Category Archives: Grade 11

Solutions

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https://www.climatevisuals.org/images?f%5B0%5D=theme%3ASolutions&id=1096
Compost in Johannesburg
-Johannesburg, South Africa, 2004
-they are learning how to grow there own vegetables organically which has used less fossil fuel-fertilizers and chemical pesticides. soil erosion and water shortages and health effects on growers are less than conventional farmers.
-For most people this would be a good way to consume vegetables. Some cons are it takes time, money, resources, and land space. Pros are up above and also it would be more healthy for you. this is not that effective because most people can’t grow there own food.
Solar Cooker
-Burkina Faso
-a solar cooker uses energy from the sun to cook food such as meat, vegetables, etc. Solar coolers can keep more nutrients in food. in some countries this could be helpful because some people have to walk a long way to get fire wood. It is clean and emits less fuels and is economically good. this uses less wood which can help to preserve our forests. Biomass and petroleum fueled cooking fires pollute the air and contribute to global warming.
-Solar cooker cons are they can only be used when sun is out. This could be a alternative when going camping, etc.

Wave Interference

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Destructive Wave Interference  :

When a crest and a trough come in contact and cancel out. The energies combine and work against each other.

Constructive Wave Interference :

When two crests or two troughs from separate sources combine energies to displace the medium. When they both meet the amplitude becomes larger.

Noise cancelling headphones: They use wave interference to eliminate unwanted sound by creating a destructive interference that cancels out the outside noise before in comes in contact with you.

Thermos Challenge

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Prototype #1

Prototype #2

Prototype #3

Prototype Procedures

Prototype Graphs

Final Thermos

In our final thermos, we used a styrofoam cup, a paper cup, 1 foam insulator, and 6″ by 3″ aluminum foil around cup and 3″ by 3″ for lid. The price was 3$ and the starting temperature was 80 degrees and lowered to 56 degrees which resulted in a 24 degrees difference.

We decided to use aluminum foil because it is a good insulator and reflects heat back to the source. The shiny side had to be facing the cup so the heat was reflected back. The aluminum foil was wrapped around the Styrofoam cup. The styrofoam cup is a good insulator because in it there are trapped gas bubbles. Gasses obstruct heat conduction because their molecules are far apart and make it difficult for other molecules to collide with them. We then put the styrofoam cup wrapped with foil and foam insulation in a paper cup. We choose the paper cup because it had a lower thermal conductiviy than a plastic cup. There are air pockets in-between the two layers of paper and plastic. Then The aluminum foil as a lid with the shiny side facing the water to reflect the heat back in. At first we didn’t thin aluminum foil was the best option because it absorbs heat but we researched more and found out its good to reflect heat back to the source. We tried using a plastic cup in prototype #2 because it was cheeper than a paper cup. After we realized paper would be a better investment because the plastic cup was moist after and didn’t do a good job of keeping the heat in. Another problem we realized after prototype #3 was where the lid was placed.  We had a Styrofoam cup inside a paper cup with foam insulation and cotton balls. We then placed the masking tape on top of the paper cup. The heat was escaping the styrofoam cup and effecting the cotton balls and foam insulation. For our final thermos we decided to put the lid around the Styrofoam cup only which made a big difference.

Geography

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-In Sweden they convert their garbage into usable energy. They provide direct heating to 950,000 households and electricity to 260,000 homes. They recycle and sort their trash and less then 1% ends up in landfills. They also import trash from other European countries to fuel its power needs. They ask other countries for their trash because they run out.

-In India, a chemist came up with a method to pave the streets with plastic. They have transformed common plastic litter into a substitute for bitumen. This method saves money as well, the cheaper plastic substitute replaces as much as 15% of the more expensive bitumen usually used.

These countries have made methods that help with their environs such as Sweden, they have made their waste into to energy as heat and heat homes and that helps them because it gets very cold. We should many methods and try them.