Earth & Conservation

What Is The Speed Of Light?

In Einstein's famous equation E=mc2, did you know that the "c" stands for the speed of light? So what is the actual speed of light? You may be surprised that it's not always a constant.

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What Are Stars Made Of?
What Is a Light Year?

More TestTube 101
What Are Stars Made Of?
What Is a Light Year?

TestTube 101 is here to quickly answer all your everyday questions about space, chemistry, physics, biology and more. We've got new videos daily, so keep coming back! Do you have a science question you'd like to get answered? Leave it in the comments below.