Eels are like snakes of the ocean: they’re skinny, wiggly and have no legs. But while snakes are reptiles, eels are fish. Most exciting of all is the electric eel — which isn’t an eel at all, but a type of knifefish. Electric eels use electricity to drive away animals who might try to eat them. An electric eel can pack a 600-volt shock! The good news is, when electric eels are just swimming around, they send out a much nicer 10-volt signal. That sounds like that could power our toys…as we’ll see from the math below!
Wee ones: If you have 3 pet electric eels and 6 non-electric eels, which animal do you have more of?
Little kids: How many legs would you, your pet dog and your pet electric eel have together? Bonus: If you have 4 pet electric eels and each one can light up 2 light bulbs, how many bulbs can they light up together?
Big kids: If every electric eel makes 4 volts of electricity, can 8 electric eels run your 44-volt ice cream maker? Bonus: How many 4-volt electric eels in total would you actually need?
The sky’s the limit: If an eel can really shock you with 600 volts, how many 1 1/2-volt AA batteries do you need to match that? (Hint if needed: How many 3-volt batteries would you need?)
Wee ones: More regular eels, because 6 is more than 3.
Little kids: 6 legs, since the dog has 4 and the electric eel has none. Bonus: 8 light bulbs.
Big kids: No, because together they make only 32 volts. Bonus: 11 electric eels.
The sky’s the limit: 400 batteries! To help solve this, if the batteries were twice as strong at 3 volts, you’d need just 200 of them. So at half the strength (1.5) you need twice as many batteries.
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.