Science Buddies: "Ask an Expert"

I am working on a 6th grade science project and I need your help please.

These are the instructions - "Prepare a strong gelatin solution with gelatin powder from your grocery store. Then dilute it with ten parts water and boil up the Universal Indicator. This is in an alcoholic solution, and adding water and heating it will dilute and evaporate some of the alcohol, which might otherwise stop the gelatin setting. Finally add the two solutions together and pour into glass. You should balance the amount of indicator added so that the color is not too dark a green. Let the gel set.

Now insert two pieces of carbon rod, one on either side of the gel. Now apply a DC voltage from a battery to the two electrodes in the gel. 12V or 6v. Gas will be seen bubbling up at both ends at the higher voltages, forming a blob of color foam around the electrode. Hold about 2 min and remove, then remove the electrodes from gel. Now wait .......over a period of hours and days it will have rings of color out from the electrodes."

Now here is my questions, 1. How much universal Indicator do I use? 2. How do I connect the carbon rods to the battery? 3.What color should the gelatin be so that it doesn't conflict with the green universal indicator?

Any help would be greatly appreciated. C.D.

Hi Bojoco2,

I'm not familiar with this particular experiment, but this may help.

bojoco2 wrote: Now here is my questions, 1. How much universal Indicator do I use? 2. How do I connect the carbon rods to the battery? 3.What color should the gelatin be so that it doesn't conflict with the green universal indicator?

1 - Enough to be able to see the color clearly.

2 - The easiest method is probably with wires that have little metal clips on the end of them. They've usually called alligator clips, and you can buy them at an electronics store (like radio shack) for about 5 bucks for a pack of several clips. There are other possibilities if you have trouble obtaining them.

What kind of battery do you have? If it's a large battery, be especially careful not to short the positive and negative side together by connecting any metal across them, and never touch both the positive and negative connectors at the same time. It's also a good idea not to short out small batteries, except that it isn't likely to be dangerous to you.

3 - Try to get uncolored, unflavored gelatin powder. (Not "jello" or another flavored product.) It may be near baking goods.