DescriptionUse this link to complete the assignment – https://docs.google.com/document/d/19f413xvX452A5LBxUYvgiqp_TQ-tKBtmNPs8PWsPWH0/edit
Although people all around the world use different sources of fuel to cook, everyone has a need for heating food in order to prepare meals. Electricity, Natural gas, and coal are three common fuel sources used for cooking in the United States. Some people do not have access to these fuel sources because of their location or cost. Solar ovens can provide a source of renewable cooking energy and they work very well in certain locations. In this project you will construct a solar oven and test your oven in various conditions in order to determine the best position for efficiently capturing energy from the sun in your geographic location.
Here is your goal for this lesson:
Understand how energy from the sun can be used in place of non-renewable energy sources.
Determine the most efficient way to position a solar oven where you live.
Pre-lab questions:
Visit ( http://profhorn.meteor.wisc.edu/wxwise/radiation/sunangle.html) to see how the amount of solar energy that reaches the surface of the earth changes based on latitude and season. What is the amount of solar energy in (Watts/m2) that hits the land at the north pole in March? What amount reaches the equator in March?
What is the main source of energy used for cooking in your home?
What is the main source of energy used by people in developing countries to cook food?
Research solar cookers and list 3 places (cities or countries) that are ideal for using solar ovens.
What is the independent variable in this experiment? What is the dependent variable? What are some of the controlled variables?
Read through the procedure below and write your hypothesis. Using your knowledge of your position on the Earth and the position of the sun, based on the season and your geographical location, make a prediction about which direction your solar over will need to face in order to capture the most heat. Remember to put your hypothesis in an “if/then format” that mentions the variables in the experiment.
These supplies are needed:
Cardboard box (a pizza box works very well for this experiment)
Aluminum foil
Plastic wrap
Tape
Thermometer (A food thermometer may be easiest to use)
A plastic ruler or piece of cardboard to hold the solar focusing flap in place.
Food to cook (Water can be used for simplicity, marshmallows are fun to cook, *Note* Do not attempt to cook raw foods for this experiment)
A paper plate or glass pie dish to hold the food in your oven.
A compass (to determine the direction for positioning your solar oven)
Procedure:
Oven construction
Use the instructions and pictures found here
( https://www.msichicago.org/fileadmin/assets/online_science/summer_brain_games/activity_PDFs/SBG12_Solar.pdfto help build your oven.)
Draw a square about two inches around the inside perimeter of the pizza box lid.
Cut out three sides of that square, leaving the side closest to where the box lid folds in place. This flap will serve to focus sunlight down into your oven.
Cover the inside bottom of your box in black paper or aluminum foil. Cover the flap that you created in aluminum foil with the shiny side facing out.
On the underside of the lid, tape plastic wrap over the opening to create a window into your oven. This will also serve to trap heat inside.
Place your dish of food inside the box and position your thermometer so it can be seen through the window.
Use a ruler or sturdy piece of cardboard to hold the flap open. Focus the direction of the flap so that light enters the oven window. Keep the flap in the same position for both parts of the data collection.
Data collection:
Place the food to be cooked in your dish and inside of your oven. Position the thermometer so that it can be read without opening the box if possible.
Place the solar oven outdoors (preferably between the hours of 11am and 1pm). Have the oven face directly south. *Note* You should try to place your oven in an area that has direct sunlight and is not obscured by trees or other structures. Make sure your oven is placed in the same location on both days.
Record the temperature before you begin and then again at 15 minute intervals for 1 hour. *Note* Be sure to use an oven mitt if you need to reach inside the oven to check the temperature, it may get quite hot.
Bring the oven indoors and allow the temperature to cool before beginning the next part of data collection.
Repeat steps 2 and 3 but this time face the oven toward the north. It is best if you do this at the same time of day and on days with similar weather (preferably two sunny days).
Hypothesis:
Using your knowledge of your position on the Earth and the position of the sun, based on the season and your geographical location, make a prediction about which direction your solar over will need to face in order to capture the most heat. Remember to put your hypothesis in an “if/then format” that mentions the variables in the experiment.
Procedure:
Summarize the steps that you took to complete this experiment; the procedure should be written in 3rd person and present tense, and it should give enough information for someone to repeat the experiment using only your procedure. Make sure to include any modifications you make.
Data:
Include a picture of your solar oven here:
Analysis:
Include a line graph to show the change of temperature in your oven over the course of your experiment. Be sure to include a legend that indicates which line represents the North-facing oven and which represents the oven that was South-facing.
Post-lab Questions:
What changes could be made to the construction of your solar oven to improve its efficiency?
Make a prediction of what temperature you would have recorded after 1 hour if you faced your solar oven to the east or west. Explain your prediction.
If you were building a home in Sydney, Australia and wanted to install solar panels on the roof, which direction should the panels be oriented in order to maximize their amount of sun exposure? What are two benefits to using solar energy instead of fossil fuels? What are two drawbacks of solar energy? Are there certain locations on Earth where solar energy would not work well as the only energy source to power homes? If so, where and why?
Conclusion:
Write your conclusion below. Don’t forget to discuss your hypothesis and use your data to support your conclusion. Talk about the concepts you learned and how they connect to the previous lessons and to real life. Evaluate the experiment itself and think about how it might be improved or expanded upon. Your conclusion should be 5 or more sentences in length.
