earth
what is visible but is impossible to touch or feel?
Clouds
what is impossible for humans to hear but dogs can hear?
a dog whistle.
what is green and is food?
lettuce or vegetables
what changes every minute but can't go back?
the time.
what is bright and can blind you?
the sun.
what is hot but has no shadow?
a flame.
what has all the space and has tiny lights?
outer space.
what do some people call boring but is required?
School.
what turns warm on one side but when flipped over turns cold.
a pillow.