Monday, Feb 25, 2008 - 4A

Collected late safety contracts. Those who have not yet turned one in could not participate in the lab and just had to sit with their goggles on.

Went over green write-up sheet. Pointed out omission in data table, need to include a column for the height of the gas in cm.

Went over some additional procedures and precautions:
1. Put a lot of popsicle sticks in your burning test tube but don't completely cram them in so much that you won't be able to remove burnt sticks.
2. When we have a fire alarm, remove rubber tubing from the bucket of water, place it on the lab bench and then shut off burner and evacuate the lab.
3. When done burning (either no more gas is bubbling or the mason jar is full)
a. Remove rubber tubing from the bucket of water and place it on the lab bench away from the alcohol lamp
b. Shut off the alcohol lamp
c. Put the rubber band at the level of the gas in the mason jar
d. Call me over to burn off the gas. Lift the jar straight up to let the water come out and then quickly turn it over so I can toss in a lit match
e. Measure the height of the gas (distance to the rubber band) and be sure to measure the diameter of the mason jar (all in cm)
4. Take the charred sticks out with the forceps. Try to burn one in the alcohol flame.
5. Cap collection test tube with the solid rubber stopper, put your name on the test tube with masking tape and store in the test tube rack.
6. Rinse out glass L assembly and test tube. Put back in box and put box in proper place on cart.
7. Put away all equipment, put ring stands back the proper way
8. Wipe off lab tables
9. Wash hands.

In addition, last class we had problems with the mason jars floating. I suggested the students only put 4-5 inches of water in the bucket, not even half full.

Students redid the Day One of the lab which was interrupted last time by the fire drill.

I was very pleased with how well the students were able to set up and conduct the lab. They did a really good job. Most were able to get in two or even three burns and the cleanup (started at 2:30) was well done.

Talked about the lab write-up. For homework students should finish write-up of Day One. Doing the write-up in small chunks makes it easier than trying to do the whole thing at the end. Students should already have done the Material list, diagram, procedure, safety precautions. Now students can complete the observations, data table, calculations, and conclusions for Day One.

The final lab should be typed.

Next class we will complete the lab by doing the Day Two distillation. The entire lab write-up will be due a week after that, on Thursday, March 6.