friday, 11/19/2010

Friday, 11/19/2010

• Objective: Chromatography Lab!

Get your folder and get readyto start the

TIMED BELLRINGER QUESTION.

BELL RINGER

1. How do plants get energy?

2. Why do leaves change colors in the fall?

5 MINUTES

BELL RINGER

1. How do plants get energy?

2. Why do leaves change colors in the fall?

4 MINUTES

BELL RINGER

1. How do plants get energy?

2. Why do leaves change colors in the fall?

3 MINUTES

BELL RINGER

1. How do plants get energy?

2. Why do leaves change colors in the fall?

2 MINUTES

BELL RINGER

1. How do plants get energy?

2. Why do leaves change colors in the fall?

1 MINUTE

TIME’S UP!!!!!

Paper Chromatography

Lab

What is Chromatography?Chromatography is a technique for separating mixtures into their components in order to analyze, identify, purify, and/or quantify the mixture or components.

Separate

• Analyze• Identify• Purify• Quantify

ComponentsMixture

Uses for Chromatography

Chromatography is used by scientists to:

• Analyze – examine a mixture, its components, and their relations to one another• Identify – determine the identity of a mixture or components based on known components• Purify – separate components in order to isolate one of interest for further study• Quantify – determine the amount of the a mixture and/or the components present in the sample

Illustration of Chromatography

Mixture Components

Separation

Uses for ChromatographyReal-life examples of uses for chromatography:

• Pharmaceutical Company – determine amount of each chemical found in new product• Hospital – detect blood or alcohol levels in a patient’s blood stream• Law Enforcement – to compare a sample found at a crime scene to samples from suspects• Environmental Agency – determine the level of pollutants in the water supply• Manufacturing Plant – to purify a chemical needed to make a product

Overview of the Experiment

Purpose: • To explain the relationship between pigments

and photosynthesis.• To predict which pigment colors would be best

for photosynthesis.

• 100 mL beaker• Isopropyl Alcohol (10 mL)• Chromatography paper

strip • Spinach leaf solution

– Red leaf lettuce solution• Disposable Pipette• Pencil• Ruler• Scissors• Tape

Materials List

Preparing the Chromatography Strips

2. Starting at the line, taper the bottom of the paper with scissors.

3. Place 1-2 drops of the spinach leaf solution on the starting line and allow to dry

1. Draw a line 1.5 cm above the bottom edge of the strip with the pencil

Developing the Chromatograms

• Place the strip in the beaker• Make sure the solution does

not come above the drop on your start line

• Fold the top of the strip over your beaker and tape to keep in place

• Let strips develop for approximately 15 minutes

• Remove the strips and let them dry

• Use the table on your lab handout to analyze your chromatography strip

• Answer the analysis questions in your lab notebook

RESULTS

Debrief/Wrap UpKnowledge of Inquiry

*Scientific investigation begin with a problem but don’t necessarily test a hypothesis

*There is no single scientific method*Inquiry procedures are guided by a

question*All scientists performing the same

procedures may not get the same results*Inquiry procedures can influence results*Conclusions must be consistent with the

data*Scientific data is not the same as scientific

evidence*Explanations are developed from the data

and what is known

NOS*Tentativeness*Creativity*Observation vs. Inference*Subjectivity*Theory and law*Socially/culturally

embedded*Empircally based

Suggestions/Comments: