Here's why:
* Short vowels are typically found in words where the vowel is followed by a single consonant. Think of words like "cat," "dog," "hop," "run."
* Long vowels are often found in words where the vowel is followed by a consonant and a silent "e" at the end, or by another vowel.
In "steak," the "e" is followed by a consonant ("k") and a silent "e" at the end, making the "e" sound long.