So absorbance right here.

So let me do that in a different color.

So let's say there's some unknown concentration, and you figure out its absorbance is right over here.

So let me write down M for molar.

Here is another example of something which is this is a little spectrophotometer.

And you measure its absorbance, and you just get some number here.

let's say 0.2 molar.

So you measure its absorbance and you get its absorbance.

What I want to do in this video is to talk a little bit about spectrophotometry.

And over here you're measuring absorbance, in the vertical axis you measure absorbance.

The Beer Lambert law tells us that the absorbance is proportional

You could then measure for some unknown concentration.

Now, if I were to integrate both sides, I get uv this should be review is equal to the integral of u prime v, with respect to dt but I'm just doing a little bit of shorthand now plus the integral of uv prime.

The integral of u prime times v.

UV vectors

UV mapping

If transmittance is a low number, that means you're absorbing a lot.

A higher number says your transmitting a lot.

So the integration by parts just tells us that the integral of uv prime is equal to uv minus the integral of

The integral of u well, let's say uv prime, because that will match what we have up here better is equal to both functions without the derivitives, uv minus the integral of the opposite.

So we have this integral of u prime v is going to be equal to this, uv minus the integral of uv prime.

So it's proportional to the path length times the concentration.

Light Speed

Black cloth absorbs light.

Black paper absorbs light.

It goes, I don't know, 0.1, 0.2, 0.3, so on and so forth.

So let's apply this.

So let's apply the integration by parts.

This is actually a picture of the spectrum of the Sun.

So if transmittance is a large number, absorbance is a small number, which makes sense.

I'm sitting on a train.

AAVSO Light Curves...

There are these flashes

We use far red light, but even that's a problem because it gets absorbed so quickly.

If you're good at absorbing, that means you're not transmitting much.

The x ray absorption spectroscopist's periodic table

It cannot hide behind the black hole.

So that's minus 1 over s e to the minus st, times v, sine of at, minus the integral.

But the boundary stays.

luminosity, top right.

If you're good at transmitting, that means you're bad at absorbing, you don't have a lot to absorb.

Integration by parts. uv.

What's going on here?

Or another way to say it is that the absorbance is equal to some constant it's usually a lowercase epsilon like that and this is dependent on the solution, or the solute in question, what we actually have in here, and the temperature, and the pressure, and all of that.

The most fundamental is called the breathing loop.