Volcano Experiment - Feedback from our visitors

Hi, Was on your site with my first grade son and wanted to give you a really
easy way for elementary aged kids to do this experiment by themselves.

Dishwashing Soap
Baking Soda
Red Food Coloring
Long Slender Jar
Warm Water
Modeling Clay

Make a mountain of sand on the Cardboard. In the Slender Jar place 1
tsp of baking soda. Add warm water filling the jar about 3/4 full.
Shake to mix the soda and water. Add 3 drops of dishwashing soap and
several drops of food coloring. Shake again. Cover with a ball of the
modeling clay. Stick the jar down in the mountain of sand. Remove the
clay and add 2 tsp of vinegar. This will cause a small eruption.
Perfectly safe and easy enough for your first graders to present to
their class without assistance.Thank you, Deirdre Wulf

The volcano experiment using ammonium dichromate looked great, but, how safe is it-does it produce any poisonous gases, fumes? Also, where can one acquire ammonium dichromate? I'm interested in doing this with the afterschool science class I teach, but am concerned that it might not be appropriate/safe for 3 and 4th graders.
-Sue Pike

No, there are no hazardous fumes. The demonstration can be conducted indoors. You should wash your hands after handling the ammonium dichromate and the chromic oxide ash. There's some controversy about the hazards of chromium compounds - possibly carcinogenic, I think. That's about all I know on the
hazards subject, but I and many people have been doing this demo for years.

The "fumes" from ammonium dichromate decomposition is nitrogen gas, not toxic. And clearly the chromic oxide ash is far less toxic than the dichromate. Please do not ban this experiment, kids love it and it depicts fundamental aspects of chemistry.
Mike Aucutt

you're so cool I have a report to do and you really helped me!!

Mr. Rich,
I found this experiment while perusing the Josie True website (http://www.josietrue.com/activities/volcano.htm). It is a classic and very cool. The thermite experiment is also exciting and dramatic. Unfortunately, the green chromic acid product is a toxic waste that
requires special handling (it should not be just thrown away in the trash). Using it as you describe to prepare a thermite reaction is dangerous for children (well, anybody, really, but the website leads one to believe an 11-year old could reasonably be doing this.) Goggles and gloves are not even mentioned!
More frightening is that the site leads one to believe there is no real danger in mixing aluminum and potassium perchlorate. As you know, potassium perchlorate is a powerful oxidant that will react with almost anything that can be oxidized (almost any organic material for instance). This is something that should only be handled by trained people using proper equipment and procedures. It is definitely NOT an experiment that can/should be done at home!
Sorry to sound off. But there are enough dangerous places on the web without adding to it on what promises to be a wonderful site for girls to learn science and math.
Bill Harwood
Associate Professor, Science Education
Indiana University

Yes, you're absolutely right. Josie's use of the experiment really changes the audience from what I intended. I shall provide warnings. Thanks!
[NOTE: The volcano experiment page has been modified to remove the thermite reaction.

Thank you for responding so positively! It is surprising where one's information can end up. I hope you won't mind one more suggestion. If you keep this item I recommend that you break it up into two parts--the volcano part and the thermite part. Also, please consider removing the "iron skillet" suggestion. I have this vivid image of someone putting chromic acid onto grandma's iron skillet and heating, then cleaning the skillet in the sink (and who knows how well or poorly!). It is then used for cooking and the family ends up eating chromium laced food... It is not a comfortable image for me. You seem like a good person (I approve of folks like you and me that go out and excite kids about science). Thermite is a reaction for pros like yourself and others who can properly handle and dispose of dangerous and toxic compounds. And, of course, one never mixes food with specialty chemicals like these!
Take care and thanks again for giving me a hearing. I appreciate it.
Bill Harwood
Associate Professor, Science Education
Indiana University

I am concerned at your use of ammonium dichromate . It is not allowed in New Zealand as the fumes are very carcinogenic.

Do you have a reference on that? I looked it up one time, and found references for chromium, but not ammonium dichromate.

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Updated 20 October 2008