Here's why:
* Short vowel sounds are typically found in words where the vowel is followed by a single consonant. For example, "cat," "dog," "sun."
* Long vowel sounds can be created in various ways:
* Vowel digraphs: Two vowels together, like "ee" in "see" or "oa" in "boat."
* Silent "e" at the end of a word: Like "bike" or "cube."
In "bubble," the "u" is followed by the consonant "b," but the "e" at the end of the word makes the "u" long. This is a classic example of the silent "e" rule.