If you’re a fan of Colorado’s professional sports teams, you often hear about the “altitude advantage” that exists due to Denver’s mile-high elevation. With regard to the Colorado Rockies, does a baseball really travel that much farther, or faster, just due to elevation? How much of an advantage does altitude provide? If a baseball stadium, like Coors Field, was built at even higher elevation could it make for an even greater advantage?
The forces that act upon a baseball when it’s hit include gravitational force and air resistance force. Since gravity is relatively a constant no matter the elevation, let’s explore air resistance force. Now there are several factors that can affect air density such as temperature, air pressure, altitude, and humidity. Compared to most ballparks in the MLB, Coors Field in Denver is at a much higher elevation and the humidity levels in Denver are generally much lower. So naturally it is safe to assume that the air is thinner and would have less resistance towards a baseball — but of course humidity will play an opposing factor, so how can we measure this?
In baseball the Neeley Scale is used to take air pressure into account. This scale finds the air density index based upon elevation, pressure, temperature, and humidity. The Neeley Scale ranges from 0-100, and makes understanding air pressure a bit easier. A 0 on the scale would occur at very high elevation, on a very hot day. A 100 on the scale would occur at sea level on a very cold day. It is often assumed that high humidity would mean more air pressure, but actually the opposite is true. So that means a baseball traveling through humid air will actually travel farther than a baseball hit in air with low humidity. It seems counter intuitive, but it’s actually because there is more hydrogen in humid air, which is lighter and easier for a projectile to fly through. Low humidity air contains more nitrogen which is heavier, and slows the projectile.
So back to the original question, does a baseball really travel farther at high altitude? Based on the Neeley Scale the average summer air density in Denver (elevation 5,280ft) vs San Diego (elevation 62ft) is as follows:
So according to the Neeley Scale, Denver has much thinner air, and you would assume a baseball would travel much further. Air Density is usually measured in kg/m^3. If you convert the same data into those units, Denver has an average air density of .966kg/m^3 and San Diego has 1.182kg/m^3. As you can see on the chart below this difference in air density means that two identically hit baseballs would result in the Coors Field baseball traveling 10 meters (or 32.8ft) farther!
So yes, a baseball will go farther at high altitude, and the higher in elevation you climb, the farther the ball could potentially travel. If the Rockies want an even greater home field advantage, should they move their home stadium to Leadville CO at 10,151ft? There are certainly pros and cons to each answers, let us know what you think!
To read more, check out this great article by Rhett Allain about air density’s effects on the Home Run Derby
Author: Leo Borasio