Biology 9/19 HW/RD

Here is the guide sheet for the Measurement lab.

Measurement Lab

Title:  Hint, be descriptive and to the point

Question:  How can OHS measuring devices be used by students to accurately measure the density of water?

Hypothesis:  Hint, your answer must include the independent and dependent variables you will test to support or refute your question.

Test:  Hint:  Density = Mass/Volume.

Materials:

(1) P-1000 micropipette, (3) Reaction tubes, box of blue tips, (1) 1000mL plastic waste beaker, (1) metric balance, supply of dH₂0 in (1) small glass beaker, paper towels, safety equipment-eyewear and aprons…….

Procedures:  Hints, Make sure your final procedures include labeled diagrams

1. for the Rd just do your best to describe how to use each material in a logical order  
2. for a diagram show how the P-1000 window will read for each different volume extraction and how you will use the balance.
3. you will conduct at least of 3 trials of data collection for each member of your group
4. you will need to empty rxn tubes of any trace of water and re use-them,

Data Table: 

(example:  Remember that you need room for at least 9 trials!!)

Measurer	Mass of empty tube	Mass of tube and H2O	Mass of H2O	Volume of H2O	Calculated H2O density

DON’T forget to record observations of data collection

Analysis: 

This section should include a graph of the data (mass on the y-axis & volume on the x-axis), the formula for density, show at least one example of the math you did when calculating density and answer the following questions. Hint you will want to convert measured μL – mL to answer the questions

1. Check your accuracy for the measurement lab; calculate percent error for the average of your three trials?  

Percent error = (measured average density – 1g/ml)  . 100%

                1g/ml

2. What is the accuracy for the average of all trials by your group?
3. Which measuring device is most accurate?  Explain your answer

4. E.C.  graph volume  -vs- mass For water for all 9 trials. 

Conclusion:(This should be at least 3 paragraphs)

Don’t forget to explain what happened?  Restate your question and hypothesis and why you thought it was the best guess.  What do you know about the answer to the question?  How does the data support your answers? i.e.use numeric comparisons to support your answers!  How did human error influence your data?  How could you further/redo this experiment for more accurate results?  What is the social context for this lab?