Physics Riddles

It keeps you on the ground and stops things from floating around. What is it?

I am the first you ever saw, what greets you every morning and what goes out in the end. What am I.

Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers, magazines, and journals. What am I?

What is the center of gravity?

I come in many shapes, sizes, and colors. I stick to many surfaces but I am, in fact, not sticky at all. What am I?

How does Einstein begin a story?

Many have heard me, but nobody has seen me, and I will not speak back until spoken to. What am I?

Looks like water, but it's heat.
Sits on sand, lays on concrete.
People have been known,
To follow it everywhere.
But it gets them no place,
And all they can do is stare.

Lives without a body, hears without ears, speaks without a mouth, to which the air alone gives birth. What is it?

You saw me where I could not be.
Yet, often you see me.
What am I?

What cannot talk but will always reply when spoken to?

Many hear me, but no one sees me, and I only speak when spoken to. What am I?

I can fill a room but take up no space.
Look out at night, and I am in no place.
What am I?

Be sure to shout for its answers are weak, but there is no language it cannot speak.

Some people avoid me, some people count me, some people just consume me. What am I?

Use me if you really want to see inside someone. What am I?

I can fill any space, float, and disappear. Never touching the ground I help others get around. What am I?

You can see me in water, but I never get wet. What am I?

Where does bad light end up?

You can see nothing else when you look in my face,
I will look you in the eye and I will never lie.
What am I?

You heard me before, and then again. Afterward I die, until you call me again. What am I?

I am what bring things together. Without me everything you see would be a total mass or debris everywhere. What am I?

The higher I climb, the hotter I engage. I cannot escape from my crystal cage.

What looks back but cannot see?

What can go through glass without breaking it?

I only exist when you are here. Where you never were, I can never be. What am I?

Hearing something unexpected or touching a live wire can have this effect.

Before I came, the world was darker, that's true. But beware, I can also kill you. What am I?

Makes apples fall from trees.

What can be measured but has no length, width or height?

What is the name of the first electricity detective?

Why can't you trust an atom?

How many theoretical physicists specializing in general relativity does it take to change a light bulb?

I drift forever with the current and flows to your everyday life. I make living easy but I am good at killing people too. What am I?