That doesn't sound like a lot but that's actually, You're yelling with an intensity of, say 10 to the negative fifth. Scale because it takes enormous intensitiesĪnd small intensities, turns them into nice intensities. That's why we like this formula which is our Decibel Logarithm took this enormous number of billion and turned it into nine. Nine, and that's why logarithms are good. So the answer to this questionįor the logarithm is nine. Ninth because I got one, two, three, four, five, six, That's hard to deal with but log takes 10 and asks what number can I raise 10 to in Log took a huge number, 100000,Īnd turned it into five. I raised 10 to get 100000, then that's the answer to this that log base 10 of 100000 is five. If I raise 10 to theįifth, I'll get 100000. This entire number hereĪnd asks what number should I raise 10 to Number would I raise 10 to in order to get this number in here. Okay, if I'm log base 10, log wants to know what Log base 10 of a numberĮquals, here's what it does. Logarithm, if you don't remember, here's what a logarithm does. Or really small numbers and turn them into nice numbers. We don't want to measure from one to a trillion or a trillion to one. We want to scale that's small or maybe like one toġ00 to measure loudness.

This one watt per square meter is a trillion times bigger than this side. But once you get to about one watt per square meter, this

Six, seven, eight, nine, 10, 11, with a one watts per square meter all the way where there's no upper limit. This is your point zero, zero, say three, four, five, This means we can hear from 10 to the negative 12 watts per square meter. Watts per meter squared, there's a huge range of human hearing. Hear such a soft sound, 10 to the negative 12 'Why in God's name did the physicist have 'to put logarithm in here? 'This scare me.' This used to scare me too. Spread one watt over the entire land area of Germany,Ībout three times over, and still it's intense enoughįor the human ear to hear. This one watt be spread over and still be intense enoughįor the human ear to hear it? What do you think? Football field? I don't know, a city? No, it turns out. How diluted could one watt be spread over? How large of an area could If you have one watt, howīig could you make this area? How, spread out. If you have one watt, how big of an area? A watt isn't really that much. Through the square meter, your ear would still be able What this says is thatĮven if only one trillionth of a joule per second passes This is one trillion ofĪ watt per meter square. Than that, a human ear that's healthy shouldīe able to detect it. What that means is this is the softest possible sound you can hear. This 10 to the negativeġ2 watts per square meter represents the threshold of human hearing. This part of the equation is my favorite.

This gives you an idea of how much energy per second pass throughĪ certain amount of area. How many joulels of sound energy per second pass through the one square meter? That would be the number of watts per meter squared which If you asked how many joules per second pass through that one square meter. The power that passes through that area will be, how many joules? If you figure you how many joules pass through this one square meter. This doesn't have to beĪn actual physical object. Power's in, what? Power measure going to watts. You got your ear and a sound wave, say, is coming toward your ear. What this means, think about it this way. In Physics, intensity is defined to be the power divided by the area. If you didn't multiply byġ0, you'd have the bel scale but this is multiplied by 10. The fact that this is the Deci-bel Scale and Somewhere reader just in volume because we're going to The number of decibels and we abbreviate decibel Logarithm, base 10 of I divided by 10 to the negativeġ2 watts per square meter. This is the scale that we use to figure out the loudness of a sound.

I'm going to tell you about the Decibel Scale.

Decibel loudness scale