Whoosh Bottle, take 1

Tom Kuntzleman | Thu, 02/13/2014 - 09:17

My students and I intend to use a high-speed camera to film a variety of chemistry experiments in slow motion. The first reaction we have decided to film is the “Whoosh Bottle”. You can read more about this particular experiment in an article in Journal of Chemical Education here. NOTE: Only trained chemists familiar with the hazards associated with this demonstration should perform it. Before discussing the filming of this reaction, we’d like to extend an invitation to the ChemEd Xchange community to suggest various chemistry experiments to film with our high speed camera. There are several chemical reactions that we plan on filming in slow motion (especially the thermite reaction!), but I am sure that some of you have some interesting ideas as well.

Okay, now back to the Whoosh Bottle. In this classic chemistry demonstration, a small volume of alcohol (usually methanol, ethanol or isopropanol) is placed into a plastic container such as a gallon milk jug or 2L soda bottle. We used methanol as the fuel in our experiments. The container is sealed, and the bottle is shaken to allow alcohol vapor to fill the container. After shaking, the container is placed on the floor, the seal is removed and the vapor is ignited. What happens next? Check out the video below to find out!

After viewing these videos we decided to repeat the experiment but focus more on the flames being ejected from the Whoosh Bottle:

Viewing the Whoosh Bottle reaction in slow motion has brought a number of questions and thoughts to mind. For example, we are wondering what similarities and differences we will see if we use isopropanol instead of methanol as the fuel for the Whoosh Bottle. This is because isopropanol tends to combust differently than methanol. You can learn more about the differences in the combustion of these alcohols in the video below.

Now that you know a bit more about incomplete and complete combustion, view the Whoosh Bottle videos again. You should be able to differentiate regions of the flame where complete or incomplete combustion is taking place.

What questions do you have about the Whoosh Bottle after viewing it in slow motion? Do you have any ideas for Whoosh Bottle experiments to film in slow motion? Do you have any suggestions for chemistry demonstrations other than the Whoosh Bottle to film in slow motion?

Thanks go out to Kamal Ghazi and Nathan Ford for helping to film the Whoosh Bottle experiment in slow motion.

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Demonstration videos presented here are not meant as tools to teach chemical demonstration techniques. They are meant as a tool for classroom use. The demonstrations may present safety hazards or show phenomena that are difficult for an entire class to observe in a live demonstration.

Those performing the demonstrations shown in this video have been trained and adhere to best safety practices.

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Comments 14

Slow motion combustion of ethanol

Hi Tom, the combustion reaction looks really fantastic and in so much detail. It really shows how it builds up from that initial activation energy provided by the flame on a stick to the release of so much energy. Here in London, England we have been doing similar experiments and demonstrations. A few weeks back one of our students filmed a few with a high speed camera.

These are the results:

http://www.youtube.com/watch?v=lOCYOdJ5xjU

I'm sorry I do not know yet how to insert the video only so I have to post the link where you can find a more detailed explanation below in the description area.

More to follow soon.

Thanks,

Andres

Andres:

Andres:

Thanks for sharing your video. The experiments in your video are beautiful! In both your ethanol rocket and our whoosh bottle, it looks as though some alcohol in the liquid phase is ejected from the bottles. This liquid phase alcohol is not initially ignited, but does seem to ignite once it gets hot enough. Very interesting!

slow mo science link

Great videos and ones that are sure to get students' attention/interest.

I was approached last year by the Online Discovery Channel "Distort" to comment on their slow motion video of the thermite reaction (please use lots of caution with this demo). Their video is quite spectacular.

[Editors note:] This comment has been edited to remove references to resources that are no longer found at the link provided.]

thermite video

Larry, thank you for sharing your video. It was very cool to see you in the interview. I did not know that oxygen gas was produced in the thermite reaction. I always thought the reaction was simply:

Al(s) + Fe2O3 (s) --> Fe (l) + Al2O3 (s).

Is the oxygen gas produced an intermediate in the reaction or is it a product?

High-speed video

The detail on your video was beautiful. I would love to see a high-speed video of the Mentos in Diet Coke experiment. It goes so fast that it is impossible to see what's happening. It might be messy, however!

Kathy Shade

Diet Coke / Mentos

Great idea, Kathy! What would you think if we used Sprite instead of Diet Coke? We might be able to get a little better view of what is going on without the brown color of the cola getting in the way.

Slow motion video

Tom, great videos. What in your experience, is a good choice of video camera for this kind of demonstration? I have used the 200 fps slow motion mode of a compact Canon camera with fair results. Which cameras are best?

Thanks

Camera type

Hi Ashely, thanks for commenting.

The camera we are using is a Phantom MIRO-EX2. It runs around $11,000 to $14000, depending upon lensing, lighting, etc. It is the entry level Phantom camera. We cobbled together money from various grants to acquire the money to purchase the equipment. I do not have any experience using any other type of camera, but I know there are less expensive options available.

Be careful how you show your demo- It just takes one mistake.

Tom,

I love demos and do at least three a week. But be careful as some demos when repeated could cause a disaster as the case in NYC recently. Each of the demos recorded I have done for over 20 years but you must make sure to take all safety precautions when recording the demo as an inexperienced teacher may try to replicate the demo and then there is a disaster. Example while lighting the whoosh bottle never hold the wooden splint with your hand. When lighting the water bottle be aware that the bottle can spin and the flame make go in different directions. The recordings are great. Vernier has some of them synched with data from their probes. Live demos are the best and I am sure teachers plan on replicating.

Thanks

Marsilio:

Thanks for your comments regarding some of the safety issues we all should consider when performing the Whoosh Bottle demonstration. I always light the bottle with a wooden splint at the end of a meterstick. Even from this distance, I can often feel a good deal of heat from the reaction. I'm glad you bring up the recent accidents that occured during demonstrations that involve methanol combustion, Deanna Cullen blogged about these incidents at http://www.chemedx.org/blog/lab-accidents and http://www.chemedx.org/blog/and-worst-happens-again.

Tom

whoosh bottle

I read an article not too long ago that said you should never use methanol for the whoosh bottle demo. It cited an accident - one of those terrible stories of students ending up with burns. I'm sorry that I cannot remember the source of the article, but in light of its history of causing accidents, shouldn't we be avoiding the use of methanol in our classrooms? The whoosh bottle works quite well with ethanol, but even that raises my blood pressure significantly every time we do it!

Bev

Whoosh Bottle Safety

Hi Bev:

Thanks for your concerns. I have gone back to edit the main article to indicate that only trained chemists familiar with the hazards associated with the demonstration should perform it. It turns out that some folks (including myself) think that using methanol as the fuel in the Whoosh Bottle is safer than using less volatile alcohols such as ethanol or isopropanol. See the author response letter at: http://pubs.acs.org/doi/pdf/10.1021/ed081p31.1 . I think this may be because when adding less volatile alcohols to the bottle, more of these alcohols remain unvaporized within the bottle. Upon ignition, the hot gases formed inside the bottle eject large amounts of unburnt, hot liquid alcohol from the bottle. When the hot liquid alcohol leaves the bottle, it comes into contact with a large amount of oxygen from the atmosphere. Of course the hot liquid is then ignited, producing a very large flame outside the bottle. We have filmed the Whoosh Bottle in slow motion using isopropanol (less volatile than both methanol and ethanol) and we almost always observe more liquid being ejected from the bottle and a subsequent larger flame. I think the take home message is regardless of which type of alcohol is used, one should make certain that there is little to no unvaporized liquid remaining in the bottle prior to ignition.

Whoosh bottle accidents

I have heard of bottles exploding, so I use a safety shield. If you forget to empty the excess alcohol before ignition, you might end up with a flame at the top of the bottle after the initial explosion. This can lead to some great discussion, but a ruined bottle. It might be a cool addition to your video. I also recommend only using bottles once because they can develop cracks that might be part of the reason some bottles have failed. I am glad to see the safety discussion here. Tom is creating a great service. I love to do live demonstrations, but I tend to avoid explosions and flames unless I feel completely confident in my knowledge and safety equipment. I wonder if a full speed video followed by a slow motion video would be a better alternative for some of these demonstrations that have caused injury.