you will find me in Mercury, Earth, Mars and Jupiter, but not in Venus or Neptune. What am I?

I can rush, be still, be hot, be cold, and be hard. I can slip through almost anything. What am I?

What can go up and come down without moving

What is the center of gravity?

What is full of holes but still holds water?

It is impossible for me to be created, and I can never be destroyed, I can only change form. What am I?

Many have heard it, but nobody has ever seen it. It will not speak back until spoken to. What is it?

“I am red but I am not a strawberry

I have different types but I am not an apple

I can be pumped but I am not a bicycle

I can be donated but I am not money

I contain cells but I am not a jail

I am in your body but I am not your heart”

When getting someone’s attention

This is what you might try to catch

And if you’re a pirate at sea

It might be covered by a patch

I can hold things but I’m not a bag

I’m used to write things down but I’m not a pen

I have digits but I’m not a cellphone

I have nails but I’m not a hook

I’m part of your body but I’m not a foot