Eggs that you buy from the store will not stay fresh for long  without refrigeration. Eggs that come right from the chicken can  kept at room temperature for weeks. Store bo â¦ ught eggs should be  refrigerated within a few hours of buying them just to be safe.ven with its natural (but easily cracked) calcium-carbonate container, a hard-cooked egg is a perishabl â¦ e food, so it shouldn't be kept at room temperature for more than two hours.   If kept in an unbroken shell and in the refrigerator about a week.
The human range is commonly given as 20 to 20,000 Hz, though there is considerable variation between individuals, especially at high frequencies, and a gradual loss of sensitivity to higher frequencies with age is considered normal. Sensitivity also varies with frequency, as shown by equal-loudness contours.
Frequency is measured in hertz (Hz). A person who has hearing within the normal range can hear sounds that have frequencies between 20 and 20,000 Hz. The most important sounds we hear every day are in the 250 to 6,000 Hz range.Speech includes a mix of low and high frequency sounds:requency is measured in hertz (Hz). A person who has hearing within the normal range can hear sounds that have frequencies between 20 and 20,000 Hz. The most important sounds we hear every day are in the 250 to 6,000 Hz range. Speech includes a mix of low and high frequency sounds: