Question

the book asks for the vowels
circle the vowel spellings

Does this mean the vowels?
coin = oi

please = eae

Answer 1

Yes, all those are vowels, whether they occur singularly or in pairs, whether they are silent or pronounced:

bear = vowels are e and a
hopped = vowels are o and e
etc.

Here are some definitions of vowels on different websites:

http://www.usingenglish.com/glossary/vowel.html
(...for people learning English as a second language, but the explanations in this website are excellent.)

http://www.kidzone.ws/kindergarten/vowels/index-short-vowels.htm
(...for very young children)

http://en.wikipedia.org/wiki/Vowel
(VERY complicated explanation!!!)