Wonderful Engineering

Physicist Calculates The Energy Of The Beirut Blast By Measuring The Displacement Of Bride’s Dress

Physicist calculates the energy caused by Beirut blast

Luis Batalha calculated the magnitude of the blast using a video that was being shot at the time of the incident. The video featuring the bride all dressed and the way her wedding dress moved with the shock wave is how he calculated near to the exact energy that was generated due to the explosion.

The recent Beirut explosion shook the world and devastated entire Lebanon’s capital. Among all the relevant media, a video surfaced from ABC News of a bride having her wedding photoshoot disrupted by the explosion. A physicist named Luis Batalha stated that he calculated the energy of the Beirut Explosion using the displacement of the wedding dress in the video. The posts have gained him a lot of attention.

Here is how Batalha estimated the energy of the explosion: “The energy released by an expanding gas across one direction is: E=Fd=PAd=P?V To calculate the volume displaced (?V) we use the displacement of the wedding dress~2m. This means that the amount of the spherical shell of displaced air was: ?V= 4?d²r =4?(1400m)²(2m)

Knowingly, the pressure of the compression wave in the air is approximate, 10³N/m², we calculate the energy of the shock wave E_wave=P?V. Taking into account the efficiency of the explosion, we estimate that the power of the blast was approximately ~100 tons of TNT.

This method was used by Enrico Fermi to determine the energy of the first atomic bomb explosion (Trinity 1945 – 20 kilotons of TNT). He threw a few pieces of paper in the air and measured the displacement.”

One of Batalha’s followers was quick to point out that the distance of the bride from ground zero was unknown to which the physicist replied that he identified where she was thanks to a sign on the store behind her. “That’s how I calculated that she was 1400 m from ground zero.”