Have you ever noticed you can drink two or three 4% beers and barely feel it? But if you drink two or three 5% beers, you're wasted?

Obviously it's because there's more alcohol. But why does that extra 1% seem to get you SO much drunker? Here comes the science.

(Photo illustration by Chris Furlong/Getty Images)

It's because the average person can only process one unit of alcohol per hour. A "unit" is 10 milliliters, and a 4% beer has 1.4 units.

If you drink one 4% beer and your body can only process one unit, that means there are still 0.4 units of alcohol left over in your system after one hour, because 1.4 units minus 1 unit equals 0.4. Got it?

Then say you have another beer the next hour. Your body can still only process 1 unit. So after the second hour, you end up with 0.8 units of alcohol in your system.

Now, a 5% beer has 1.8 units of alcohol, exactly 0.4 more than a 4% beer. That doesn't sound like that much. But if you do the math again, you end up accumulating 0.8 units of alcohol per hour. And after two hours, it's up to 1.6.

So even though 5% beer only has 25% more alcohol than 4% does, you end up with twice as much booze in your system. If you drink beer with an even higher alcohol content, it goes up exponentially.