Solar S'mores

The sun is out and we are ready to enjoy a favorite summer snack.  Using poster board, cardboard, aluminum foil, glue, string, and clips, we created Copenhagen Solar Cookers for s'more science fun.  Once in the sun, the ovens heated up to 150'F in a matter of minutes and were able to melt the chocolate on our marshmallow fluff covered graham crackers.

Here is a video on how to build your own - How To Make Cogenhagen Solar Cooker.  We even made mini ones using 7"x7" poster board squares and 4"x4" cardboard center!

Future Solar Engineers

The Woodlawn students had a chance to experiment with solar panels and create a UV activated bead keychain at the "It Takes A Community" event.  Go Woodlawn Wildcats!

photo credit - Sherylita Mason

photo credit - Sherylita Mason

Water, water everywhere but not a drop to drink

Did you know that 1/6 of the world does not have access to clean drinking water?  That's over 1.1 billion people!  This week Rieke's 5th graders learned about the microbes all around us and which are the good, the bad, and the ugly.  Located near the school is Stephen's Creek watershed that has had high E. coli pollution over the last 10 years - E. coli is one of our sometimes good but sometimes bad microbes.  For this engineering challenge, the students were asked to purify the water from our creek with the SODIS method - using infrared and ultraviolet radiation from the sun to kill the microbes.  Each team chose a variable to test with their creek water - using baggies vs. glass bottles, black tarp vs. reflective surface, sari filtered water vs. SODIS treated water, aluminum foil boats vs. corrugated roof, ...  We allowed the experiment to run over the weekend and then the students tested their water with a bacterial/coliform petrifilm.  With these plates, bacterial colonies appear as purple dots on the pink plate.  E. coli colonies are purple dots with an air bubbles next to them.

Three days later, they observed the results.

Thankfully, our tap water did not have any detectable bacteria!

Stephen's Creek water - there are 8 E.coli colonies on this plate

From left to right - creek water, sari filtered creek water, SODIS treated creek water

From left to right - creek water, SODIS treated on a black tarp, SODIS treated on reflective surface

Beaver Engineering

Both humans and beavers are environmental engineers - able to modify a habitat which can change the landscape and species richness of a region.  This makes both of these mammals a keystone species and their behavior can affect the healthy and stability of their environment.  These Rieke kindergarteners were able to test their engineering skills as they took the challenge to use mud, sticks, and water to create a mini dam!

Cosmic Rays

How do you collect sunlight?  What can affect how much solar energy hits the Earth?  How can we save the energy from the sun?  These are questions that our 3rd and 4th graders asked as they collected data about our sun.  Using solar energy meters the 3rd graders predicted the best angle to collect the most watts/m2 and then set up an experiment to track the temperature and solar energy at a location for a week.  They found that temperature was a good prediction of how much energy they could collect from the sun but that clouds and pollution may affect how much radiation reaches the Earth's surface.

HOBO data logger graph - blue is temperature, black is volts

The 4th graders learned how to connect a circuit to use solar energy to charge a AA or AAA battery.  They made predictions on how long it would take to fill a rechargeable battery and collected data with a multimeter every 10 minutes over an hour.  It was a science/recess lesson!

Solar battery circuits chargers while the students played

Checking the connections after collecting data

Tracking the Sun

Sunflowers are able to detect and move to toward the sun by a process called heliotropism.  Our 5th graders were given the engineering challenge to mimic this process with four mini solar panels, a DC motor, popsicle sticks, and a glue gun.  As a team they needed to wire the panels to the motor so that when the tip of the 'solar house on its side' is facing the 'sun' (work light), the motor would stop.  But if they turns either left or right with the solar house, the motor would spin in the opposite direction.  The students were able to practice their 'engineering loop' and after multiple tries, fails, and brainstorming, they got it.

Simple Machines

What are a mechanical devices that have allowed humans to move, lift, push, and pull objects for centuries - Simple Machines!  The 1st graders were able to test how these devices help transfer their effort to solve a task.

• Wedges and Basic Wheel
• Can you transport a large box across the room?
• Screws
• Can you move water uphill?
• Levers
• Can one student lift 3 classmates?
• Pulleys
• Can you lift your classmate three feet off the ground?
  

Muon's in the air

Humans can only see part of the radiation from the sun - the visible light spectrum.  What about the unseen gifts from our local star?  Some are safe for humans and life on Earth, and other are damaging.  We discussed how our atmosphere protects us from some of the most dangerous forms of cosmic radiation - some of the ultraviolet spectrum, x-rays, and gamma rays.  Using a homemade cloud chamber, Rieke 3rd grade students were able to view a normally invisible safe cosmic particles called muons.