8 October Science 8 Chemical reactions and evidence for existence of particles (atoms and molecules)

A. Mindful moment. Think of science journey questions: Where does it come from? Where does it go? What happens along the way? (From chemical reactions to earth cycles to the lives of stars)

B. Review previous DSN entry. Look at the results from 1718 and 1819.


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

How would you construct a histogram to show the pattern of mass change before and after this reaction using all the trials from the two years of grade 8?

Tomorrow is the new moon. It rises when the sun does. The moon is not visible on earth during this phase. Can you figure out why? (Hint: what do you know about light, reflection, shadows? Can you make a sketch of where the new moon is in relation to the earth and the sun? Why do we see–not see–what we do?)

C. Preview today’s blog.

D. Create today’s DSN entry in the matter folder.

E. Questions.

  • * * * * *
  1. Two-week window for revising and resubmitting summative project report on Mixing Ethanol and Water begins today. See Powerschool.
  2. Arrangement for issue 1 parent newsletter. Editors discuss plan.
  3. Carryout the following reaction:

Reaction 2.

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

NaHCO3+CH3COOHCH3COONa(in solution)+H2O(liquid)+CO2(gas)

Be sure to record your observations, thoughts, discussion points with partner, and questions. Make a rich and thorough DSN entry for this experiment–especially as compared to reaction before.

3. Crystals and crystallization:

Make saturated solutions of other substances provided. Pour a little of your saturated solution in a petri dish labeled with your names, period, substance, date and time. Set it on the counter top at the back of the room. You can set up one petri dish  / substance.

Take pictures.

What do crystals suggest about atoms? See this short video:

Mathematical Impressions: Attesting to Atoms


About rfrazier

AES profile = http://aes.ac.in/viewprofile.php?u=6946
This entry was posted in Science 8. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *