Tuesday, July 5, 2011

Building Solar Ovens

Building Solar Ovens can be fun, but take your time.
Many variables can change the temperature of your final product. 
See if you can detect what those variables could be.

Materials needed:
4'x4' sheet of cardboard 
2 - 8.5”x11” pieces of Mylar transparency
duct tape (1.5 inch or greater width)
aluminum foil
measuring stick
Sharp instrument to cut cardboard (IE.x-acto knife) Parent supervision recommended, of course.
Protractor
1 thermometer
Black paint
White or yellow glue (yellow is better)
newspaper for insulation or packing foam





STEPS:

  1. Outer box construction - The outer box has dimensions 10x10x10inches.  The box has no top, so simply cut shape A out of the first of the 4x4 sheets of cardboard.  Save the corner square since these will be used for the lid frames.  Once the "+" figure is cut, score on the fold lines to make folding easier, fold into the box shape, and then tape sides together.
  2. Inner box construction - The inner box has dimensions 6x6x6 inches.  The box has no top, so simply cut shape B out of the 4'x4' sheet of cardboard.  Once the "+" figure is cut, score on the fold lines to make folding easier, fold into the box shape, and then tape sides together.
  3. Paint the inside of the interior box black.
  4. Place interior box in outer box and fill with insulation material.  Make sure that the tops of the inner and outer boxes are at the same height.  (You must place about 4 inches of the insulation material under the inner box).  When using the newspaper, first wad the paper up into a ball and then place it in.  Do not put the paper in flat on the sides.  Always use the wadded up ball method and try to fit the paper in.
  5. Lid Construction - Cut out 4 frames from the 4 corners saved from Pattern A.  Each frame is 10x10 outer and 6x6 inner.  When you place the 4 frames on top of each other, they should line up.  Be as precise as possible. 
  6. If you have a single glazing oven (which is one Mylar), place your Mylar on top of the 4 pack, cut away the excess Mylar.  Tape the Mylar to the top of the 4 pack.   If you have a double glazing oven (two Mylar pieces), place one piece of Mylar on the top and one on the bottom of the 4 pack.  Again, cut away the excess, and tape the Mylar pieces to the 4 pack.
  7. Place the 4 pack with the glazing OUT (on top) over the inner and outer boxes.  Line up the inner box so that it is directly under the 6x6 hole in the top of the 4 pack.  This lineup is critical so that as much sun goes into the oven as possible.
  8. Build a collar by cutting a 2 inch by approximately 41 inch strip of cardboard.  Wrap the cardboard collar around the 4 pack so that the collar hangs down over the outer box and makes a fairly tight seal.  Tape the collar to the 4 pack, effectively making a lid for the boxes.  The lid should fit fairly tightly.  Do not tape the lid to the oven.
  9. Reflector Construction - Cut out your 4 reflector trapezoid panels based on your design (either 60 or 75 degree angles with the horizontal pieces.  (Parents will need to help here with the measuring and layout on the cardboard).
  10. Place the foil on the ground and place glue on the foil.  Now, place your panels on the foil so that they cover the glue.  Let dry a bit and then cut the foil around the panels so that the panels are now covered with foil on one side.  It is important that the foil remain as smooth as possible.
  11. Tape the foil panels together by lining up the sides and using the duct tape.  When done, you should have a square based pyramid with the top cut off.  The top should be a 6x6 inch square and the bottom dimensions are based on the angle that was cut.
  12. Place the 6x6 end on the glazing (Mylar) over the hole for the inner box.  Tape to the lid securely.  Do not tape the lid to the oven.
  13. Congratulations, you are done with the oven.
  14. Testing - Using the knife, poke a small hole in the side of your oven into the inner box so that it is centered in the inner box.  Push you thermometer through the hole into the inner box.  Use tape to plug the hole if the thermometer is not tight and steady in the hole.  Aim your oven so that it is pointing at the sun (we will help here).  Plot you temperature over time (every 4 minutes for 24 minutes should be good enough).  Graph the data and see how fast the oven heats up.  Compare different designs and different replications of the same design.

Saturday, July 2, 2011

Jane Poynter, a Biospherian

Jane Poynter came to talk with the STEM teachers about her research and experience in the Biosphere 2.  She spent two years inside the Biosphere2 living and learning about how to sustain life inside a man-made bubble without any help from the outside.
Click here to watch a video of her speech.

Ocean Biome

More images of the Ocean Biome.  Click here.
Learn more about the Ocean Biome.  Click here.
Linda and Stephanie going on the B2 ocean?  I don't think so!





Rainforest Biome

Read about the Rainforest from B2 website.  Click here.
More awesome images of the Rainforest Biome.  Click here.






Looking straight up.




Savannah Biome

See more pictures on this link:  Click here.
The following is a link from Bioshere 2 website with information about the Savannah Biome.  Click here.





Can you see how the leaves look like butterflies?

Coastal Fog Desert Biome

Read more information and see pictures on this link:  click here.