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Distance to Thunder Equation:
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The thunder distance calculation estimates how far away a lightning strike occurred based on the time delay between seeing the lightning flash and hearing the thunder. Since light travels much faster than sound, the delay is primarily due to the speed of sound.
The calculator uses the distance equation:
Where:
Explanation: The equation calculates distance by multiplying the speed of sound by the time delay, then dividing by 3 to convert from meters to kilometers (approximately).
Details: Estimating thunder distance is important for safety during thunderstorms. It helps determine how close lightning strikes are occurring and whether you need to seek immediate shelter.
Tips: Enter the speed of sound (typically 343 m/s at 20°C) and the time delay in seconds between seeing the lightning and hearing the thunder. All values must be positive numbers.
Q1: Why divide by 3 instead of 1000?
A: The division by 3 is an approximation that accounts for the speed of sound being about 343 m/s, and 343/1000 ≈ 1/3, making mental calculations easier.
Q2: What is the typical speed of sound?
A: At 20°C (68°F), the speed of sound is approximately 343 meters per second. This varies with temperature and humidity.
Q3: How accurate is this calculation?
A: It provides a good estimate for most practical purposes. For greater accuracy, use the exact formula: distance = speed_of_sound × time / 1000.
Q4: Why is light considered instantaneous?
A: Light travels at about 300,000 km/s, so the time for light to travel a few kilometers is negligible compared to sound travel time.
Q5: When should I seek shelter from lightning?
A: The "30-30 rule" suggests seeking shelter if the time between flash and thunder is 30 seconds or less (about 10 km or closer), and waiting 30 minutes after the last thunder before resuming activities.