Overview
Today we started off class of by sharing our opinions about the Observation Lab, then took a small quiz on Independent and Dependent variables. In addition, Mrs. Friedmann gave a presentation on matter.
What did you think of the Observation Lab... here's what the class said
-fun :)
- interesting to mix chemicals
- involved a lot of independent work, unlike last year
- had to work quickly in the lab due to limited amount of time
- stations were crowded
- took longer time to clean up (Mrs. Friedmann said leave about 5 min at the end of labs to clean up)
***Mrs. Friedmann also said that you do not have to bring your spiral lab notebook to record your "final" data in class. You may do that work at home and record your rough observations in your notebook in class.
Variables and Experimental Design
Quick Review:
-Independent variable = what "I" (the experimenter changes).
-Dependent Variable = what is observed and measured. It is the result that is caused by changes in the independent variable. Dependent variable must be measurable or qualitative data.
- Qualitative data= no numbers
- Quantitative data= numbers
Controlled Variable(s)= everything else I try to keep the same from trial to trial.
Today:
Utilizing the information listed above we completed a worksheet, in which we had to identify the 3 variables in a scenario. After completing the worksheet we took a small quiz.
How Do Chemist Classify Matter?
In class, Mrs. Friedmann gave a presentation on how matter is classified. The notes accompanying the presentation can be found on Moodle. Here are the additional notes Mrs. Friedmann wrote on the board during the presentation.
Chemistry= the study of MATTER
-Matter can be divided into 2 categories: Pure Substances and Mixtures
- Pure Substances can be further divided into Elements and Compound
PURE SUBSTANCES
Elements
- About 110 of these
- Can't be broken down into simpler form
- All atoms of one element are same (in certain
key ways)
Compound
-Many types of these
- Different elements are chemically combined by
bonds( can be considered as "glue" for now)
- Mixtures can be further divided into Homogeneous and Heterogeneous
MIXTURES (physically combined, not combined by bonds)
Homogeneous
- All parts of the mixture have the same parts
EX: Where ever you take a sample from a sugar mixed
coffee it will have same amount of sugar and coffee.
Heterogeneous
- One part of the mixture may have different amount of
substance than another part.
EX: If you take a sample of sand from one part of the beach
it will be different from the other part of the beach.
Homework:
To answer this question...
-Suppose I make a taco salad for lunch. Can the salad be best described as Compound, Homogeneous mixture, or Heterogeneous mixture. Why?
- WebAssign safety quiz was due by 11:59 today
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| Beach sand |
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| Coffee |
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| Small text: That isn't dark matter sir --- you forgot to take off the lens cap |
The next scribe post author is Janet Nwosisi
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