explain chromatography to 5th graders

[jzt]

I volunteered for the "career day" at my daughter's school. Now I have 15 mintutes to tell the 5th graders about what I do, how it is done, and why it is important. I'd like your suggestions on how to make this a success. With only 15 minutes, I am not sure if I can do any real demonstration (even with paper chromatography). I think the next best thing would be some cool graphic/diagrams I can print out to show the students.

all suggestions are appreciated!

[Noser222]

I think a small TLC plate, say 5 inches long, with some colored dyes could work in 15 minutes. You should have plenty of time to explain what's going on while it's running. You could make 2 or 3 spots with different colored dyes and then spot a mixture next to them and show how it separates them.

[Noser222]

Of course, 15 minutes is also plenty of time to do few UPLC runs, so roll one in there

[skunked_once]

I think this web site may help you out.
http://www.itsjustabox.com/Sciencefair.htm
Real life uses of chromatography: medicine,
clinical tests, pollution monitoring, food analysis.
Good luck, be cool, and expect questions.

[jzt]

Thank you both for your suggestions. My main issue is the 15 minutes time limit. If possible, I'd like to avoid bringing in organic solvents in the classroom. I did check the http://www.itsjustabox.com/Sciencefair.htm website before posting. Many of the links there do no work anymore, and most experiments mentioned can't be done in 15 minutes. Thanks anyway.

[skunked_once]

Try this link. I use this in my introductory chemistry class with a plastic-backed silica TLC strip in a 100-mL graduated cyinder and 1% acetic acid as the mobile phase. http://science.csustan.edu/nhuy/chem1002/mrsketch.htm
Use the black mrsketch marker for a rainbow of colors. There will be enough color separation in the 15 minutes for the students to see the process in action. You can do the explanation while the colors are developing.

[GOM]

Hi jzt,

My apologies, I need to update the itsjustabox site for the broken links.

To make some general observations (I apologise if some of them seem obvious)

1. Know your audience e.g. have they already been introduced to paper chromatography? I assume that 5th grade is 10-11 year old?

2. Assume that your 15 minutes will only be 10mins! It is a challenge to fit it in this time so the main points to get them to go away with are that it is important because
a) Most things are mixtures
b) chromatography is a way of separating mixtures
c) if we can do this them we can identify each part of the mixture and
d) measure how much there is of each
e) areas where chromatography is important to their lives

3. You will need some visual aids/props to raise interest. It is possible to do a simple ink/paper separation in this time - however, if you do go this route then practise it to make sure it will work in the time. Have a back up one that has already been done in case it fails. Remember - it only has to start separating the colours.

4. Be wary of passing around props - they can distract from your talk.

5. Is a projector available or would setting this up take up your talk time?

6. One method that I have used in the past is to analyse somebody's perfume or deodorant perfume by GC beforehand then show the chromatogram to show the complexity. I also brought in three of the components for the children to smell.

7. Linking back to 2 and 3, I would have a box of household products and bring each one out as an example of how the use of chromatography is covered. e.g perfume, cola, honey, syrup, model plane. Ask them first how it might be important - allow two answers then tell them. Don't reveal them all at once. Bringing out a bottle of "BLOOD !" then correcting yourself to say ketchup can raise a smile at that age.

8. Sometimes you can start off the talk with some of the props in a "what links these?" kind of way. Here you can use items that are as mad as you can find - e.g. dead fish (slap it on the desk), balloon ( burst it with a pin), rubber chicken - now you've got their interest .

9. Practise and time yourself several times to get it right.

You can the balance right with everyone having fun and at the end of it they can walk away having learnt something ( that your daughter has a weird dad )

you can email me at ralph.calvert@gmail.com if you want to discuss it in more detail.

Regards,

Ralph

[JJG]

A fun demo I have done is to separate food coloring from different Kool-Aid flavors using a C18 SPE cartidge. This works well as a hands-on project with several stations. Everyone gets to pick their flavor and find out which colors are in it. You can visually see the separation of colors, and even collect each color in a small beaker. Takes about 5 minutes to run though, but about 15 minutes if you demostrate it first, and then others perform the task. Might be though to fit it in timewise, but figured I would suggest it.

[gcguy]

I do a set of presentations every year for the RSC to 14-16 year old about what science means to them and what sort of work science involves. We do five 30 min presentations a day for three days so it is pretty tough. The biggest issue we have is dealing with the kids attension span, I don't think adolesent kids can concentrate for more than 5 mins at a time!

Try to keep it interesting and try to interact with the kids, ask them questions. You could make a competition out of the ink chromatography.."how many colours are in the ink?" give a small prize to the winner.

Best of luck.

GCguy

[jzt]

Thank you all for your wonderful suggestions, I guess people are coming back to work after the holidays. I knew I posted the question in the right place.

Ralph,

You website is still very helpful, especially in explaining how it works what it is useful for. I didn’t mean to make you feel bad about it.

I combined the suggestions and information I gathered from the internet, and tried a few runs in my office yesterday. I took some filter paper from the lab (I don’t own any coffee filter paper, I prefer tea), and used water as the mobile phase to separate colors in markers. Cut the filter paper into rectangular pieces. Use the markers to make a tiny spot about 1 cm from the bottom. Fold the paper once so it can stand up on its own. Then just let it sit in a flat dish with water in it (< 0.5 cm depth). It takes 5 -7 minutes for each run (about 4 cm). I tried it with my kids last night. First I asked them which colors they thought were from different basic colors. Of course they gave me green, orange, purple, etc. With plain water, the Accent green highlighter spot separated nicely into yellow and blue, but the separation with the orange, purple and teal was not very good (we talked about separation). Interestingly, the yellow separated from the green marker did not match the yellow coming out of the yellow marker spot of the same brand. We gathered yellow markers from different brands and ran them side by side and found one that matched the yellow from the green marker (and we talked about identification). They got really excited and brought out all their Crayola markers. They were surprised and really intrigued to see the rainbow of colors coming out of the brown and black spots. We tried salt water, vinegar, and different combinations of these two additives. Salt water worked the best. Vinegar actually made one of the yellow spot disappeared (color vs. pH). We ended up with all these colorful paper strips on our kitchen table. My 10-year-old asked me: “can I be a chemist too?â€

[GOM]

Hi,

No problem, you have actually done me a favour about the website needing updating.

I'm glad that you are making progress - let us know how the talk goes.

To JJG - I really like your cartridge approach. Do you precondition with methanol then water? Do you elute with water? I suppose you could reduce the time even more (for a demo) by putting in the plunger from a disposable 2.5ml syringe and pushing the solvent through very gently.

Regards,

Ralph

[Uwe Neue]

I am sorry that I did not see this question before...

I have done the paper chromatography with the felt tip pens. If you have different black pens with different color compositions, you can attach to the demo a detective story: how the pen that wrote the secret note can be identified...

The Kool-Aid mix separation can be very interesting, plus it is fast. The Kool-Aid contains two dyes, Red Dye # 40 and Blue Dye #1. The separation can be done with a Sep-Pak C18 cartridge. You can buy a kit with instructions on how to do this demo from Waters, part number WAT088253. It is also described in my book on one of the last pages. Essentially you work with IPA/water mixes. You start off with activating the cartridge with 70% IPA, then water. Then you load the Kool-Aid, wash with water, leaving the purple band behind. With 6.5% IPA you now elute the red dye, followed by an elution of the blue dye with 35% IPA. What remains behind is the colorless flavor, and it is up to you if you want to elute it with 70% IPA and have the kids smell the flavor in the IPA. Even without the smelling exercise, it is impressive to the kids to separate the purple into blue and red.

[jzt]

I am happy to report that the career day presentation went very well. I was able to use PowerPoint presentation since there are computers and a LCD projector in the classroom. I put the word “chromatographyâ€

[DR]

[quote="jzt"]“How much money could I make if I were to be a chromatographer?â€

[jzt]

In my answer to that question, I gave a somewhat higher starting salary (but $50K is not much in California!), and leave the upper end open by saying it could be well over $100K. Of course I omitted the qualifier "if you go into management, QA, regulatory affairs or other functions". Later I checked my daughter's homework, that question is on the form the students have to fill out. I am kind of concerned how the numbers under Chromatographer will compare to the other professions listed on the form.

Of course we are in this profession because we love it, not for the money, right?