Here's why:
* Short vowel sounds are typically found in words where the vowel is followed by one consonant. In "nest", the vowel "e" is followed by the consonant "st".
* Long vowel sounds are often found in words where the vowel is followed by a vowel or a silent "e".
Therefore, the "e" in "nest" makes a short vowel sound, similar to the "e" in "bed" or "pet".