 What evidence do we have for the value of Avogadro's number? 6.02 times 10 to the 23rd. Here we're going to demonstrate one way to find Avogadro's number experimentally. And while we're at it, we're also going to look at water and realize that water is composed of two parts hydrogen to one part oxygen. In order to calculate Avogadro's number, we're going to use an electrolysis device. And this electrolysis is taking energy and converting the water to hydrogen and oxygen. And we need two pieces of information in order to do our calculations. We need the current that's flowing and the time of that current flow to create 10 milliliters of hydrogen gas. While we're at it, we're also going to look at the mole ratio of hydrogen to oxygen. And we will be able to see by the gas produced, two milliliters of hydrogen will be produced for every one milliliter of oxygen. On the screen, you can see the calculations for Avogadro's number experimentally. You can see that our experimental value is very near the 6.02 times 10 to the 23rd as stated in our text. So you can see that this is one method of using an experiment to determine the actual value for Avogadro's number. You also saw that the volume of hydrogen to oxygen was a 2 to 1 ratio. And therefore we know it's H2O.