Density

This week we practiced measuring volume of different objects. We measured blocks using the formula length x width x height = volume with the units in cubic centimeters. We discussed the difference between the accuracy and precision of our measurements and how to use our rulers effectively. We considered how many significant figures we could use in our calculations as well. We also reviewed how to measure volume using the displacement method with water in a graduated cylinder. There were a lot of students visiting upper school this week and we had a block schedule so it has not been a regular week. Tuesday and Wednesday during the block schedule we did a lab activity that compared the density of pennies minted before 1982 and after 1982 when they switched to mostly zinc. The Penny Density Lab gave us practice measuring volume using the displacement method, measuring mass on the electronic balance, and calculating density using our formula of Density = mass divided by volume.
We collected homework on Thursday and assigned new homework: Read chapter 2.3, pp. 53-60. Answer questions 3, 5, & 6. Due on Thursday, January 19th.

Chemistry notes and some simple investigations

Wednesday and Thursday we took some notes on Chemistry terms and definitions. We looked at density and the difference between floating an object and resting a paperclip on top of the the surface of water without breaking the surface tension.  We reviewed the formula for density (Density=mass/volume) and the standard units: grams per cubic centimeter (g/cm3)

Thursday we discussed the differences between physical and chemical changes and measured the temperature changes that take place when we mixed Calcium chloride and water and baking soda and water. Here are the notes: Chem Notes - January 4, Physical Change versus Chemical Change, Hot and Cold Reactions.

Starting Chemistry

Today we started our Chemistry unit. We had a pop quiz of sorts that I called a "Brain Dump." We reviewed three units of temperature measurement: Fahrenheit, Celsius, and Kelvin. We reviewed the different terms for phase change like melting, freezing, sublimation and evaporation. Everyone got a copy of the Periodic Table that we will be using as a resource during this unit. The WebElements website is a great resource for information from the periodic table and the we are using their printable version of the periodic table. Check out their website at: http://www.webelements.com. It has good interactive features and links to other sources. We also watched part of a short video about Hydrogen from the "Periodic Table of Videos" from the University of Nottingham. Check out their website for fun and informative videos about most of the elements and several of their favorite compounds as well.
We passed out textbooks today "Science Source" and assigned homework that is due on Friday, January 6th. 
Read Chapter 2, "What is Matter?" pages 38-44 and answer questions 3,4,5, & 8.

Trash Talk and Wrapping It Up

Friday we watched a video clip from the TED talks by Charles Moore about the plastic trash that is ending up in our oceans. You can see it here: The Great Pacific Trash Island. We keep generating more and more plastic and our recycling efforts are not keeping up with it. We looked at the anatomy of an landfill at the How Stuff Works website. Modern landfills are designed to seal away our wastes so that it won't contaminate our water supplies and to safely vent off methane gas, that is a significant greenhouse gas. We looked at maps of the Orange County Landfill and discussed the history and the current issues surrounding the future of this site. We compared this to the Puente Hills Landfill that takes most of the garbage for Los Angeles, at 1300 acres, it is one of the largest in the US.
Monday and Tuesday we are putting the finishing touches on our projects, "It Costs What?" These are due on Wednesday, December 14th.

Project Work on "It Costs What?"

Tuesday, Wednesday and Thursday we worked on our projects. We have been researching the sources of the materials used in manufacturing our products and the resources consumed and pollution created at each step. Products that are being researched include breakfast cereals, chocolates, lipstick, shoes, coffee and tea drinks, violin bows, and basketballs. These projects should be finished up by this weekend and then will be presented on Wednesday, December 14th.

The stories of our stuff

Today we read from "Confessions of an Eco-Sinner," by Fred Pearce. In this book he goes to the source of some of his food, clothing, materials and the energy that he uses most days. We read about cotton production in Australia, the US and Uzbekistan, the three largest producers in the world. In particular we learned about how much water is used to make a tee shirt (33 bathtubs worth!) and the pesticides used to grow cotton (one quarter of all pesticides used on crops in the US). We also read about the plight of the banana and how it is facing eventual extinction from disease unless we find a new source of genetic diversity to build up its resistance to these threats. This lead to more stories about the limited varieties of the foods that we eat and the need to preserve genetic diversity in order to have healthy food supplies. The readings sparked some good discussions about genetically modified foods, the use of animals in research and synthetic versus natural materials for clothing. We will continue to research our stories of the stuff we use (It Costs What?) and these poster projects will be due on Wednesday, December 14th.

Friday we watched most of a documentary called, "T-Shirt Travels" about the used clothing market in Africa. It followed the story of a young man in Zambia who buys a bale of used clothing from the US and sells it in his hometown in order to make a living. It turns out that the number one export from the US to Africa is used clothing and this has had a big impact on the economies of African nations. It follows up on the story of our t-shirts and what happens to them after we drop them off at used clothing places like the Salvation Army or Goodwill. Here is a link to a summary on PBS: http://www.pbs.org/independentlens/tshirttravels/film.html

Here is a link to where you can click on each stage of the travels of a t-shirt as it makes its way from US charity bin to African marketplace:
http://www.pbs.org/independentlens/tshirttravels/track.html

"It Costs What?" Projects

We have been working on our "It Costs What?" projects today and on Tuesday. Yesterday the 4th years went on a field trip to the NC Museum of Life and Science to see the RACE Exhibit. Check out their website about the exhibit at NCMLS.org. The exhibit looks at race from cultural and scientific viewpoints.
The "It Costs What?" project is looking at an everyday object like a tee shirt and tracing its path from natural resources to finished product that we buy in a store. Along the way different resources are used and pollution is created, these are the hidden costs of the product. Students are working individually and in pairs to research their products and then will create a poster of their findings. Here is the project outline and rubric.  Last Monday we did a values line up called "Where do you stand?" in which I read a statement and then we lined up according to how strongly we agreed or disagreed with the statement. This sparked some good discussions. Here are the questions, we had time for 4-5 of them. We finished that day listening to a radio program from the show "Marketplace" from American Public Media about a "Well traveled Breakfast." The author traces the sources of the foods that his family eats on a typical morning. You can listen to the story and read about it here: Marketplace, A Well Traveled Breakfast.