Did you know that the sun is made up of about 70% hydrogen? Or that hydrogen is the most abundant element in the known universe? Hydrogen fuel cells will be the future of alternative energy. They are already being used to power vehicles made by large manufacturers such as Toyota and Hyundai. Check out this article for a bit more on the emerging use of fuel cells to replace gasoline and time consuming electric models Hydrogen fuel cell powered cars. Article source: http://money.cnn.com/2012/03/15/autos/hydrogen-fuel-cell-cars/index.htm
Even though hydrogen is the most abundant element in the universe, finding free hydrogen gas is extremely rare because it bonds with other molecules to form compounds like water and natural gas. So one way scientists obtain hydrogen gas is through a process called electrolysis in which electricity is applied to H2O molecules to split the compounds into hydrogen and oxygen gases. Here’s a simple video on the very basics of electrolysis how electrolysis works. And we will give a small demonstration in class using a model we built to separate the hydrogen and oxygen from water molecules.
The focus of today’s lesson was what happens to trash after we put it on the curb for garbage collection and what trash consists of. Even though all of us are well aware that out of Reduce, Reuse, Recycle; reduction is the most important factor in waste management because of course if there is less waste in the first place then there is less that will ultimately end up buried in a sanitary landfill or burned in an incinerator (not including the option of recycling in this scenario).
The above pie chart explains the breakdown in the U.S.’s Municipal Solid Waste (MSW) consists of and from the categories above it is evident that paper/paperboard products make up the largest percentage of MSW. And the link above is a great resource for some facts and graphs on MSW in the U.S. and also on this link are some graphs that show the MSW generation rates and the MSW recycling rates.
The graph shows what appears to be a leveling off of waste generation per person which could be a good thing because of the importance of waste management. Hopefully in years to come we will see a downward trend to our total and to our per capita waste generation.
This graph shows the total amount of MSW in millions of tons being recycled and the percent of generation recycled. It is notable that around 1985 recycling rates skyrocketed and have been on the rise since then but unfortunately appear to possibly be leveling off (for now).
And all of the different types of MSW in the pie chart above can end up in one of three places: buried in landfills, burned in incinerators, or recycled. Of the U.S.’s MSW 55% is buried in sanitary landfills, 12% is burned/incinerated in mass-burn incinerators, and the remaining 34% is recovered through recycling. But today we focused mainly on the trash that gets buried in the landfills. You can’t just dig a hole anywhere you want and bury your trash. Landfills are an engineering marvel that follow strict regulations to prevent causing dangerous conditions for surrounding areas. Building a landfill is a science that is amazingly depicted at this site: http://deoracle.org/learning-objects/landfill-construction-model.html which shows and explains an animation of the sanitary landfill construction process from building to filling to management. Here is an example of the first diagram:
And even though we didn’t cover incineration in class yet here is a youtube video that explains how waste can be used to create energy: how a waste-to-energy plant works
