What is the difference between radioactive decay and radioactivity?

An unknown radioactive element decays into non-radioactive substances. In 180 days the radioactivity of a sample decreases by 33 percent. (a) What is the half-life of the element? half-life (days): (b) How long will it take for a sample of 100 mg to...

How can I tell the difference between a natural radioactivity and a induced nuclear reaction when it comes to equations for nuclear reactions.

How do you know the difference between the pain caused by tooth decay, sensitive teeth and sinus pain? I have a pain in the area of my face on the top left hand side about halfway back. It's not too bad but is there a lot of the time but doesn't get...

I understand that most heavy nuclides are radioactive, and that only radioactive molecules can undergo decay. Is that correct so far? So why is carbon-14 used for dating? Isn't the molecule too small to decay? Decay: When they emit alpha particles, or...

My best friend has had some issues on his back molar, which has led to some decay. The dentist says that odds are he'll need a root canal (they've even given him literature on it), but they won't know until they get in? How does this work? Does the filling...

I'm not suggesting eating youghurt INSTEAD of brushing your teeth. Brushing and flossing are OBVIOUSLY the best approach to taking care of your teeth. But there are times when you're on the go and can't stop, etc., when you need a snack or light lunch...

Does nobody realize that these popular graphics about radioactivity misinform people? You can see in their charts: 'for a year', 'for a day', 'one day dose', 'yearly'... Either compare all radioactivity doses within the same time frame - say for a year...