 Hello everyone! Today I'm going to show you how to make a 500ml of a 70% ethanol solution. What do we need for this? A 100% ethanol, distilled water, a measuring cylinder to measure our volumes, a funnel to avoid spillage, a bottle labeled 70% ethanol for my funnel solution, some gloves and of course my lab coat. And now I'm going to work out how much of each solution I need to make this. So stage one, the ratio ethanol to water. If it's 70% ethanol, that means that there is 30% water as 30 and 70% was 100%. So the ratio is 70 to 30%. In other words, 7 parts of alcohol to 3 parts of water because 7% to 3 equals 10%. But we want 500ml in total. So stage two, 500ml total. So by applying the ratio to 500, we obtain 7 over 10 by 500 is alcohol equals 350ml. And 3 over 10 by 500 is water and equals 150ml. So we now have 350ml of alcohol plus our 150ml of water which equals 500ml. So let's go ahead and make it up now. Because we're handling alcohol, I need to put my gloves on. One last recommendation, because the scale of these cylinders is fairly imprecise at the very bottom, we need to pour in the larger volumes first. In this case, it's our alcohol. I put my eye at the level of the 350ml. I pour the alcohol until the bottom of the miniscule touches the line. So now I'm going to complete up to the 500ml with water. Okay, it's nice. So now I'm going to put the funnel in my 70% bottle of alcohol and pour my liquid in. And that's it. We just made our 500ml of 70% alcohol.