Pizza Box Solar Oven Lab

Group: Lauren Masaitis, Ziyu Zhan, Zhongfan Yang

  

For our final assignment this semester, we were instructed to design a laboratory exercise for other students in our class that teaches a concept of energy and sustainability that we have learned in this class. Ziyu, Zhongfan and I chose to explore the relationships between thermal energy, temperature, mass and specific heat, using a marshmallow, which has a specific heat capacity of 2.10 J/(kg°C) and a mass of 10.66 grams inside of a pizza box solar oven. We will measure the temperature inside the pizza box solar oven at set time intervals, as well as the temperature of a marshmallow at the beginning and end of the experiment.

The thermal energy of a substance is the sum of the kinetic and potential energy of its molecules. Thermal energy and temperature are related. When the temperature of an object increases, the average kinetic energy of the particles in the object increases. Because thermal energy is the total kinetic and potential energy of all the particles in an object, the thermal energy of the object increases when the average kinetic energy of its particle increases. Therefore, the thermal energy of an object increases as its temperature increases.

Heat is thermal energy that flows from something at a higher temperature to something at a lower temperature. Heat is a form of energy, so it is measured in joules (the same unit that energy is measured in).

As a substance absorbs heat, its temperature change depends on the nature of the substance, as well as the amount of heat that is added. The amount of heat that is needed to raise the temperature of 1 kg of some material by 1°C is called the specific heat of the material. Specific heat is measured in joules per kilogram degree Celsius [J/(kg°C)].

The thermal energy of an object changes when heat flows into or out of the object. If Q is the change in thermal energy and c_p is specific heat, the change in thermal energy can be calculated from the following equation: Q = (m)(c_p)(ΔT).

To begin our procedure, we needed to construct a solar oven from our pizza box. After our box was constructed, we were able to begin our experiment. We measured the temperature outside of the box and recorded it. We then set up the solar oven so that the opening of the box faces the sun and we angled the window flap so it directs sunlight into the pizza box. We then recorded the initial temperature of the marshmallow before placing it inside of the box. Once the marshmallow was inside of our box we started a timer and at five minute intervals we read and recorded the temperature of the inside of the box. Once we reached our 25 minute time interval, we opened the box immediately and recorded the temperature of the marshmallow.

Below is the data we collected and our analysis.

Analysis:

Data Collected

(In degrees Celsius)

Temperature Outside: 22°C

Initial Marshmallow Temperature: 22°C

Final Marshmallow Temperature: 29°C

Time (minutes)	Temperature (°C)
0 minutes	22°C
5 minutes	29°C
10 minutes	40°C
15 minutes	52°C
20 minutes	60°C
25 minutes	65°C

1.    Calculate the change in temperature of the marshmallow.

2.    Calculate the mass of the marshmallow.

3.    Identify the specific heat capacity of a marshmallow.

4.    Calculate the amount of thermal energy gained by the marshmallow.

·      The beginning temperature at 0 minutes was 22 °C.

·      The ending temperature at 25 minutes was 29 °C.

·      The change in temperature of the marshmallow is 7°C.

·      The specific heat capacity of a marshmallow is 2.10 J/(kg°C).

·      The Mass of a marshmallow is 10.66 grams.

Q = (m)(c_p)(ΔT)

Q = Δ(Thermal Energy)=”heat”
m = mass
c_p = specific heat capacity

T = temperature

·       Q = .01066kg2.10 J/(kg°C)7°C

Q= .156702 J

5.    Graph the change in temperature of inside the solar oven.

6.    Calculate the rate of change of the temperature of inside the solar oven.

·      Rate of Change = (y₂-y₁)/(x₂-x₁)

·      Rate of Change = (65-22)/(25-0)

·      Rate of Change = 1.72 (°C/minute)

Two things that we are able to conclude after conducting our experiment are radiation and thermal energy. Solar energy radiates from the sun to the Earth and gets trapped within our oven and this produces thermal energy within our marshmallow. When radiation strikes a material, some of the energy is absorbed, some is reflected, and some may be transmitted through the material. When a material absorbs radiant energy, the thermal energy of the material increases.

There are also a few variables to consider with our experiment.

1. We were not able to conduct this experiment outside on a warm day in the direct sunlight. If that were possible, we may have been able to get better results and a higher temperature in our oven.
2. There are ways that heat could have been lost from our solar oven:

•       The ground could have absorbed some of the heat

•       We could add more insulation to the bottom of the solar oven

•       Air was escaping out of cracks of our oven

•       We could add more tape to our box to make sure there are zero cracks

•       The amount of sunlight on the box was not consistent

•       We could add more flaps to the box to direct more sunlight into the oven