> "Rozenblit and Keil (2002) have demonstrated that people tend to be overconfident in how well they understand how everyday objects, such as toilets [...]"
I'd be really interested to see what misconceptions people had about flush toilets, but Rozenblit and Keil's paper doesn't seem to really expand on this. (Assuming I found the right paper: http://www.yale.edu/cogdevlab/aarticles/IOED%20proofs.pdf%20... ?)
I've personally assembled and installed a toilet so I am confident that I have an accurate view of how toilets work, but that experience wasn't exactly illuminating; I already knew how they worked. Toilets are pretty simple, anyone who has ever opened the tank of one and looked at it for a minute or two probably has it figured out.
Edit: When other questions from that study include things like " How the liver removes toxins from blood", I don't doubt that they found an overall trend, but it bothers me that a paper like that could include mention of asking questions about toilets, not actually say what people got wrong about toilets, and then because of that paper it is taken as truth that people don't know how toilets work.
I think that most people who look inside the tank and spend a few seconds analysing what happens when you flush have a pretty good idea how that part works. But it's the other end that's more opaque (literally.) What makes the bottom half of the toilet work, where the real magic happens? I think that's the part that most people would struggle with since few of us have transparent toilets and the internal structure isn't always obvious from the external shape of the stool.
This explains how the siphon works to keep the bowl at the same level and to create the force of a "flush". Until I saw a toilet that had the siphon shape visibly exposed on the outside, I don't think I ever thought question how it worked. Once I saw the shape, I immediately thought about it working like a siphon I'd used to pull gas out of my car. For people who have never seen a toilet with the siphon shape exposed, they'd probably have to have siphon experience in some other area to make the leap, or I think how the bowl stays full and flushes would just naturally stay a mystery. Believing that it all happens in the tank might also be enough of an explanation for most to stop thinking about it.
As someone who just suffered through a clog recently, I liked this explanation from an MIT student better. It starts out the same, with a good diagram and a description of the basic principle, but then goes the extra mile with actual physic equations.
I've talked to folks who insist that flush pressure is directly correlated to water pressure. For some toilets this is true, but generally toilets have a reservoir which is used to flush the toilet (you can actually flush the toilet completely disconnected from the water source if you fill the tank).
EDIT: US households. I don't know about toilet arrangements in other countries.
Are you sure you understand how a toilet works? The tank on top is not the toilet. It's a tank that pours water into the toilet. I've looked in the tank and understand how that works.
The toilet is the thing you sit on that holds water. It works by siphon action (something I didn't know until reading links in this thread).
The lack of understanding isn't necessarily a "misconception" -- it may just be incomplete knowledge of the entirety of the system.
I think the question "How does a toilet work?" is much like the question "What happens when you type 'google.com' into your browser and press enter?"[1] I'm sure I have a sufficient understanding of the general idea (e.g. flapper and siphon, or parsing and DNS lookup), but I'm well aware I couldn't reproduce or accurately describe the whole system/process on my own.
The trap and the vent stack that prevent sewer gas from pushing back into the bathroom are not obvious. I'll bet a lot of people don't quite know what the vent is there for.
Maybe so. The paper mentions that they then used the CD-ROM The Way Things Work 2.0 to give their test subjects a more accurate view of how these things work. I actually gave one of my nephews a book from that series (The New Way Things Work) a few years ago, though it mostly covered the mechanics of things.
If the confusion was over things like "how does the siphon work" or maybe "why does the water swirl when it flushes", I think that'd be more understandable.
I'd be really interested to see what misconceptions people had about flush toilets, but Rozenblit and Keil's paper doesn't seem to really expand on this. (Assuming I found the right paper: http://www.yale.edu/cogdevlab/aarticles/IOED%20proofs.pdf%20... ?)
I've personally assembled and installed a toilet so I am confident that I have an accurate view of how toilets work, but that experience wasn't exactly illuminating; I already knew how they worked. Toilets are pretty simple, anyone who has ever opened the tank of one and looked at it for a minute or two probably has it figured out.
Edit: When other questions from that study include things like " How the liver removes toxins from blood", I don't doubt that they found an overall trend, but it bothers me that a paper like that could include mention of asking questions about toilets, not actually say what people got wrong about toilets, and then because of that paper it is taken as truth that people don't know how toilets work.