Perfect weather for the Home Run? Maybe not!

I know what you think of the opening of the Astros division tomorrow: how could they NOT open the roof? The incredible weather we had this week with clear calm skies and lower humidity would seem ideal for a baseball game.

In fact, it is quite ideal for fans. After all, with the low humidity, we all feel lighter and better – the fresh air makes us feel fresh. But low humidity isn’t the perfect environment to hit a home run! Why? This dry air causes more on baseball than humid air.

It’s certainly counterintuitive – after all, humid air seems to drag us along! Our hair is dragging, our run in the park is dragging, the dog is dragging. We all seem to slow down a bit, so wouldn’t humid air slow baseball down? After all, doesn’t baseball have to go through that damp air to reach the fence for a home run?

Basic science is really quite easy to understand. Air has weight. If we call it “molecular mass,” everyone has eleventh-grade chemistry flashbacks and panics. So let’s go with the weight. Our air is largely composed of nitrogen (N) and oxygen (O) with some hydrogen (H), argon and other gases.

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Without getting into the weeds of grams per mole, suffice to say that oxygen has a weight of 16 and nitrogen has a weight of 14 and in our air they are “diatomic” or come in pairs: O2 and N2 which means that O2 weighs 32 while N2 weighs 28. Why is this important? It is the weight of dry air. To dry. It’s heavy.

You know the formula of water: H20 – Two hydrogens and one oxygen. Two hydrogens weigh only 2 and with a single oxygen weighs 16, so the weight of the water molecule is only 2 + 16 = 18. This 18 is much less than the weight of O2′s 32 or N2′s 28. Moist air weighs less than dry air.

What does this have to do with a baseball? Fairly simple – the ball travels through air and if the air is dry, it should travel in heavier air. Baseballs go further in moist, lighter air!

Take a look at this graphic from showing a Homer being hit at a 45 degree angle. They considered a temperature of 70 ° and a standard pressure at sea level (which would correspond to Houston). A 161 mph bullet goes FURTHER in hot, humid weather:

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Since the Minute Maid Park field fence is exactly 409 feet from home plate, a baseball homerun might not get there in a cold, dry atmosphere! Hot and humid means more circuits !! So the question becomes, roof open tomorrow? The temperatures of 3pm will be 87 ° with a dew point of 61 ° which corresponds to a hot and dry atmosphere. So I think I’ll just leave the air conditioning on, shut the roof and hope Altuve finds the right place!

Go Astros!


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