Why does it take about 5 seconds before we can hear the thunder of a lightning?
That is because light travels much faster than sound waves. We can estimate the distance of the lightning by counting how many seconds it takes until we hear the thunder. It takes approximately 5 seconds for the sound to travel 1 mile.
The thunder travels away from the lightning bolt and in about 5 seconds it will have traveled 1 mile. So for every 5 seconds you count before you hear thunder, that equals 1 mile. Now the speed that the sound of thunder travels varies depending on the air temperature.
If you count the number of seconds between the flash of lightning and the sound of thunder, and then divide by 5, you'll get the distance in miles to the lightning: 5 seconds = 1 mile, 15 seconds = 3 miles, 0 seconds = very close. Keep in mind that you should be in a safe place while counting.
Thunder and lightning all occur due to the release of energy – thunder is a soundwave, and lightning is the emission of electromagnetic energy. The reason we see a flash of lightning before hearing thunder is because light travels faster than sound.
The primary reason for this is that the sound shock wave alters as it passes through the atmosphere. Sound travels roughly 750 mph (1,200 km/h), or approximately one mile every 5 seconds (one kilometer every 3 seconds).
In nature, a lightning flash and the associated thunder occur at almost the same time in a thunderstorm. A person on the ground sees the lightning flash before hearing the thunder because light at a speed of around 300,000,000 meters per second travels much faster than sound which moves at 340 meters per second.
What is the distance of the flash from the observer if the velocity of sound is 330 m/s? (speed of light 3 x 108m/s) (Ans: 1650 m.
Remember, safety first! The golden rule of lightning safety is if you hear thunder, you should seek shelter inside of a substantial building or an enclosed, metal-topped vehicle. Thus, always plan to photograph lightning from inside a safe shelter or from inside a car.
The Lightning 30/30 Rule
If it takes less than 30 seconds to hear the roaring sound of thunder after seeing the flash of light, the lightning storm is close enough to pose a danger. So, after the storm ends, you should wait for at least 30 minutes before reengaging in outdoor activities.
Storm Distance Safety Tips
The CDC tells us, “when thunder roars, go indoors.” They also advise following the 30-30 rule, which means if less than 30 seconds passes after lightning strikes before hearing thunder, you should take shelter.
What is thunder made of?
Lightning is a discharge of electricity. A single stroke of lightning can heat the air around it to 30,000°C (54,000°F)! This extreme heating causes the air to expand explosively fast. The expansion creates a shock wave that turns into a booming sound wave, known as thunder.
In fact, lightning can heat the air it passes through to 50,000 degrees Fahrenheit (5 times hotter than the surface of the sun).
The cold air has ice crystals. The warm air has water droplets. During the storm, the droplets and crystals bump together and move apart in the air. This rubbing makes static electrical charges in the clouds.
So sound travels 1 kilometer in roughly 3 seconds and 1 mile in roughly 5 seconds. When you see the flash of a lightning bolt, you can start counting seconds and then divide to see how far away the lightning struck.
Every 5 seconds between when you see lightning and when you hear the thunder is one mile. If you count 10 seconds between the lightning and thunder, the lightning struck 2 miles away. For further information about lightning and safety, visit the website of the National Lightning Safety Institute.
Thunder starts as a shockwave from the explosively expanding lightning channel when a large current causes rapid heating. However, it is possible that you might see lightning and not hear the thunder because it was too far away. Sometimes this is called “heat lightning” because it occurs most often in the summer.
Lightning can jump through windows, so keep your distance from them during storms! The second way lightning can enter a building is through pipes or wires. If the lightning strikes utility infrastructure, it can travel through those pipes or wires and enter your home that way.
1. The speed of lightning. While the flashes we see as a result of a lightning strike travel at the speed of light (670,000,000 mph) an actual lightning strike travels at a comparatively gentle 270,000 mph.
When lightning strikes, the narrow channel of air through which it travels reaches temperatures of up to 30,000 °C almost instantly. This intense heating causes the air to rapidly expand outward into the cooler air surrounding it creating a rippling shockwave which we hear as a rumbling thunder clap.
Sound travels roughly 750 mph (1,200 km/h), or approximately one mile every 5 seconds (one kilometer every 3 seconds). The speed actually varies greatly with the temperature, but the thumb rule of 5 seconds per mile (3 seconds per kilometer) is a good approximation.
How far away did lightning strike when the rumbling of thunder was heard 6 seconds after the lightning flash?
For example if you see a flash of lightning and you count for 6 seconds before you hear thunder, then the lightning occurred 2 km away.
Keep in mind that thunder is a compression, or shock wave... caused when lightning heats the air. A 'clap' comes from a single, straight lightning segment-often overhead.
When You See Lightning, Count The Time Until You Hear Thunder. If That Is 30 Seconds Or Less, The Thunderstorm Is Close Enough To Be Dangerous – Seek Shelter (if you can't see the lightning, just hearing the thunder is a good back-up rule). Wait 30 Minutes Or More After The Lightning Flash Before Leaving Shelter.
“Bolts from the blue” can strike 10-15 miles from the thunderstorm. Myth: Rubber tires on a car protect you from lightning by insulating you from the ground. Fact: Most cars are safe from lightning, but it is the metal roof and metal sides that protect you, NOT the rubber tires.
The safest location during a thunderstorm is inside a large enclosed structure with plumbing and electrical wiring. These include shopping centers, schools, office buildings, and private residences.
We recommend a 30-minute wait after the last flash or thunder. The two together provide the basis for the '30-30 rule'. The first 30 is for the 30-second flash-to-bang time when a safe place should have been reached. The other 30 is for the 30 minutes' wait after the last lightning or thunder.
Lightning can travel 10 to 12 miles from a thunderstorm. This is often farther than the sound of thunder travels. That means that if you can hear thunder you are close enough to a storm to be in danger of being struck by lightning.
Stay inside a safe building or vehicle for at least 30 minutes after you hear the last thunder. While 30 minutes may seem like a long time, it is necessary to be safe. Finally, some victims were struck inside homes or buildings while they were using electrical equipment or corded phones.
Stay away from windows and doors, and stay off porches. Do NOT lie on concrete floors or lean on concrete walls during a thunderstorm. Lightning can travel through any metal wires or bars in concrete walls or flooring. Don't use corded phones.
Fact: NO PLACE outside is safe when thunderstorms are in the area. If you are caught outside in a thunderstorm, keep moving toward a safe shelter.
Why do people count after lightning strikes?
Jackson Browne from the Bureau of Meteorology said counting the seconds between when you see a strike of lightning and hear the accompanying thunder could help you figure out how far away the lightning is.
The rapid expansion of the air produces a sonic boom that you hear as thunder. However, at the molecular scale, chemical changes can alter the atmosphere on a highly local level and leave behind an aroma.
The smell is probably ozone, which typically has a sweet, pungent aroma. In stormy weather, lightning splits atmospheric nitrogen and oxygen molecules. These can then combine into nitric oxide, which, with further reactions, forms ozone.
As the heated air expands, the pressure drops, the air cools, and it contracts. The result is a shock wave, with a loud, booming burst of noise sent in every direction.
Lightning is hot. Really hot. It can reach temperatures as high as 50,000 degrees Fahrenheit, five times hotter than the surface of the sun, and even hotter than lava here on Earth.
The Earth's Core
Right down in the centre of our Earth, at its core, temperatures reach 5,377 degrees Celsius.
Up to 50,000 degrees Fahrenheit, maybe even more.
Lightning doesn't strike the ocean as much as land, but when it does,it spreads out over the water, which acts as a conductor. It can hit boats that are nearby, and electrocute fish that are near the surface. If you're at the beach and hear thunder or see lightning, get out of the water.
A lightning bolt can reach 54,000 degrees Fahrenheit, about five times hotter than the surface of our sun. Lightning strikes the United States 20 million times per year. Lightning moves about 30,000 times faster than a bullet. Thunder is the result of the rapid heating and expansion of air caused by a lightning flash.
A "Bolt from the Blue" is a cloud to ground lightning flash which typically comes out of the back side of the thunderstorm cloud, travels a relatively large distance in clear air away from the storm cloud, and then angles down and strikes the ground.
Why is thunder so loud?
The temperature of the air in the lightning channel may reach as high as 50,000 degrees Fahrenheit, 5 times hotter than the surface of the sun. Immediately after the flash, the air cools and contracts quickly. This rapid expansion and contraction creates the sound wave that we hear as thunder.
Claps are loud sounds lasting 0.2 to 2 seconds and containing higher pitches. Peals are sounds changing in loudness and pitch. Rolls are irregular mixtures of loudness and pitches. Rumbles are less loud, last for longer (up to more than 30 seconds), and of low pitch.
The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. Nearly 1,800 thunderstorms are occurring at any moment around the world. That's 16 million a year! Despite their small size, all thunderstorms are dangerous.
Lightning and thunder happen at the same time. But you see lightning before you hear thunder because light, which travels a million times faster than sound, arrives almost instantly. Sound, on the other hand, takes about five seconds to travel one mile.
There are two main types of lighting: intra-cloud lightning and cloud-to-ground lightning. Intra-cloud lightning is an electrical discharge between oppositely charged areas within the thunderstorm cloud. Cloud-to-ground lightning is a discharge between opposite charges in the cloud and on the ground.
It requires a 30 minute delay, but this may vary because the time count will restart if a lightning strike occurs within the 8 mile radius.
First reported in 1994, dark lightning is estimated to flash around the world about a thousand times each day. But scientists have only a hazy understanding of how it initiates. They generally agree dark lightning is sparked by the electric fields generated by thunderstorms and lightning bolts.
White: most powerful lightning color
White is the most dangerous color of lighting. It suggests both a low concentration of moisture and a high concentration of dust in air. We all are aware that being hit by lightning can have serious consequences.
An observer may see nearby lightning, but the sound from the discharge is refracted over their head by a change in the temperature, and therefore the density, of the air around him. As a result, the lightning discharge seems to be silent.
Because light travels through the air roughly a million times faster than sound does, you can use thunder to estimate the distance to lightning. Just count the number of seconds from the time you see a flash until you hear thunder.
Why the flash of lightning reaches us first and sound of thunder is heard a little later?
The velocity of light which is equal to 3 × 108 m/s is much greater than the velocity of sound which is equal to 344 m/s. Hence, we see the flash of lightning much before the sound of thunder reaches us.
When You See Lightning, Count The Time Until You Hear Thunder. If That Is 30 Seconds Or Less, The Thunderstorm Is Close Enough To Be Dangerous – Seek Shelter (if you can't see the lightning, just hearing the thunder is a good back-up rule). Wait 30 Minutes Or More After The Lightning Flash Before Leaving Shelter.
Thunder starts as a shockwave from the explosively expanding lightning channel when a large current causes rapid heating. However, it is possible that you might see lightning and not hear the thunder because it was too far away. Sometimes this is called “heat lightning” because it occurs most often in the summer.
We see lightning first and then hear thunder because light travels faster than sound.
That's when a lightning bolt directly hits the building you're in. Lightning can jump through windows, so keep your distance from them during storms! The second way lightning can enter a building is through pipes or wires.
The normal intelligible outdoor range of the male human voice in still air is 180 m (590 ft 6.6 in). The silbo, the whistled language of the Spanish-speaking inhabitants of the Canary Island of La Gomera, is intelligible under ideal conditions at 8 km (5 miles).
On a standard day at sea level static conditions, the speed of sound is about 760 mph, or 1100 feet/second.
There is no shortest sound detectable by the human ear. Any impulse with enough energy is audible. The shortest detectable tone, identifiable as a tone, would be on the order of 100 ms. It might be shorter for tones of high pitch.
The speed of light is much quicker than the speed of sound.
Once a charged leader makes a connection with the ground, the return stroke occurs. The return stroke is simply the rapid discharge of electricity that has accumulated on the leader. We see this discharge as the bright flash of lightning.
What is the difference between speed of light and speed of sound?
The speed of light is much faster than the speed of sound in air. If you want to compare, the speed of sound in air is ~ 343 m/s and the speed of light is 3x1010 m/s. In other words, light travels 186 thousand miles in 1 second, while sound takes almost 5 seconds to travel 1 mile.
The main risk with landing during a storm, just like with taking off, is microbursts. A microburst is a small but strong column of air in a storm which can affect a plane's direction, making it hard for pilots to keep the plane under control.
Remember the phrase, “When thunder roars, go indoors.” Find a safe, enclosed shelter when you hear thunder. Safe shelters include homes, offices, shopping centers, and hard-top vehicles with the windows rolled up. Seek shelter immediately, even if caught out in the open.
