News from the Science Classroom!
6th and 7th grades!
Having done an excellent job on their science experiments for the science fair, students are now taking on the study of basic chemistry. They have been studying characteristic properties of substances. They learned how to measure mass with triple beam balances, and to measure volume by water displacement, or by measuring length, width and height. They used these skills to help them calculate the density of many different metals, woods, and plastics. Then they were able to identify "mystery substances" using the density.
We have also been talking about other properties, such as boiling point and freezing point (and trying to imagine how hot it is when metals "freeze" into solids, and how cold it is when oxygen "boils") We explored the idea of solubility, and how some substances dissolve easily, and others don't.
We posed the question, "How do we use characteristic properties to separate substances?" Students were challenged to use their knowledge of properties, to separate a mixture of sand, salt and sawdust. We worked on connecting the names of the properties (density, solubility, and boiling point) to the differences that made it possible to separate them.
Lately, we have been learning about atoms and elements. Students are thinking about just how small an atom is, and trying to make sense of the fact that they are too small to see, but we have evidence that shows us their properties. We are distinguishing between elements (made of one kind of atom) and compounds (made of more than one kind... chemically bonded together)
Our study of the periodic table is aimed at helping students know how to use it as a reference tool (not memorize it) We have been exploring what all the symbols and numbers mean. We wondered, together, why it is such a strange shape, with some elements sticking out at the top. Students were given data on each element, and asked to organize it themselves, based on as many different pieces of evidence as they could. They discovered that it's organized by atomic number and atomic mass AND by what the elements combine with and whether they are metals, non-metals or metaloids.
This past week was particularly fun for students (and me too). We have been looking at the differences between chemical changes and physical changes, and thinking about how chemical changes make new substances. We saw pure sodium metal react violently with water (it catches fire and explodes), and talked about how sodium, combined with a poisonous green gas (chlorine) makes plain old table salt! We also burned paper, saw chemicals combine to produce color changes, saw other chemical combinations produce gasses, and 7th graders even saw chemicals produce heat or cold. Our objective is to see the difference between a physical change and a chemical change, and to understand that after a chemical change, there are new and completely different substances.
Upcoming is another "figure it out yourself" lab (known as student "inquiry" in educational circles) involving several chemical reactions. Students will see four chemicals mixed, and evidence of several chemical reactions. Their job is to figure out which combinations of substances cause which reactions.
Soon we will turn our attention to weather, including how we measure pressure, humidity, temperature and wind, as well as how and why air moves, how clouds form, how we know when and where storms occur, and other weather-related learning. I am excited to look at data from our new electronic weather station, right at the school!
Throughout the year, 8th graders have been working on honing their informational writing skills. Scientists do experiments, but they also need to communicate clearly about them, and synthesize information they read about science topics. Clarifying one's ideas, enough to write clearly about them, is an important skill. The 8th graders wrote about the physics of roller coasters in the fall, they wrote about why planets orbit the sun, and why there are eclipses in the winter, and now in the spring, they are writing about a genetic disorder.
We have worked on a concise, clear, get-to-the-point writing style, that is different from story writing, and different from argument writing. We have worked on shortening our sentences, but using several short sentences in a row to get across a complex point. We have worked on coming right out and saying what needs to be said, with specific detail, but without too many extra words, and without introductory phrases that don't say much. Some students began the year with run-on sentences that included up to seven commas. They are learning to break apart complex sentences, and achieve a clean, crisp, concise style. Others started with such "concise" writing, that they left out most of the important detail that needed to be described. They are writing less vaguely now, with more specific terms, and fewer missed details.
I am so pleased with their efforts! The difference in their writing from the beginning of the year to now, is truly inspiring. They get many comments on their papers from me, and often feel somewhat overwhelmed. However, the improvements in the quality of their informational writing on the whole should make each of them very proud.
Our genetic disorder essay is currently in its third revision. Still to come, is the writing of a narrative story about a patient (fictional but realistic) who has the genetic disorder they wrote about. I will be looking for connections to their research, but also a sensitive, dramatic and realistic portrayal of the real life issues that face patients and families with these genetic disorders.