Online Performance Test for the Energy Benchmark

By Steve StultzJ.C. Harmon High School

Kansas City, KS School DistrictJuly, 2008

*Created as part of the NSF-funded Research Experiences for Teachers program at the Center for Environmentally Beneficial Catalysis, located at the University of Kansas

Introduction

• When scientists make biodiesel they measure something called the acid number.

• The acid number is used to determine the level of free fatty acids, processing acids or degradation by-products in the biodiesel.

• These acid by-products are not normally found in petroleum-derived diesel.

Why Test for Acid Number?

High acid numbers increase the likelihood of:

• Fueling system deposits

• Corrosion

• Engine deposits, particularly in the fuel injectors.

• Plugged filters

ScenarioImagine that you’re a scientist

You work for Dr. Williams at the University of Kansas

Your job is to determine the acid number of biodiesel samples

How Do You Measure Acid Number?

• The machine drops small amounts of a base called potassium hydroxide (KOH) into the sample

• After each drop, the machine measures the pH

• When pH 11 is reached, it stops adding base

• The amount of base needed to reach pH 11 indicates how much acid by-products are in the sample

• This value is called the acid number

With an automatic acid titration machine, of course!

Your Job

You will test 6 biodiesel samples.

You will compare your results to a standard acid number to determine which sample is the best.

Start Collecting Data

Create a data table on a piece of paper to keep track of your information.

Your table should include the sample number, thesample description and the resulting acid number inmgKOH/g.

You will watch videos to learn about each sample and then collect your own data.

Sample 1

Click on the link below for the contents of sample one. Describe sample 1 on your data table. http://www.teachertube.com/view_video.php?viewkey=965bdbb4234b23d3dbea

Results for Sample 1

The acid # atpH 11 was0.297mgKOH/g.Record on yourdata table.

Sample 2

Click on the link below for the contents of sample one. Describe sample 2 on your data table.

http://www.teachertube.com/view_video.php?viewkey=2be891d8c90da8431be1

Results Sample 2

The acid # atpH 11 was0.38mgKOH/g.Record on yourData table.

Sample 3

Click on the link below for the contents of sample one. Describe sample 3 on your data table.

http://www.teachertube.com/view_video.php?viewkey=47dba2bc98b9558aa20c

Results for Sample 3

The acid # atpH 11 was0.119mgKOH/g.Record on yourData table.

Sample 4

Click on the link below for the contents of sample one. Describe sample 4 on your data table.http://www.teachertube.com/view_video.php?viewkey=1c566de8d91cb6fe6ca5

Results for Sample 4

The acid # atpH 11 was0.097mgKOH/g.Record on yourData table.

Sample 5

Click on the link below for the contents of sample one. Describe sample 5 on your data table.

http://www.teachertube.com/view_video.php?viewkey=458e3299ad2a1f4e7c2b

Results for Sample 5

The acid # atpH 11 was0.097mgKOH/g.Record on yourData table.

Sample 6

Click on the link below for the contents of sample one. Describe sample 6 on your data table.

http://www.teachertube.com/view_video.php?viewkey=032281c7367aea1f0d1c

Results for Sample 6

The acid # atpH 11 was0.103mgKOH/g.Record on yourData table.

Graph Your Data

• Create a graph to analyze your results– You must choose the best type of graph for

your data

• Graph should include sample # verses acid # in mgKOH/g.

• Make sure to properly label each axis and title your graph.

Analyze Your Data

So, you have just tested the acid number for 6 biodiesel samples.

Now you want to determine which sample is the best fuel for an engine.

How do you know which sample is the best?

For biodiesel to be safe in an engine, the acid number should be less than 0.5 milligrams of base per gram of sample (0.5 mg KOH/g).

The lower the acid number, the better the fuel.

Questions1. Which sample had the highest acid number?2. Which sample would most likely increase fueling

system deposits?3. Which sample would be least likely to corrode the fuel injectors?

Turn in your graph and questions and answers.

Rubric for Scoring Science Performance Assessment:

Inquiry 1.1.3

Distinguished

(Wow!) (5)

Basic

(Acceptable) (3)

Unsatisfactory

(Redo) (1)

Graphing: The correct graph format is chosen.

The data is represented accurately and in the correct fashion.

The graph is neat and easily interpreted.

Axes are properly labeled and have units.

Independent and dependent variables are on the proper axis

A good title is present and the communication of data through the graph is accurate.

The correct graph format is chosen.

The data is represented accurately and in the correct fashion. One data point may be incorrectly graphed

Some sloppiness can be found that doesn’t prohibit interpreting the data.

Axes are properly labeled and have units

A title is missing but the general communication of data through the graph is accurate.

The incorrect graph format has been chosen and/or

the graph is so poorly made that the communication of the data is lost

Axes labels are incorrect, missing or do not have units

Questions: All 3 questions are answered correctly.

Two questions are answered correctly.

One question is answered correctly.

Grading Rubric