Monday, December 07, 2009

Leaf Chromatography

We’ve tried this one a couple of times – the third time we had success!

The object is to draw the colors of the chlorophyll from the leaves, and to have the colors separate via chromatography. Easy enough, right?
If you have access to any leaves, you can try this one out.

We used small glass jars, strips cut from a coffee filter, isopropyl alcohol, a variety of leaves, scissors, paper, and a pan.

We gathered different (fall) leaves – catnip, rose (red and green), raspberry, and evergreen.

We tore them into smallish bits,

placed them in baby food jars, then mashed them a bit with a pestle. We marked on a piece of paper what was what.

The first time (a couple of years ago) we tried this experiment, we used spinach, and couldn’t get any colors onto our chromatogram (filter paper).
The second time (a few weeks ago), we found it very difficult to keep the water hot, and didn’t have satisfactory markings, either.
So the third time, we placed our jars in a pan of shallow water, and heated the jars on the lowest temperature for several minutes.

Warning: Heating alcohol is extremely risky! Any kind of alcohol is highly flammable. While this process worked for us, and we were safe, please consider just tearing the leaves, then placing them in jars for a day or so, shaking periodically.

When the alcohol was satisfactorily tinted, we sat them on the counter (in the same order, since they were not marked), and put in our strips of filter paper.

We put them on our shelves (where our experiments-in-progress always go) and let them sit – it might have been overnight.


I had supposed that the greener leaves would produce the most colors, as I figured they were the healthiest and the most “alive”.
That wasn’t the case, actually.
The rose leaves that I crushed that were red actually had the most variety of color,

and the evergreen had the most variety of green color.

The (pretty dried) red raspberry leaf had the least color – which I expected, because it was the thinnest, and very near falling off the cane.

Very interesting!

We got this experiment (with explanations of leaves changing colors) here, at Science Made Simple.

Thorough explanations of the matter inside the chlorophyll can be found here, at WebExhibits.

We’ll definitely be doing this in spring and summer to compare with the results of our autumn leaves!

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