A. Mindful moment.
B. Review previous entry in DSN. (We have interrupted our study of matter to introduce an upcoming unit on astronomy. There are several purposes for the interruption. One is to give you time for observation of both solar and lunar cycles. Our last class fell just after the autumnal equinox. It is a good time to watch the changes in the position of the sun at sunrise, local noon, and sunset as we move toward winter. The other is to raise your awareness of objects and their apparent motions in the sky to prepare for WOW 8 when you are outdoors in an area with less light pollution and air pollution than Delhi. Interestingly, stars are element factories: < https://www.sciencelearn.org.nz/image_maps/50-universal-element-formation >. Check out Kim Boekbinder’s astronomically inspired pop music: Stellar Alchemist <https://www.youtube.com/watch?v=ENJKo5jqjUw>. Brian Green discusses stellar evolution and the creation of the elements : <https://www.youtube.com/watch?v=DEw6X2BhIy8>)
C. Preview today’s blogpost.
D. Create DSN entry today in Matter folder.
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Examine your fresh water and salt water evaporation beakers. Record your observations. Try to redissolve the salt. Then rinse your beakers well and return them to the counter.
Work with a partner that you have not worked with before (update your collaboration chart), make a 50 ml solution of magnesium sulfate (Epsom salt) and another 50 ml solution of sodium carbonate (Washing soda). Keep a record of how much of each solute you add–the solutions should not be saturated. Leave no solid undissolved. Find the total mass of the beakers and solutions (as picture below). Use clean and dry plastic cups to bring materials to your table.
Next pour solution 1 into solution 2. Do not spill. Observe what happens and describe in words. Take pictures. Measure the mass after mixing. Be sure to keep both beakers on the balance.
Share your data on the class spreadsheet:
See the results from Sci 8 1718:
Here is a description of the reaction in words:
sodium carbonate + magnesium sulfate —-> magnesium carbonate + sodium sulfate
NaCO3 + MgSO4 –> MgCO3 + NaSO4
Put 5 grams of sodium hydrogen carbonate (baking soda) in a small flask. Put 100 grams of vinegar (5% acetic acid) in a beaker. Find the mass of the flask and baking soda, the beaker and vinegar, AND a dropper as pictured. Next add drops of vinegar to the flask. Observe what happens. Describe in words. Take pictures. Continue adding until the baking soda has disappeared and no more reaction is apparent. Be very careful no to spill any material. Add the vinegar slowly so no material bubbles or splashes out of the flask. Find the mass at the end of the reaction. Use clean and dry plastic cups to bring materials to your table.
Enter your results in the class spreadsheet:
See the results from Science 8 1718:
A description of the reaction:
Sodium hydrogen carbonate + acetic acid —>Sodium acetate + water + carbon dioxide
Be sure to record your observations, thoughts, discussion points with partner, and questions. Make a rich and thorough DSN entry for these two experiments.
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If there is time: Make saturated solutions with 5o ml of hot water and various substances like: magnesium sulfate, aluminum potassium sulfate, copper sulfate, and maybe others. Put each solution (separately) into its own labeled petri dish and set aside for evaporation.