1. November 8th, 2016
Bell Work
Why do you think studying ink would be valuable in forensic science?

2. Learning Objectives Content: I will know the basics of chromotagraphy.
Language: I will be able to show this by taking notes.

3. Applications in Forensic Science
Chromatography
Applications in Forensic Science
T. Trimpe

4. What is chromatography?
From Wikipedia ...
Chromatography (from Greek word for chromos for colour) is the collective term for a family of laboratory techniques for the separation of mixtures. It involves passing a mixture which contains the analyte through a stationary phase, which separates it from other molecules in the mixture and allows it to be isolated.
Which means ...
Chromatography is the physical separation of a mixture into its individual components.
We can use chromatography to separate the components of inks and dyes, such as those found in pens, markers, clothing, and even candy shells. Chromatography can also be used to separate the colored pigments in plants or used to determine the chemical composition of many substances.

5. Examples of Chromatography
Liquid Chromatography
Used to identify unknown plant pigments & other compounds.
Paper Chromatography
Can be used to separate the components of inks, dyes, plant compounds (chlorophyll), make-up, and many other substances
Thin-Layer Chromatography
Uses thin plastic or glass trays to identify the composition of pigments, chemicals, and other unknown substances.
Gas Chromatography
Used to determine the chemical composition of unknown substances, such as the different compounds in gasoline shown by each separate peak in the graph below.

6. Mixtures & Compounds
Mixture – Two or more substances that are mixed together, but not chemically combined.
Examples of mixtures ... Air – mixture of gases Bowl of cereal – mixture of cereal and milk Soda pop – mixture of soda syrup, water, and CO2 gas Fog –water suspended in air Kool-Aid – mixture of water, sugar, and flavor crystals
Examples of compounds ... Salt –Sodium and chlorine combined chemically Water –Hydrogen and oxygen combined chemically Carbon Dioxide – Carbon and oxygen combined chemically
Compounds – Two or more elements that are chemically combined.

7. Solutions
Solutions are mixtures in which one substance is dissolved in another.
Solutions have two parts: solute and solvent The solute is the substance that is dissolved. The solvent is the substance that does the dissolving
Identify the solute and solvent in each solution ...
Solution
Solute
Solvent
Lemonade
Soda pop
Ocean water
Solubility - A measure of how much of a given substance will dissolve in a liquid. A substance that does not dissolve in water is called insoluble. A substance that does dissolve in water is called soluble.

8. Paper Chromatography Lab
Obtain the supplies you’ll need.
1 Plastic Cup
1 plastic cup filled with water
4 pieces of filter paper
4 markers for testing
Stand with clamp
Timer
Choose one of the testing markers and draw a dot near the bottom of the filter paper - about ¼ inch from the bottom.
Pour a small amount of water into the large cup and then hang the paper strip in the cup.
Allow the water to move up the paper for 5 minutes and then remove the strip from the water. Hang it on the side of the table to dry.
Follow these directions to test the other pens.
Pencil
Filter Paper
Ink Mark
Tape – Label with marker

9. Complete the chart on your worksheet and then answer the questions.
What colors did your group observe in each of the black ink samples?
Do the colors occur in the same order on all the samples? Explain.
Did some ink samples not work? Why?

10. Chromatography Challenge
Work with your group to identify the pens used for each of the “Mystery Marks”.
1st – Test each of the Mystery Mark strips using the procedure from yesterday.
2nd – Compare your strips to the strips hanging in the classroom.
3rd – Write the number of the pen that you think matches each of the mystery marks in the space on your worksheet.
4th – Have your answers checked by the teacher. Keep trying until you are able to identify all 6 pens!
Pen A matches # _____ Pen D matches # _____
Pen B matches # _____ Pen E matches # _____
Pen C matches # _____ Pen F matches # _____

11. November 9th, 2016
Please take the next 5-10 minutes to silently write or draw about any feelings you may have about the election. We will not be sharing this out loud so you may write or draw whatever you like.
You will not have to turn this in. If you would like me to read it, I will.
If you have nothing to say, you may doodle or read silently.
Give your fellow classmates your respect remain silent during this time.
If you are disruptive, you will receive one warning and then a detention.

12. Complete the chart on your worksheet and then answer the questions.
What colors did your group observe in each of the black ink samples?
Do the colors occur in the same order on all the samples? Explain.
Did some ink samples not work? Why?

13. What is the Scientific Method?
What is it?
Why do we use it?

14. The Scientific Method
The scientific method is a process for experimentation that is used to explore observations and answer questions. 
Using this method allows for an experiment to be repeated so scientists can see if they can find similar or different results.
Sometime there are different versions of the scientific method.
The goal remains the same: to discover cause and effect relationships by asking questions, carefully gathering and examining the evidence, and seeing if all the available information can be combined in to a logical answer.

16. Vocabulary
Chromatography: The physical separation of a mixture into its individual components.
Chromatogram: a visible record (such as a series of colored bands, or a graph) showing the result of separation of the components of a mixture by chromatography.

17. Ask A Question
The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where?
Our question: Will all different types of black pens produce the same chromatograms?

18. Background Research
Rather than starting from scratch in putting together a plan for answering your question, you want to be a savvy scientist using library and Internet research to help you find the best way to do things and insure that you don't repeat mistakes from the past.
Think about our chromatography practice we performed yesterday. Make 3 observations about what you saw in the pens we ran yesterday.
Observations: Write at least 3 complete sentences!

19. Hypothesis
A hypothesis is an educated guess to your questions. Your hypothesis should answer this question: “Will all different types of black pens produce the same chromatograms?”
Sentence Starter:
I predict will happen because………

20. Test Hypothesis
Draw/Color each chromatogram below:

21. November 14th, 2016
Bell Work
Enter **SILENTLY** and **SILENTLY** work on your Bell Work.
Why do you think certain inks do not run as far on the filter paper?
**Hint: Think Solubility**
Why do you think certain colors run farther than others?
**Hint: Think Size**

22. Solutions
Solutions are mixtures in which one substance is dissolved in another.
Solutions have two parts: solute and solvent The solute is the substance that is dissolved. The solvent is the substance that does the dissolving
Identify the solute and solvent in each solution ...
Solution
Solute
Solvent
Lemonade
Soda pop
Ocean water
Solubility - A measure of how much of a given substance will dissolve in a liquid. A substance that does not dissolve in water is called insoluble. A substance that does dissolve in water is called soluble.

24. Scientific Analysis Do all of the strips look the same?
State your observations
Be specific in naming your pens and descriptions
I should be able to know what each strip looks like without looking at your sketch
Compare and Contrast

25. Scientific Analysis
4- Uses complete sentences to report back the findings from the investigation. This section will compare and contrast what each sample looked like. This section states any observations made about the investigation, such as any notable errors that might have affected the experiment.
3- Uses complete sentences to report back the findings from the investigation. This section will compare and contrast what some of the samples look like. This section states some observations made about the investigation.
2- Uses complete sentences to report back the findings from the investigation. This section will talk about what they saw on a basic level. Very few observations are made with basic detail.
1- No complete sentences are used and not all strips are mentioned in observations.

26. Conclusion Was your hypothesis correct? Should be like a CER.
Have a Claim, Evidence, and Reasoning
What does your experiment mean?
What does your experiment tell us about chromatography?
What does it tell us about pen color?
What does it tell us about pen brand/type?
Why do you think ink traveled or didn’t travel?
Solubility, solvents, solutes
What comes next?
What could you have done differently to have more accurate results?
What is an experiment that you could do next time? What would you change? What you test?

27. Conclusion
4- Uses complete sentences to explain if their hypothesis was correct or not. Uses the Claim, Evidence, Reasoning Model. Conclusion also clearly explains what the experiment means as well as all errors and what future experiments that could be done.
3- Uses complete sentences to explain if their hypothesis was correct or not. Uses the Claim, Evidence, Reasoning Model. Conclusion also mostly explains what the experiment means as well as some errors or future considerations.
2- Uses complete sentences to explain if their hypothesis was correct or not. Uses the Claim, Evidence, Reasoning Model to a certain degree. Conclusion somewhat explains what the experiment means as well as some errors or future considerations.
1- No complete sentences are used. Claim, Evidence, Reasoning is mostly ignored. Does not discuss what the experiment means or any other considerations.