You may have wondered how we came up with the recommendation that women have 500 calories and men have 600 calories on a Fast Day. We used the rule of thumb that women need 2000 calories and men need 2400 calories per day and on a Fast Day you should eat a quarter of a normal dayâs recommended calories. Some of you have also wondered exactly how many calories you should be eating on days when youâre not fasting.
According to most sources, the human hearing (frequency) range is between 20 Hz and 20,000 Hz (bats can hear up to 100,000 Hz!). What does that mean? Sound is a mechanical wave that propagates through a medium (air, water), and the frequency of a sound wave determines its tone and pitch.
From the pinna to the tympanic membrane, sound is increased by 5 to 15 decibels (dB) in the 2,000 to 4,000 Hertz (Hz) range due to the resonance of the auditory canal. The human ear is most sensitive to sound within this range and most vulnerable to damage from noises that are too loud.