The Solar Cooker: Introduction to Alternative Energy Scientific Theme(s): Physical Science *Energy Transfer and Transformations Grade Level(s): * 3-­‐5 * 6-­‐8 Lesson Duration: 3 lessons, each 60 minutes long Overview Students will learn that the sun is an energy source in the form of heat and light. They will directly observe an example of how the heat can be captured and used for cooking, through making S’mores in a solar cooker. Objectives Students will: 1. Attain knowledge of the sun as an energy source. 2. Document temperature data. 3. Graph data in a line graph chart. 4. Formulate a hypothesis and test it. 5. Eat S’mores they cooked in their homemade solar cooker. Grade Level Expectations (GLEs) Addressed Science as Inquiry and Process [3] SA1.1 asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring, and communicating Physical Science [3] SB3.1 recognizing that temperature changes cause changes in phases of substances Required Background 1. Information on the most common energy sources we use (solar, wind, hydro, biomass, nuclear, chemical, electrical, fossil fuels, geothermal), specifically solar energy. 2. The scientific method (making a hypothesis/prediction, observing, gathering data, making conclusions). 3. Knowledge of how to record data and create a line graph. Vocabulary Solar Energy Graphing: X-­‐axis, Y-­‐axis, line graph, scale Degrees Fahrenheit Scientific Hypothesis Scientific Simulation Base Temperature Data Table Variables Materials Solar Cooker • A sunny day (temperature above 60F) OR shop lamps to simulate the sun • Pizza boxes (either 1 per student, or 1 per group) • Black construction paper (1 sheet per pizza box) • Aluminum foil (1 roll per group, or have students share a few rolls) • Plastic wrap (1 roll per group, or have students share a few rolls) • Glue (1 per group or student) • Tape (1 per group or student) • Rulers (1 per student) • Pen or pencil (1 per student) • Scissors (1 per student or per group) • Thermometers (1 per pizza box) • Clock (1 for the classroom) • Data recording sheet (1 per group or student) • Additional adult helpers as needed S’Mores
• Graham crackers (1 per student) • Mini marshmallows (1 per student) • Chocolate (little chunk per student) Graphing
• Science Journal (1 per student) • Graph worksheet (1 per student) • Rulers (1 per student) • Pencils (1 per student) • Colored markers (one color per student) Activity Preparation and Procedure *Throughout lessons keep a running list of vocabulary words and concepts on white board or poster board.* Part I: Introduction & Building the Solar Cooker (45-­60 minutes) 1. Introduce solar energy: “Sunlight is pure energy. The sun is the original energy source. Nearly all other sources of energy originally got their energy from the sun. Plants convert solar energy into leaves, flowers and fruits. Animals, which eat plants, convert the energy into body mass. When animals die, their energy is decomposed and over extensive time, becomes stored as oil, coal or natural gas. Sunlight also provides energy in the form of heat and light for humans, animals and plants.” 2. Ask students to decide, since sunlight provides us with heat, do they think we can use it to cook? Divide up classroom in ‘yes’ and ‘no’ camps by having student get up and stand on opposite sides of the classroom. • Ask the ‘yes’ camp how they think we can cook with it (i.e. do we need materials). • Ask the ‘no’ camp, why they don’t think it is possible (i.e. is it not hot enough, do we not have the technology to harness it). 3. Have students make a hypothesis and predictions and write them in their science journal: a. Will we be able to cook S’mores with solar energy? b. How hot do they think it will get inside the solar cooker? (prior to this have students measure the temperature in the classroom with their thermometers to have a temperature reference point – will it be hotter or colder inside the solar cooker?) c. How long do they think it will take to cook the s’mores in the solar cooker? 4. Divide students into groups or have each student make their own solar cooker. Divide out materials. If possible, show students an example of a solar cooker, like the one they will build. a. On the top flap of the pizza box, draw a square with a marker with edges spaced 1-­‐2” from the four sides of the box. b. Cut along three lines of the box on the sides and front edges of the box. Leave the fourth line uncut. Fold back the top of the box at the fourth line. c. Cut aluminum foil to fit on the inside of the lid and to line the inside of the box including the sides. Glue foil into place. d. Tape plastic wrap to the underside of the cut opening on the top of the box. The plastic should be tightly sealed as to not let any air in. This will be the window. e. Glue black construction paper to the bottom of the inside of the box on top of the foil. f. Place thermometers inside the boxes so they are visible from the window. g. Have students write their names on the pizza boxes to identify them. Part II: Making S’mores and Recording Data (60 minutes) 1. Review information on solar energy and solar cookers from previous class. 2. Hand out data logging sheets, to record time and temperature and have students record the start time and the base temperature inside the cooker. 3. Distribute graham crackers, marshmallows, and chocolate to each of the students and have them be placed inside the solar cooker. Make sure all of the S’mores fit under the “window” of the cooker (5-­‐6 per cooker). 4. Take solar cooker outside and place them in an area of direct sunlight, with no shade or other obstruction. If the weather does not permit this, use shop lamps indoors to simulate sunlight. 5. Close the oven lid. Have students prop open the lid to the window with a ruler, pen, straw or other device of their choosing. The foil inside the lid should be directly facing the heat source. The lid should ideally not be opened anymore until the S’mores are done. 6. Every 10 minutes ask the students to record the temperature and the time on their data logging sheets. Continue doing this until the S’mores are done. 7. When the S’mores are done, have the students record the end time, and calculate how long it took to cook their S’mores. This may vary by solar cookers, as well as the temperature each solar cooker reached. 8. Eat S’mores and enjoy! Part III: Graphing Data & Wrap-­up (45-­50 minutes) 1. Review key words and concepts from the previous two classes. 2. Hand out graphing worksheets. 3. Have students take out their data logging sheets. 4. Explain elements of a line graph to students on overhead or white board; line graph, x-­‐axis, y-­‐axis, scale, title of graph. 5. Show an example of how to graph points (time-­‐temperature) and create a graph either as a whole class or have students do it in their groups, or on their own if they had individual solar cookers. 6. After the line graph is made, check them for accuracy and if they are correct students can use colored markers to reinforce the data points and the line connecting the points. 7. Ask students to write in their journals the steps to creating a line graph, the way they just did it on the graphing worksheet, explaining the process of creating a graph 8. Wrap-­‐up a. Students can review their hypothesis and predictions made at the beginning of this unit and share it with the class. Then ask students to report to the class how long it took them to cook their S’mores and the highest temperatures recorded as they recorded in their graph or data logging worksheet. b. Ask them why they think not every solar cooker produced the same data, talk about variables that may have existed and how they can influence an experiment. c.
Have students think about what other food items could be cooker in a solar cooker and if any of the variables would need to be modified for different foods (i.e. solar cooker size, cooking time, number of foil collectors, temperature requirements) Assessment 1. Students should be able to write the steps to creating a line graph. 2. Students should be able to verbally explain the principles of cooking with solar energy (heat transfer, building a collector, what the role of aluminum foil and black poster board is in the cooker, the need for direct sunlight and modifications if other foods were to be cooked). Complementary Activities and Extension Ideas 1. Students could each build a solar cooker with different variables: a. sizes of cardboard boxes, b. numbers of lids wrapped in foil (could be up to 4) – solar collectors c. number of S’mores inside the cooker d. angle of lid being propped open e. placing only foil or only black poster board on the inside of the cooker 2. Observe and record differences in temperature and cooking time as it relates to the solar cooker variables. References New Mexico Solar Energy Association. Make a Pizza Box Solar Oven. Retrieved from http://www.nmsea.org/Curriculum/4_6/pizza_box_oven/pizza_box_ovens.htm Home Science Tools. (2014). Build a Solar Oven. Retrieved from http://www.hometrainingtools.com/build-­‐a-­‐solar-­‐oven-­‐project/a/1237/ Bellinghieri, Cathy and Gonzalez, Leslie. The Education Fund. Solar Energy Fun Powered by the Sun. Retrieved from https://www.educationfund.org/uploads/docs/Publications/Curriculum_Ideas_Packets/2010-­‐ 11%20Curriculum%20Packets/Solar%20Energy%20Fun%20Powered%20by%20the%20Sun.pdf Solar Cooker Graph
SOLAR COOKER DATA
Start time:______________________ End time:_____________________ Total cooking time: _________________________________ Time Temperature Example: 11:00 am 60F