Super idea for word work: missing bottle cap vowels! Looks easy to DIY. Would be great to add a recording sheet with only the pictures and have kids write the whole word, then underline the vowel. Putting this on my to-do list.
A simple song and video to help practice short vowel sounds. When young children begin to learn how to read three letter combinations (CVC), it really helps to learn with a song :) I hope this song and video are of some use to you.