A storm is approaching, and suddenly there is thunder, it seems very close, even scary! But how "close" is lightning really? Calculating the distance to the lightning bolt can make you feel at ease if you are in a safe place or, conversely, it can convince you to find it as soon as possible. So how close was that lightning bolt? Read the article to find out.
Steps
Method 1 of 1: Calculate the Distance to the Lightning Bolt
Step 1. Look to the sky for lightning
Step 2. Count the seconds that pass before you hear the thunder
If you have a digital clock or similar, start counting as soon as you see the lightning, and stop as soon as the thunder starts. If you don't have a watch, count as accurately as possible. Count out loud saying One Thousand and One, One Thousand and Two….
Step 3. Calculate the distance to the flash in miles or kilometers
Sound travels through the air at the speed of one mile every five seconds and one kilometer every three seconds. For this reason, if you want to find out how far you are from the lightning bolt, divide the number of seconds elapsed by 5 if you want a result in miles, and by 3 if you want it in kilometers. This difference in perception between lightning and thunder is due to the fact that light travels much faster than sound. Here's what you need to do:
- Let's assume 18 seconds have elapsed. To find out your distance to lightning in miles, divide 18 by 5 and you get 3.6 miles. To find out your distance to the lightning bolt in kilometers, divide 18 by 3 and you get 6 kilometers.
- Although you will not be able to get a completely accurate result due to the possible change in temperature and humidity, elements that slightly alter the speed of sound, this method is accurate enough to calculate your distance to lightning.
Step 4. Calculate the distance to the lightning in feet or meters
Sound travels at a speed of approximately 344 meters or 1,129 feet per second. To calculate your distance to the lightning bolt in meters, round the figure 344 to 340 and multiply the number of seconds elapsed by 340. To calculate your distance to the lightning bolt in feet, round the figure from 1,129 to 1,130 and multiply the number of seconds elapsed for 1,130. Here's what you need to do:
Let's assume 3 seconds have elapsed. Multiply that number by 340 to get your distance in meters. 3 x 340 = 1,020 meters. Multiply that number by 1,130 to get your standing distance. 3 x 1,130 = 3,390 feet
Advice
- If you are near frightened children, calculate how far the lightning bolt is and tell them, the fright will pass and they will want to know how you did it.
- Spread this method among the people you know. It is still widely believed that the number of seconds that elapse equals the number of miles away from the lightning.
- It is a method that can also be used with students, to teach how to calculate distance and time.
- The sound is transmitted through the air at slightly different speeds depending on the temperature and humidity, but this difference is so small that it is practically irrelevant in the calculation.
- If you have a compass and a map, try to indicate with a line the direction in which you see each lightning, and mark the distance calculated based on the thunder with a cross.
- In this method there are obvious limitations, to improve the distance estimation repeat the evaluation for more lightning strikes in a row.
- If a lightning bolt falls 1 mile away, you will see it after about 0.00000536 seconds, but you will only feel it after about 4.72. By calculating the difference between these two phenomena, a person feels lightning after about 4.71999 seconds of its actual manifestation.. For this reason, an approximation of 5 seconds per mile is sufficiently adequate.
Warnings
- Lightning can be deadly. Search wikiHow and find out how to be safe during a thunderstorm.
- Given the way sound spreads through the air and can be reflected by various elements such as mountains or buildings, this is not a 100% safe and reliable method of calculating the distance of a lightning strike. Do not entrust your life to this method, consult the meteorological service.
- Be careful practicing this method outside: if you are close enough to hear the thunder, you are also close enough to be struck by lightning. It is possible to be struck by lightning even more than 10 kilometers away from a storm, so if possible find shelter and make yourself safe.
- If you don't see lightning, the thunder you hear may have bounced off a building or mountain, this effect will further delay the perception of the sound effect (lightning and thunder will make the lightning appear farther than it actually is). Consider the effect of your surroundings (especially large ones), objects and obstacles because the sound flexes and bounces. Any indirect path is certainly wider than the actual distance you are trying to calculate.
- If the lightning strikes nearby, seek shelter so as not to run the risk of being electrocuted yourself.
