar oven.
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?
(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.