You Can Learn a Lot from a Candle

Beginning in 1827, [Michael Faraday] began giving a series of public lectures at Christmas on various subjects. The “Christmas Lectures” continued for 19 years and became wildly popular with upper-class Londoners. [Bill Hammack], aka [The Engineer Guy], has taken on the task of presenting [Faraday]’s famous 1848 “The Chemical History of a Candle” lecture in a five-part video series that is a real treat.

We’ve only gotten through the first episode so far, but we really enjoyed it. The well-produced lectures are crisply delivered and filled with simple demonstrations that drive the main points home. [Bill] delivers more or less the original text of the lecture; some terminology gets an update, but by and large the Victorian flavor of the original material really comes through. Recognizing that this might not be everyone’s cup of tea, [Bill] and his colleagues provide alternate versions with a modern commentary audio track, as well as companion books with educational guides and student worksheets. This is a great resource for teachers, parents, and anyone looking to explore multiple scientific disciplines in a clear, approachable way.

If there were an award for the greatest scientist of all time, the short list would include [Faraday]. His discoveries and inventions in the fields of electricity, magnetism, chemistry, and physics spanned the first half of the 19th century and laid the foundation for the great advances that were to follow. That he could look into a simple candle flame and see so much is a testament to his genius, and that 150 years later we get to experience a little of what those lectures must have been like is a testament to [Bill Hammack]’s skill as an educator and a scientist.

19 thoughts on “You Can Learn a Lot from a Candle

  1. I love that they kept the original language, it makes it a little harder to understand, but much more interesting.

    Also, did I notice Faraday describing POV in 1848 that is used in so many hackaday projects today? (see 10:16 in the first video)

  2. Amazing when you consider that Faraday was not a scientist, but a bookbinder! He served a seven year apprenticeship after a most “rudimentary” education, and was entirely self taught. and at age 20 started to attend lectures at the Royal institution, many of them by Humphry Davy. He wrote up a series of notes on the lectures, bound them, and presented them to Davy, who was very impressed, and took Faraday on as an assistant, and to write up his notes as he had damaged his eyesight in a chemical explosion.Davy would later regret this as Faradays discoveries stole the limelight from him!

    1. I don’t think the body of scientific knowledge was what it was today.

      That is to say when there is not much to know being self taught is no big hindrance.

      1. I’ve been “doing electronics” for 30 years but I got my degree 7 years ago. I learned nothing in college, in fact I think I came out of school a little dimmer than I went in.

        There is A LOT to be said for being self taught – at least it made the classes a breeze because I already knew everything they attempted to teach us and was able to help others (including the instructors) out a bunch by elaborating when appropriate (no, those instructors didn’t hate me and certainly weren’t hostile to me, I wasn’t a “know it all prick” about it) And my grades reflected my knowledge going in.

        And the notion that it some how helped me in the employment world is also a big jug of snake oil I’d like to sell you too…
        The piece of paper got me the job and that’s about it. The skills I bring to the table are all from just being a logical human being – NOTHING of that came from school. Not one single bit of it. But if you want to buy into the idea that school somehow generates billions of well rounded employees to be every year, you can’t be helped in your stupidity. It’s terminal. Kindest regards to your family. R.I.P.

        I don’t think Faraday was “self taught” as far as his level of work, he made observations and then brought his hypotheses home via the scientific method, as one should do…
        There is plenty of room left for observation and the scientific method. People are still doing the same thing everyday, its just the huge, high dollar science stuff that gets noticed because sadly people don’t care when they have an android or iPhone to keep their attention. And there were A LOT of advances between then and now to bring us such things as the interwebs in our pockets.
        A lot of what makes people good or bad at science is their level of interest. The vast majority of people just simply don’t have the curiosity to be in a technical field let alone pay attention to the advances that ARE being made. Not that would help them contribute in such a way as a Faraday, Einstein, Hawking did / has anyway.

  3. So the claim is that the candle reaches 1400 ℃ ? That somehow doesn’t seem right, it’s orange and doesn’t have the right air mixture and fuel for such temps surely.

    I recently heard that ancient Egypt didn’t have steel knives that were melted because they could not reach the require temperature, so all steel knives were fabricated from cold forging metal meteorites, and of course were limited to the very top of the elite. which I mention because cast iron melts at about 1,375 ℃ , and the alleged temperature of the center of the candle flame in the first video would be higher.

    1. It is also blue if you look closely and from below up into the center of the flame. 1500C or so. The candle study is basically the first two or three days of class when I taught chemistry with everyone having candles and Pyrex tubes and clothes pins and 3×5 cards to get heat profiles, etc. A good variation is written up in the lab books for one of the popular chemistry texts and I wish I could remember which one. It was once quite common and today is fairly rare due to involving fire, which is too bad because it was probably the most memorable lab for the majority of students.

      1. I also lighted matches in candle flames, it took quite a time to ignite them for something that is suppose to be that hot.
        And people can extinguish them with their fingers.
        And the blue you can observe is at the underside, not where the video claim the highest temperature exists (top of the wick).
        And a butane torch only reaches 1300, which would be lower than a simple candle.

      2. Could you elaborate on the candle study lab exercise you referenced? You mentioned it like it’s well known, but I must have missed this in my chemistry classes. I’m perplexed as to how you’d use those elements to map the temperature of a flame.

        1. I have a copy of that lab book somewhere. I’ll see if I can find it. The lab is broken into quite a few steps and starts with simply overseeing a candle flame and drawing it and making as many specific observations as you can. (Part of the whole pedagogy thing is that during the subsequent experiments you find there are lots of things you missed even though looking right at them – like whatnot, who has not seen that the blue portion of the flame extends well up inside but it gets hottest I think in the final part of the combustion – and brightest – where the carbon is burning, which is very much like burning coal, which is used to melt steel).

          The variations in color are noted and questions come up like why doesn’t the wick burn up and why does it have a red dot on the end that is consumed at the exact same rate that the wax is used up. A candle is a very sophisticated device. So, the pyrex tube – to avoid breaking glass from the heat differences – is held with a clothespin and put into various parts of the flame to sample the gases. Eventually one finds that if you put it int he right zone in the center that the gases coming out the end can be lit and will stay lit and burn just like the candle flame. You could do more with whatever is happening when it won’t burn but that is too much for the first week.

          The paper cards or 3×5 cards are very clever instruments. You quickly insert them horizontally into the flame. Hold them still until you see some scorching then snatch it out. The class needs some demonstrations and practice to avoid waving about and dropping flaming 3×5 cards. If they catch fire there is a dish of water they can lay them in.

          If you do this at several heights of the flame you get a scorched ring temperature profile that shows the center is nearly cold. The bottom is hot and the outer edge is hotter and the top will burn very quickly.

          There are more experiments like causing water to rise in a closed up vessel, etc. Blowing breath though a solution that precipitates if there is CO2 and doing the same with the candle, etc. I have done this with some adult classes where they took it seriously and they had a great time. They are nearly universally surprised they can learn so much about something so common. And seeming so common when they start, it is a really good lab to train in writing up a worthwhile lab notebook entry.

          Another simple demo that can get people interested is this: Have everyone cover their eyes. Light a sheet of writing paper on fire. Blow it out but still smoldering a bit and quickly move among the people or rows or whatever. Drop it in the sink and ask them to open their eyes and tell you what they smell. The vast majority will tell you burnt marshmallows or burnt cookies that baked too long. You then launch into some Q&A and get into cellulose being basically made of sugars and that is why some animals can eat it. And that leads to carbohydrate and hydrocarbon and how us carb eaters burn carbs with oxygen and exhale CO2 and water while keeping our bodies at a toasty 100F for 80 years or more. And combustion engines use hydrocarbons (just reverse the words? That is strange.) and exhaust CO2 and water. We burn sugars. Cars burn straight carbon-hydrogen chains (or the “greenest” methane with 1 carbon and 4 hydrogen).

          The difficulty in chemistry is that it gets complicated. First with all the orbitals and bonds and electrons and electronegativity and ionic and covalent then with moles and stoichiometry. Too many students today are too math challenged to get through it without feeling overwhelmed. Plus we teach the sciences backwards as if biology is the easiest. We teach biology then chem then physics as if physics is the hardest. In bio the kids will say something like oh, today we finally hatched our chicken from an egg. The truth is it should be more like WTF? We built a f*cking chicken? By far the most complicated stuff in the universe – as far as we know.

          Well. I got carried away there :-)

  4. Most enjoyable! I was expecting stilted language but it only seemed a bit formal.

    Loved the “dropping flame” demo in one of the earliest chapters. I had never seen that before.

  5. Faraday is one of my scientific heroes. There is an excellent biography of him:
    He preceded Maxwell in showing that light was electromagnetic, and if you look up the Faraday paradox you will find that he also asked a damn good question which was only properly answered by Einstein:

    1. Well, actually, maxwell essentially formulated faraday’ observations into mathematics, a skill the former had no chance to develop.

      Make no mistake, Maxwells’ laws are Faradays work but he realised the mathematical relationships behind them

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