We went to the aquarium, the kids like it. In the Amazon river section, they have an electric eel. Here is the sign next to the Eel.
Sorry for the poor image quality. I took the picture with my crappy phone and didn’t even realize it was bad until later. I used some magic on it to make parts of it readable, but if that was not good enough, here is what it says:
The Electric Eel is the most powerful of all the electric fishes. It can discharge up to 650 volts: six times the power of a household current. A shock can fend off attackers or stun prey so the eel doesn’t risk getting hurt in a struggle.
A person might survive one blast from an Electric Eel, but not several.
Let me address this in three ways. First, what is wrong with this. Second, why is this a problem that it is wrong. Third, what would I have put on this board.
What is wrong with this?
The biggest problem seems to be the confusion between electric potential (measured in volts), power (measured in watts) and current (measured in amps). The narrative clearly says that the 650 VOLTS is six times the POWER of household CURRENT. Those are three different things.
If you look at the Wikipedia page on electric eels, it says the eel could produce 500 volts at 1 amp of current. For electric circuits, the following is the relationship between electric potential, electric current and power:
This would make the eel capable of 500 watts in the attack.
What about a household circuit? First, these are alternating currents (AC), but let’s just pretend it is DC for simplicity. A normal household outlet is at 120 Volts and can produce currents of about 10 amps. This would be a maximum power of 1,200 watts. So, the eel is not 6 times the power of the household outlet.
Note: I would not recommend sticking your finger in either an electric eel nor in a household outlet.
Why does this bother me?
Really, this is a similar problem to the problem with ESPN Sport Science. Here is a great opportunity to help people learn something, or at the very least do no harm. Also, clearly there was some effort put into this production. I bet the sign alone cost at least $100. Yet it appears that no one bothered to contact a local high school physics teacher to look over this. If you can’t find someone, email me. I will be happy to look over your sign.
I could see if a blogger made this and it was wrong. Mistakes happen, it is no big deal – especially when it is just one person. But this case is different. How long will that sign be there?
Ok Mr. big shot blogger man. What would you put? Well, first I would state the important details.
An electric eel has multiple cells along its body that create a change in potential of over 500 volts. The typical current produced in an electric eel attack is around 1 amp.
Now, the problem is that most people of no experience with with 500 volts is like or 1 amp is like. So, I could add something like this:
500 volts would be the same potential as about 330 D-cell batteries connected together. A typical two-battery flashlight might use a current of about 1 amp. However, since the eel has a much larger potential difference, the effects can be severe.
Just my first thought. You could probably come up with a cool graphic to show a comparison between the eel and a flashlight. Oh – how about two electrodes that visitors can touch and get shocked. Next to it, there could be a sign that says “that hurt, didn’t it?”