John Scavo [Richards Voc HS]

• Take seeds from flowers and place them on a plate with a paper napkin on them. (Students don't realize that the seeds are inside the wilted flowers.]

• Use H₂O [water] for one set and a solution of RAPID GRO^TM on the other set, to see how they grow.

• The students should look at the setup each day and record data.

• Another method is to use a 2 liter bottle that is cut about 2/3 of the way down, to make a terrarium.

• By starting the seeds this way, more of the seeds germinate, so you get a better yield. If you use GROW-LITES^TM you need to use a fan to strengthen the stems and have the lights on in cycles, rather than continuously.

  Pat Riley [Lincoln Park HS]
  

  1. Examples of physical and chemical changes are easy to find, but examples of sublimation that are inexpensive are harder to find. One example concerns room air fresheners [important products indeed!-PJ)].

  2. Next we worked on balancing equations for chemical reactions.
     1. We first identified certain compounds that are easy to work with.
     2. Then we discussed what happens in combustion of natural gas:

        [CH₄ methane and 0₂ [air] combine to make CO₂[carbon dioxide] and H₂O [water] .

        ...the unbalanced reaction equation ...
        CH₄ + 0₂ ---> CO₂ + H₂O

     3. By using the large plastic balance we were able to balance the equation by placing more CH₄ icons or more H₂O icons on the left side, or more CO₂ or H₂0 on the right side, until the arms of the balance evened out. We then took the CH₄ and 0₂ icons from the left side, and put them on the board. Then we took the CO₂ and H₂0 icons out of the right hand side, and placed them on the board.

     4. We then counted how many C's and H's were on the left and right sides of the board, and tried to even them out with the number on the right side, since we must follow the law of conservation of atomic species [no cold nuclear fusion, please!-PJ],

     5. Once we had all atomic species balanced we put the icons back on their respective sides, and the scale balanced. We then placed the number for each compound before its symbol, getting

        3 CH₄ + 6 0₂ ---> 3 CO₂ + 6 H₂0

     6. Then we tried the same thing with C₂H₆ [ethane], getting

        2 C₂H₆ + 7 0₂ ---> 4 CO₂ + 6 H₂O

     7. The element icons were made of construction paper of the same color and size. Metal washers were placed on the back of the paper to make the weights proportional to the corresponding atomic weights. [mass, actually -PJ]

1. He had 2 solutions that he poured into separate glasses and then mixed them together. The clear liquids turned a red color.

2. He then divided a the mixture into 3 parts and put some of the original solutions into separate glasses. They got darker.
   A + B ---> C (red)
   C + A ---> C
   C + B ---> C
   Since the colors got darker this showed that there were all three compounds in each solution. So the equation would be
   A + B <===> C (equilibrium).
   The specific reaction was
   Fe⁺⁺⁺ + SCN^- <===> FeSCN⁺⁺⁺