Science at Bangor & in the News
After reviewing what we learned before break, we spent the week in chemistry describing matter and learning how units of matter come together. We talked about how mixtures, compounds, and elements are different at the level we can see and at the particle level. One of the characteristics that we can observe is solubility. Some substances will dissolve in other substances, like sugar dissolving in water. However, there are some substances, like ethanol, that sugar won't dissolve in. The photos below show a sugar cube that I placed in ethanol during first hour on Tuesday (1/5). The last photo was taken today (1/8) after school. So if we have a sample of water & one of ethanol, but don't know which is which, we could throw a sugar cube in each & see which one sugar dissolves into. If sugar dissolves, the sample is water. If the sugar cube stays whole, the sample is ethanol.
We also learned that compounds have distinct characteristics from the substances used to form the compound, but in mixtures the components keep their characteristics and the overall characteristics of the mixture are an average of the components. The beaker on the left (W) has water with a fully dissolved sugar cube (I promise there was a sugar cube dropped in it!), the beaker in the middle (E) is the same beaker of ethanol shown above, and the beaker on the right (50) has a 50/50 mixture of ethanol and water. Some of the sugar dissolved, but there is still a pile of sugar on the bottom of the beaker (it's on the right side of the beaker).
The big news in chemistry from over winter break is that chemists just synthesized the elements to fill out the last (7th) row of the periodic table. There were 4 elements missing that were just approved by the International Union of Pure and Applied Chemistry (IUPAC). The elements were made by scientists in Japan, the US, and Russia. The scientists that made the elements get to give the elements their permanent names. Within the next 6 months, the elements will be named & a new official periodic table will be issued. For more information, see the article from Chemical & Engineering News.
We began the last unit before the final exam in Science 9. Students were able to observe particles moving. After I lit a candle in one corner of the room, the scientists nearest the candle could smell the candle first, and gradually the students further and further away could smell the candle too. If particles didn't move, the smell particles would never have gotten to the other side of the room. Dropping food coloring in warm and cold water at the same time showed us that particles at warmer temperatures move faster than particles at cooler temperatures (pictures below). The food coloring quickly spread in the flask with warm water and took much longer to spread in the flask with cold water. We spent the last part of the week talking about pressure. Sucking the air particles out of a trash bag that a student volunteer was sitting in caused the bag to give the volunteer a hug (picture below). The air particles in the room were bombarding the bag, but without air particles in the bag to push back, the bag was pushed against the volunteer.
It was a big week in the classroom & in chemistry! We've got next week and part of the week after before we take final exams. I hope everyone is starting to look over their notes from early in the semester, eating healthy, & getting plenty of sleep in preparation for exams. Have a great weekend, Vikings (and everyone else)!