Sunday Science Moment- July 3rd 2016

SUNDAY SCIENCE MOMENT

July 3rd 2016

Ever wonder why a hot air balloon floats? The air in the balloon has the same properties and chemical make up as the air around the balloon, so why does it begin to rise when filled up? It all has to do with the air temperature. When you heat up a balloon, the warmer air expends to fill up the balloon. The air inside the balloon becomes less dense then the air around it and allows the hot air to rise. This concept helps explain practical applications like this one, though on the Fourth of July there is a different reason to talk about air masses. An understanding of warm and cold air masses comes into play when figuring out why we can hear our neighbor’s fireworks down the street. 

When the firework goes off, BOOM, that sound wave travels out in every direction until it is dissipates by running into object around the blast. Commonly known as attenuation, the sound wave can only travels as far as objects will allow it to or until it runs out of energy. One of those objects that sound waves can run into is air itself. You see every sound wave needs a medium for which it can travel through, such as water, air, or a solid object. If you watched a movie where there is an explosion in space with a loud boom, they are wrong. Space has no medium so sound cannot travel from point a to point b. So when it comes to air masses, it all depends on what kind of medium is in place that determines how far that sound wave travels.

What I have created is a firework going off over downtown Youngstown. To the left is a cold air mass and to the right is a warm air mass. The current conditions for the Fourth of July right when the fireworks go off are going to be wet and warm. Since the air is warmer it means that the molecules are moving faster when compared to a cold air mass. Due to the fact that there is a warm air mass in place means that, like the hot air balloon, the air is less dense. This allows the soundwave to move faster, covering more distance in less time. With this information we can figure out that since the sound wave is moving further in less time it means that there is less time for the sound wave to attenuate or dissipate. 

In the picture above we can see that in the same amount of time the soundwave in the green warm air mass is traveling faster than the sound wave in the blue cold air mass. After a period of a few second the sound wave moving through the warm moist air mass will move further before dissipating. As seen below the other sound wave did not travel as far and has already dissipated. So what does this mean for people throughout the Valley on this Fourth of July?

It means one of several things; first it means that the sound wave will travel further so those people down the street launching fireworks might sound like they are actually in your front yard. You will also most likely to hear the fireworks from the street over and probably even a few neighborhoods over. Also if you have any pets, they are more likely to hear fireworks even further away than a few neighborhoods over. So if they are scared of fireworks, like my dog, they might be sleeping as close as they can to you tonight. Also for those trying to go to bed early, you will most likely be kept up from the loud bangs until your neighbors go inside. Lastly, if you plan on launching any fireworks that are not allowed in Ohio, just remember that tonight; your angry neighbors will be able to hear you loud and clear. Just a friendly heads up.

If you have any weather related questions or want something explained, let me know. Enjoy the weather and I'll be back next week for the next Science Moment.