# Weighing an elephant [closed]

Here's another classic I couldn't find on the site:

How can you determine the weight of an elephant without using a scale?

• @MarkN You want to post that as an answer? I was wondering what kind of crazy solutions the people would come up with. Jul 3, 2015 at 14:27
• @MarkN and how much is this standard elephant?
– user88
Jul 3, 2015 at 14:30
• Simply ask the elephant. (and assume a spherical elephant) Jul 3, 2015 at 14:43
• @MarkN What if he didn't know? Jul 3, 2015 at 14:45
• @MarkN that won't work - consider the elephant is male, then he won't know his weight. Now if it's a female, she'll lies about it.
– Alex
Jul 3, 2015 at 14:56

Here's the canonical answer, via the Archimedes Principle:

Put the elephant onto a large boat, and mark the water level that the boat sinks to. Then, take the elephant out and put a bunch of marked weights onto the boat until it reaches the same water level. Add up the masses of the weights to get the weight of the elephant.

Place an object of known mass a fixed distance away from the elephant, and measure the gravitational attraction the elephant exerts on the object. This will let you compute the elephant's mass, and therefore its weight.

• How do you measure gravitational attraction without a spring scale?
– user88
Jul 10, 2015 at 12:28
• I was picturing something like the fixed mass is hanging from the ceiling on a string, and you measure how much it deviates from vertical. Jul 10, 2015 at 13:06
• Oh. That might actually make sense.
– user88
Jul 10, 2015 at 13:18
• the original used wires that twisted, and two sets of giant balls.
– Cato
Feb 6, 2018 at 16:28

Put the elephant on one end of a seasaw with a known weight at the other and keep adding or removing weight until it is in balance?

Alternatively, submerge the elephant in water in a pool that is of known volume and measure the increase in water level.

• You're basically using the seesaw the same way you'd use a two-pan balance, though, which is also a scale.
– user88
Jul 3, 2015 at 14:35
• The water submersion one works, though.
– user88
Jul 3, 2015 at 14:38
• volume != weight Jul 3, 2015 at 14:58
• Yes, however 1 cubic centimeter of water weights 1 gram so conversion is possible, Jul 3, 2015 at 15:02
• How? You will get the weight for the volume of water that is occupied by the elephant. not the weight of the elephant. If an elephant was made of water, this would indeed work as all you would need to know to weight the elephant is his volume, that however is not the case... I might be missing something but this seems wrong and you aren't the only one who gave this answer. Note that this is very different than the Archimedes Principle stated by Joe Z. Jul 3, 2015 at 15:22

You could just do what the Imperial system did and make it a new unit of measurement.
i.e - I would like to purchase 0.002 elephants of chocolate please!

For every new elephant king that appears, we simply change the unit to suit it properly.

Alternative answer: Take the elephant into space, and calculate its gravitational pull on a know mass object (using the universal gravitation equation.)

Take a truck who can support a known weight.

-If the truck can support it, take another truck who can support a little less weight.

-If he can't, take one who can support a little more.

Reproduce until you find the perfect truck and you get his supported weight.

• That's a lot of trucks you're going to break. Jul 3, 2015 at 14:36
• Hmm... that's clever, but usually you can only get a measurement to within 100 or 500 pounds that way.
– user88
Jul 3, 2015 at 14:37
• Also, keep in mind that the elephant is not going to be very happy if you keep putting him on trucks that break underneath him. Jul 3, 2015 at 14:46
• Nobody said that the elephant need to be alive... Jul 3, 2015 at 14:50
• Must trucks rated at 7.5 tonnes are physically capable of carrying more weight than their taxation or licencing class. Jul 3, 2015 at 14:50

My sister came up with this one:

1. Make a small cut on the elephant.
2. Pump out all of its blood.
3. Cut the elephant into pieces and weigh each piece (by putting it in a tank of water)
4. Weigh the bloody stuff. (by putting it in a bag with negligible weight and then putting it in a tank of water)
5. Add up all the weights.
• Your sister is a bloodthirsty little thing :-o Jul 3, 2015 at 16:22
• @randal'thor Well, at first, she was just going to go ahead and cut it up, but she was afraid that if she didn't pump out the blood first, she would miss the weight of the bloddy stuff. Jul 3, 2015 at 16:24
• She couldn't just imagine a really big tank of water? "No, that's ridiculous. Let's go Dexter on this pachyderm." Jul 6, 2015 at 10:50
• @EngineerToast She said she didn't want to drown the elephant. She didn't want to see the elephant suffer at the bottom of a tank and figured that her method would kill the elephant faster. And besides, she was going to cook the chunks of elephant meat when she was done. Jul 6, 2015 at 14:31
• If you're going to do that, why not just open the fridge door, put the elephant in, and close it?
– user88
Jul 10, 2015 at 12:30

Elephants are known for their patience so find yourself a beach chair, some tanning lotion, LOTS of beer and a good pair of sunglasses. (Snacks are a plus but avoid peanuts as they may render the whole thing useless)

Once you are set , start the timer on your watch and observe the elephant. Once the elephant is tired of you staring at it and leaves, stop your timer. And you will know how much that elephants waits.

Get it ? get it?