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Name of Activity

Paper Chromatography

Author

STOMP

Keywords

chemistry, testing, chromatography, polarity, solvent

Subject

Miscellaneous

Grade Level

4, 5

Time

1 Hour

Brief Description

Students will use chromatography techniques to identify the writer of a secret note. One suspect is a computer scientist notorious for writing on whiteboards with Expo markers and the other is a ecologist notorious for labeling sample bottles with Sharpie markers.

Be sure to check with your teacher before bringing acetone into the classroom!!

Learning Goals:

introduce students to chromatography and chemical engineering

Materials:

paper cups – 2 per group (NOT POLYSTYRENE!) + extra for mess ups

strips of coffee filter paper (4 strips per group)+ extra for mess ups

One sharpie marker

One expo marker

water

acetone

Preparation:

Cut coffee filter paper into strips

Knowledge Background

Knowledge of the properties of water and acetone, knowledge of polar vs non polar and its influence on the results

Procedure

1. Introduce the problem (identifying the writer of the note) and brainstorm possible solutions. The solution we will be using today is testing the ink to see what type it is.

2. Split the students into groups (pairs ideally). Distribute the cups and filter paper.

3. Demonstrate how to label the filter paper and make sure every student does it right. Each paper should be labeled either SW, SA, EW, or EA, for sharpie-water, sharpie-acetone, expo-water, expo-acetone.

4. Have one person in the group take the sharpie filter papers and get them dotted with a sharpie marker from a teacher, and another person get the expo filter papers dotted with acetone.

5. Before distributing the water, instruct the students to dip only the water filter papers in the cup and to make sure the dot of ink doesn’t go below water level. Once you fill one of their two cups with about 1 centimeter of water, have them hold the paper until the ink stops traveling up the page or after about a minute. Have the students record the results.

6. Discuss the results and if any changes  occurred, and have the students suggest improvements to the test that would allow for better results. Go over the properties of acetone and water and their polarity and why changing the solvent might lead to better results.

7. Repeat step 5 with acetone, but before distributing the acetone, make it clear that acetone they should not put acetone in their mouths or inhale it directly, and that if anyone feels nauseous that they should tell you right away.

8. Compare the results with acetone from the results with water. Discuss why they might be different.

9. Cut off a strip of the note so that a bit of ink is near the bottom. Conduct step 5 with the note in front of the class. Observe the results and have the class make a conclusion about who wrote the note, based on their previous results. Talk about why testing is an important part of the redesign process, and what they could do to improve the test.

Extensions:

Adding extra solvents to test or extra markers as a challenge.

Modifications:

Using vinegar instead of acetone, or different markers (but make sure to test the markers with the solvents beforehand)

Name of Activity

Physical and Chemical Changes

Author

Tom DePalma, Yash Gurditta, Dan Weinstein

Keywords

chemistry, baking soda, vinegar, fun, experiment, space, mars, gas, ballon, propulsion

Subject

Miscellaneous

Grade Level

3, 4, 5, 6

Time

1 Hour

Brief Description

The activity is structured like a traditional classroom experiment and is used to teach the difference between physical and chemical reactions.

Learning Goals:

Introduce students to basic principles of chemistry–Teach students how to analyze and interpret observations and use data to solve problems

Materials:

water, vinegar, baking soda, corn starch, table salt, plastic cups, large plastic bins, paper towels, newspaper

Preparation:

Prepare samples of each substance for groups. Could prepare a table if you want but we found letting the kids design their own worked much better

Knowledge Background

Notes: The activity is somewhat messy so it s a good idea to notify the teacher in advance.  The kids have a hard time understanding the difference between the two types of reactions.  Discussion after the experiment and before the challenge task it definitely the most important part of the activity.

 

Background:

Vinegar and baking soda react to produce a gas

Alka seltzer and water/vinegar react to for gas

corn starch and water/vinegar form a goopy solution

table salt and water/vinegar–>dissolves

Procedure

To start the class, we discussed the difference between physical and chemical changes. The group provided examples of both and we wrote them on the board. Using the list, we were able to create a spirit list of characteristics to be used in determining if an event results in a physical or chemical change.

The activity is structured like a traditional classroom experiment. The students were split into groups of three and were given these materials: Baking soda, table salt, alka seltzer, corn starch, water and vinegar. Their task was to mix each of the sold substances with the two liquids and record their observations. Each group was told to design a table to record their observations.

Each table was covered in newspaper to keep the areas clean and the experiments were performed in plastic NXT bins. Each group was given a pre-allocated amount of each substance and told that was all they would be receiving.

The reactions and the observations took about 20 minutes. After completing this, the group came together and the results were discussed.

The next part of the activity can be done by each group individually if time allows. We ran out of time so it was done as a class demonstration. The class observed that some of the reactions lead to the production of gas. We gave the class the challenge of blowing up the balloon using one of the reactions. They chose what materials would be best and we put the solid in the ballon and the liquid in a plastic water bottle. The balloon was stretched over the neck of the bottle and the solid was dumped into the liquid. The balloon inflated.

We connected this result back to our unit (trip to mars). We explained that gases can create force and are used to propel rockets upward.

Umbrella Unit/Curriculum (if applicable)

Trip to Mars

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