After children learn the basics of phonics and the letters sounds (phonemic awareness) you can move on to learning about the tricky vowel sounds called diphthongs. A diphthong is a single-syllable vowel sound in which the beginning of the sound glides to another, slightly different vowel sound. For this reason, diphthongs are often referred to as gliding vowels. For example - (OI/OY). (OU/OW). (EE/EA/IE). (AW/AU). Kids can read the challenge and determine the correct spelling and clip the clothespin on their answer. The back of the card has a star showing the correct answer so they are self-checking for independent practice or work stations in the classroom. Includes: 50 challenge cards with answers on back. Cards are 5" x 4". Includes 5 Clips which are 2.25" x 1.5". Includes a sturdy storage box - 5.5" x 4.5" x 1.5" Perfect activity