Watch the eclipse online:
“Live video streams of the August 21 total solar eclipse, from NASA Television and locations across the country, will be available on this page”: https://www.nasa.gov/ec
12 p.m. EDT (9:30 pm Indian Standard Time)- Eclipse Preview Show, hosted from Charleston, South Carolina.
1 p.m. EDT (10:30 pm Indian Standard Time)- Solar Eclipse: Through the Eyes of NASA. From Portland, OR: “The Comfort Suites in Corvallis normally costs about $128 for the night, however, during the weekend of the eclipse, rooms are going for as much as $1,300.” http://koin.com/2017/08/16/hot
More on the eclipse: https://www.timeanddate.com/ec
Stay with most recent partners for the lab activity during the second part of class.
What is a flame?
In class answer the following questions on lined paper. Include your name and period. When you are finished take a picture of what you have written and upload in your digital science notebook for the class. You may use your notes–you may access your DSN, but do not visit any other online site. Do not consult with other students.
- Compare your observations of the candle flame with the explanation offered in the video.
- What is your explanation for relighting the candle without touching it with a flame?
- Why do you think a candle will light and burn right side up but not upside down?
- Use sketches and words to offer an explanation for why the candle eventually burns out when enclosed by a jar or flask
- Use sketches and words to offer an explanation for why water rises in the inverted jar that is placed over a burning candle that has been placed in a basin of water.
- What is your best idea for why Michael Faraday compared the burning of a candle to the living process of respiration / metabolism (breathing and using food for energy)?
- In the Lego activity, what is analogous with a kind of atom?
- In the Lego activity, what is analogous with a kind of molecule?
- Each element is comprised of one kind of atom. Why do you think there are only a limited number of elements (just over 100)?
- What did you find out about 5 elements of your choosing?
- How did you interpret the haiku associated with your chosen elements.
- Why do you think scientists developed the idea of atoms and molecules to explain the behavior and properties of matter?
Periodic Table of Elements in Haiku http://vis.sciencemag.org/chemhaiku/
See this periodic table of videos (about elements) http://www.periodicvideos.com/
These references are important and useful. Make sure you examine them. Ask questions about whatever you do not understand. It is essential that you understand what evidence scientists have used to develop the explanation called: The Atomic Theory of Matter (also called the Kinetic-Molecular Theory of Matter).
- Evidence for the existence of atoms: http://www.alchemical.org/em/Handout24-Atoms.html
- Some-evidence-for-the-existence-of-atoms (1)
- You might find this article about Understanding Density useful. It discusses why students may have trouble with the concept.
- The first chapter from Reactions: The Private Life of Atoms by Peter Atkins
- Small but Mighty: The Molecule Called Water
- In Their Element (BBC) http://www.bbc.co.uk/programmes/b08p6q4r/episodes/player
See the directions below to begin to address the question:
If matter is based on discrete particles (atoms and molecules), how small must a particle be?
Just how big might a particle of matter be? Cutting matter down to size.
- Work with your candle partner.
- Find the mass of the small plastic dish. Take one crystal of potassium permanganate and place in the dish and find the mass. (Remember that the mass of the crystal and dish – the mass of the (empty) dish = the mass of the crystal. Record your procedure and results (always).
- Next put the crystal and dish under the microscope (Magiscope). (Be sure you know how to use the scope properly.) Record your observations. Make a sketch. Take photos with your Ipad.
- Use a ruler to estimate the volume of the crystal.
- Put the crystal of potassium permanganate in a test tube. Add 1 cm3 of water. Dissolve the crystal completely by shaking vigorously with your thumb over the end of the test tube. Then add water to a total volume of 10 cm3 . This is a ‘10 times’ dilution. Pour this 10 cm3 of purple solution into a 100 cm3 beaker and then fill up the beaker with water. This is now ‘100 times’ dilution. Fill the 10 cm3 test tube with this solution and throw the rest away. Dilute this again in the beaker to 100 cm3 . It is now a ‘1000 times’ dilution.
- Save samples of your dilutions. Arrange them in a row and take a picture. See this:
- How many times can the solution be diluted by a factor of 10 before the color is so pale that it is just visible?
- *The final dilution factor indicates that if matter is made of small particles, that these particles must be very small.
- FYI–Potassium permanganate has the chemical formula: KMnO4–this means there is one atom of potassium (K), one atom of Manganese (Mn), and 4 atoms of Oxygen (O) in one molecule.
Points of reflection:
- How do you imagine that light interacts with matter? What makes the crystal and solutions purple?
- How do you think light interacts with your eye?
- What do you think happens when something dissolves?
- Why would more of one substance dissolve in a certain amount of water than another substance? Why would there be differences in solubility?
- What differences do you think there are between dissolving and melting?
- What are your own questions and ideas?