Wednesday, August 31, 2011

Lab safety and Variables 8/31/11

Announcements:


  • Quiz on friday!

  • Lab report on google docs is due friday too!

Homework:



  • Work on lab report

Body:


Today in class we watched a video on lab safety that told us many rules on how to not harm ourselves in the lab (kind of helpful ehh??) Like cleaning up after everything, not burning oursleves oh and KEEP THE DESK ROWS CLEAR OF BAGS Mr.Paek told us a story about how a kid got a concussion last year from tripping on a backpack and smashing his/her head onto the counter...ouch, lets not have a repeat. Then after the video we got 15 new pages to tape into our journal:



  • measurement practice pages

  • measurement lab

  • sig fig rules

  • scientific notation

After tediously taping all the sheets in we finally started in on some content! We went back to the page before the Alka Seltzer lab in our journals the page called variables and filled it in. Here were the responses we got as a class.


1. Indepent=amount of water


dependent=how tall the plant grew


C1=amount of sunlight


C2=same plant


2. Independent=different size of coffee filters


Dependent=how long it takes to fall


C1=same coffee maker


C2=same brand coffee filters


3. Independent=Different types of food


Dependent=temperature


C1=same heat source


C2=amount of water


4. Independent=concentrations of oxygen gas


Dependent=how they grew


C1=same type of plant


C2=amount of water


*note- The C1 and C2 can differ because there are many different possible control variables in each situation


After we finished that sheet we moved on to the first new sheet we taped in called Measurement-1. On this sheet we answered the first 3 questions


Reading 1- 42 cm, because it is a little past 40, but not too much


Reading 2-0.66 cm, beacuse its a little more than half way between .6 and .7


Reading 3-27.5 ml, becuase you have to measure to the lowest possible point on this graduated cylinder which is between 27 ml and 28 ml


*note- Mr. Paek said that when measuring only measure to the closest you can so if its between 41 and 43 just guess 42 and not 42.5 because you dont really know that its 42.5 your just adding in extra numbers that you really dont need. So keep it simple when your measuring dont just try to make yourslef look smarter becuase its not going to work.


And now for some very punny chemistry jokes...


Two atoms are walking down the street.
Says one atom to the other, "Hey! I think I lost an electron!"
The other says, "Are you sure??"
"Yes, I'm positive!"


A neutron walks into a restaurant and orders a couple of cokes. As she is about to leave, she asks the waiter how much she owes. The waiter replies, "For you, No Charge!!!"


A small piece of ice which lived in a test tube fell in love with a Bunsen burner. "Bunsen! my flame! I melt whenever I see you" said the ice. The Bunsen burner replied :"It's just a phase you're going through".


Source:http://www.coolscience.org/CoolScience/CoolJokes/ChemJokes.htm


ohh and before i forget... Other jamie your the next blogger, sorry! (think of it this way your getting it over with sooner rather than later!)


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