Younger offspring: I drew this picture of the Earth!
Dr. Free-Ride: Wow, that’s quite a picture. Will you tell me what’s going on in it?
Younger offspring: Yes, but first scan it in.
Dr. Free-Ride: Hmm. Is it maybe not a coincidence that you’re bringing home a picture like this on a Thursday night?
Younger offspring: That’s a really tall volcano. And over there is a smaller volcano — for grilling stuff. 
Dr. Free-Ride: I see. What else is there?
Younger offspring: On the other side of the tall volcano is a meteor coming toward the Earth, and right under that is a meteor-catcher.
Dr. Free-Ride: That’s very convenient. What are those between the meteor-catcher and the tree?
Younger offspring: That’s the Moon.
Dr. Free-Ride: Are there lots of moons here?
Younger offspring: No, that’s the same Moon in different places at different times. The one right next to the meteor-catcher is the Blue Moon. 
Dr. Free-Ride: Interesting.
Younger offspring: And this is the ozone. It has some big holes in it.
Dr. Free-Ride: Do you know what the ozone does?
Younger offspring: (Pauses for a moment with furrowed brow) It gives the Sun ultraviolet radiation.
Dr. Free-Ride: Really?
Younger offspring: Ultraviolet radiation is what gives you sunburns.
Dr. Free-Ride: That’s right.
Younger offspring: The Earth doesn’t give us sunburns, only the Sun does, and the Earth has to get the ultraviolet radiation from somewhere.
Dr. Free-Ride: I think it’s more complicated than that. The ozone layer is almost like … a sunshade. If you’re under part of the sunshade with a hole, more of the ultraviolet radiation gets through.
Younger offspring: So we need to wear sunscreen.
Dr. Free-Ride: Sounds good to me.
Younger offspring: The ozone is holey like Swiss cheese.
Dr. Free-Ride: But probably not quite as melty.
 The sprogs have been reading The Little Prince lately. Apparently, the title character of that book does some grilling with volcanoes.
 The “Blue Moon” is the second full moon in a calendar month. Usually, it isn’t actually blue in color.
And, you can take an online Ozone Hole Tour, which will give you information about what the ozone layer really does.