Experiments

Effect of Black Painting and Heat Flow Rate

Object

This experiment is going to test that how paint affects heat absorption. Use the collected data to calculate the rate of heat change and BTU. After comparison, we could choose to paint the copper or not. The last experiment is going to make sure it does not heat up too quickly or too slowly.

Theory

       Sunlight is solar radiation. When filtered through the Earth's atmosphere, this radiation hits the Earth as a combination of bright light and intense heat. Sunlight has a unique interaction with black objects. When we see colors in nature and elsewhere, it is actually reflected wavelengths of light. When all light is absorbed, there is no color, and only black remains. Dark-colored materials heat up much faster in sunlight because they reflect less of it than lighter materials and absorb heat more rapidly.

       In physics, describing the rate of water cooling down by evaluating the volumetric flow rate and temperature difference. We call it heat flow rate. The heat flow rate in a system can be expressed by the basic equation:

h = q / (C_p*ρ*dt)

where q = volumetric flow rate

h = heat flow rate

C_p = specific heat capacity

ρ = density

dt = temperature difference
Procedure
A. Testing the effect of black painting on copper

1.      Prepare a solar panel made of copper, a water circulate pump and a thermometer.

2.      Place the heating system under the sunlight and begin to circulate water for 15min.

3.      Paint the copper into black. Repeat step 2.

4.      Collect data in the following chart.

	Initial Temperature	Final Temperature	Temperature Difference
Raw Copper
Black Painted Copper

B. Calculate the rate of heat change

1. Repeat step 2 in Part A for different volumetric flow rates.

2. Collect date in the following chart.

Volumetric Flow Rate	Initial Temperature	Final Temperature	Temperature Difference

C. Testing the efficiency

1. Place the heating system under the sunlight and heat until the temperature of water reach 30 Celsius Degree. Track the time.

2. Double the volume of water and repeat step 1.

Volume of Water	Time