Solar Cooking: Second Experiment

Introduction
A solar oven uses energy from direct sunlight to cook foods. No fuel or electricity is required. It is desirable for people who wish to reduce their energy usage or utility bill. Since it does not use fuel, it is also very environmentally friendly in that it does not create any pollution by the burning of fuel.


Background
This experiment is based off of a previously conducted experiment Solar Cooking: First Experiment. The following suggestions have been implemented:

• Plastic wrap was used to cover the roaster instead of the solid lid
• Cashew butter was used to replace the oil in the recipe
• The solar oven was placed outside at 11:00 am

Also, upon research, it was found that brown sugar helps to add structure to gluten-free baking products. Brown sugar was made specifically to be used in this experiment.

Question
Can cookies be baked using the sun instead of an oven?


Hypothesis
Yes.


Prediction
It will take longer than baking in the oven, but the cookies will be successfully baked.


Materials and Methods

Equipment used:

• 1 small, black speckled roaster (lid not used)
• 2 mini cake pans
• cooking utensils and ingredients to prepare recipe for Chocolate Chip Cookies for 2 

Recipe modifications:

• A gluten-free all-purpose flour mix from a bakery in Pittsburgh called Gluuteny was used.
• Milk was not available and water was used instead.
• Oil was replaced with 1 tablespoon cashew butter, and water required was increased by 2 teaspoons.

Method:

1. Prepare cookie recipe using modifications described above.
2. Divide the cookie dough in half and place each half in a mini cake pan.
3. Place the mini cake pans in the roaster and place clear plastic wrap on top.
4. Place the roaster outside in direct sunlight.

Observations

Time	Outside Temp	Observation
11:00 am	80°F	Cookies are placed into roaster outside.
11:30 pm	80°F	Cookies seem to be firm, but not completely cooked yet.
12:00 pm	82°F	Cookies are somewhat firm and may be close to done.
12:15 pm	82°F	Cookies are brought inside to cool.
12:30 pm	82°F	A taste test determined that cookies were not done. Cookies were placed outside for more baking.
1:45 pm	84°F	Cookies seem to be much firmer. Experiment concluded and cookies taken inside to cool.

Analysis

It was determined that this experiment was a success. Cookies were successfully baked using a solar oven. The cookies were soft but firm enough to be picked up by hand. The softness of the cookies is thought to be due to the nature of the recipe used.

The use of cashew butter in place of coconut butter (as used in the previous experiment) eliminated the oiliness of the cookies. The reduced oil may have also led to the cookies baking properly in a solar oven.

The biggest change from the previous experiment which contributed to the success is thought to be the use of plastic wrap instead of a solid lid. The solid lid was thought to create a hot box which should bake the cookies, while the plastic wrap allowed the cookies to be heated by direct sunlight. Placing the solar oven outside before noon may have also contributed to the success.

Some changes are still recommended to be implemented in future experiments, to help monitor the baking more closely or to help shorten the baking time:

• Obtain an oven thermometer to measure the temperature inside the solar oven.
• Construct reflectors to direct more sunlight to the solar oven.
• Place food on a black (or dark) baking sheet inside of the solar oven.

Conclusion

This experiment has shown that baking using a solar oven is possible. The baking time was much longer compared to baking in a conventional oven. Further study is highly encouraged to determine how to shorten the baking time.