Here's why:
* Short vowel sounds are typically found in words where the vowel is followed by one consonant.
* Long vowel sounds are usually found in words where the vowel is followed by a consonant and a vowel, or by a double consonant.
In the word "bow", the vowel "o" is followed by the consonant "w". This indicates a short vowel sound.
The "o" in "bow" makes a similar sound to the "o" in "hot" or "cot".