Making a Solar Home Out of Colored Construction Paper This creative workshop asks students to make their own solar home model out of colored construction paper. It teaches them about residential photovoltaic solar installations and connects them to what they learned from the Total Solar Expert kit. The photovoltaic panels made out of aluminum foil will be placed on the home s rooftop and the small propeller over the chimney will let students experiment with the effects of the sun s heat by illustrating how a solar chimney power plant, or solar updraft tower (SUT), works. This activity connects art, geometry, science and technology. Goals > Make a solar home model. > Teach students about different types of solar energy (thermodynamic and photovoltaic). > Understand that warm air rises. Supplies for Making a Solar Home A tea light candle A bendable plastic straw, like the ones that come with fruit juice boxes for example. A push pin Three A4 sheets of paper in different colors, with a paper weight of around 160 to 220 grams (dense, dark colors are better because they will absorb more heat). Aluminum foil (preferably thick) Scissors Glue A ruler A pencil A round-tip pen (such as an empty ballpoint) Printed templates 1
Instructions Paper Solar Home 1) Print and then cut out the templates (pages 6 and 7) along the solid lines. An adult can make a slit with a cutter to help the students cut out the opening (hole) for the chimney. 2 3 4 2) Using a pencil, trace the outline of the templates on the following sheets of paper: 1st sheet of colored paper: the home s two façades. 2nd sheet of colored paper: the roof. 3rd sheet of colored paper: the chimney. Aluminum foil: the two photovoltaic solar panels. 3) On the colored paper sheets, draw the dots using a ruler and pencil. 4) Cut out the resulting shapes, then make the folds. 5 5) Glue the home s two façades together, then glue the chimney onto the roof. 2
Paper Solar Home (cont.) 6 6) Carefully draw the photovoltaic cells using the round-tip pen; then glue the solar panels onto the roof. See the elementary school Total Solar Expert kit for a picture of what a photovoltaic cell looks like. 7 7) Lastly, glue the roof comprised of PV panels and the chimney onto the house s façades. Tip: Flip the house to make gluing easier. 3
Propeller 1 2 3 1) Separate the tea light candle from its aluminum base. 2) Cut off the sides so that all you have left is the bottom disc. 3) Make eight cuts around the edges of the disc and carefully fold up the fin-shaped blades so that the whole thing looks like a propeller. 43 4 6 4) Pierce the center of the propeller with the push pin. 5) Cut off the bottom of the straw (total height 15 cm). 6) Using the scissors, split the bottom of the straw in half, stopping six centimeters below the bend. We recommend doing the cutting in two steps, first one side, then the other. 7 7) Stick the pin into the straw so that the propeller hangs five centimeters above the middle of the chimney. Slide the split straw onto one of the chimney s corners. 4
To rotate the propeller: 1) On a warm summer day, place the home somewhere in the sun, but protected from drafts (to avoid skewing the propeller s motion). Examples include in the shelter of a bay window, under an aquarium or bell jar or in the rear window of a car. 2) If it is an overcast or windy day, you can simulate the sun s heat by sliding a lighted tea light candle into the house (under adult supervision only). Understanding How the Propeller Works When sunlight hits an object, the object absorbs some rays and reflects others. Generally speaking, dark colors absorb more heat than light ones (see the Colors and materials: Are they equal under the sun? How and Why? workshop). For example, a black car in the sun will always be hotter than a white one. Here, the home s dark-colored paper absorbs the sun s rays, which are converted to heat. The inside of the home warms up, but cooler air comes in through the doors and windows near the ground. Since warm air is less dense than cold air, it rises and escapes up the chimney, creating an updraft inside. The propeller, which is in its path, captures this continuous air flow and starts to turn. > To Build on the Lesson A cluster of solar homes will create a brightly colored miniature village. Get the propellers moving and shoot a short video. Now all you have to do is share it on the school s blog so that parents can admire it! You can connect the lesson to hot air balloons to explain why warm air rises. Invented in 1782 by the Montgolfier brothers, hot air balloons fly using hot air, which is lighter than colder air. The air in the envelope is warmed by a burner, which allows the balloon to rise, carrying the basket and people in it. To stay aloft, the balloon needs air that is heated constantly. The hot air/colder air property lets you adjust the balloon s altitude: the hotter you heat its air, the higher the balloon flies. Conversely, if you let the air cool, the balloon descends. Its lateral drift, on the other hand, is determined by the wind. The pilot cannot influence it, except perhaps by rising or descending to catch a particular thermal. Source: http://www.jaitoutcompris.com/questions/comment-fonctionne-une-montgolfiere-3215.php (in French only) 5
Print out at full size (full scale) on A4-size paper, preferably thick. One template per student is enough. Solid lines: cut-outs. Dotted lines: folds.
Solid lines: cut-outs. Dotted lines: folds. Template for the solar panels, in aluminum foil. Template for the solar panels, in aluminum foil. Template for the chimney. Print out at full size (full scale) on A4-size paper, preferably thick. Area to cut out (chimney). Template for the roof.