Answer:
I sleep when you are awake, I am awake when you fall asleep. I can fly but no feathers to aid my flight. What am I?
I climb higher as I get hotter. I can never escape from my crystal cage.
The letter S is added to pluralise most words in the English language. eg. Letter to Letters Word to Words and Language to Languages. But I am a word that is pluralised with the addition of the letter C.
Lighter than what I am made of, more of me is hidden than is seen. What am I?
Of the king I am blue and of the peasant I am red. Of the frog I am cold and of the dog I am hot instead.
I go in hard, come out soft. Blow me hard and I'll make a pop. What am I?