No cool name for it, but tonic water looks clear in room light and glows blue under black light. Might be something to be done with that. Add some white powdered laundry brightener /whitener and you can intensify the glow.
Get some of those dehydrated silica gel balls. They start out the size of BB’s but swell to the size of shooter marbles in water. When you leave them in water, they blend so well as to be invisible. Maybe they could be the eggs of some invisible creature. Also, if you hydrate them in tonic water, they will glow in black light like the tonic water. Might serve as a way to detect them.
Since it appears there will be vinegar included, you might consider bits of limestone (or similar) that kinda fizz up when the vinegar is poured over them. Example that is just over a minute long.
Also, it might be rewarding to search youtube for things like “household chemical tricks” (etc). I’ve seen lots of neat stuff there. It can be productive to look around the suggestions shown after video finishes, too.
Very cool you are doing this, emm!
Not necessarily cheap and probably be too dangerous to use unsupervised. Do your own research and make your own judgement.
Flameless ration heaters are available for military MREs. Add a bit of water and they dramatically heat up, producing hydrogen gas and other, stinkier components in the process. I’m not sure of the specific chemical formulation but at least some of them use a finely ground alloy of iron and magnesium. This powder is mixed with ordinary table salt. Add water and the salt dissolves. You now have bits of iron/magnesium alloy floating in an electrically conductive solution, essentially forming thousands of tiny, short circuited batteries.
First of all, you’re an awesome parent.
When I was a kid my mom got ahold of these glitter stars (like confetti) she would hide around the house and I was super in love with finding them. Maybe something like that with a story about them being real stars pulled from the sky.
But along the lines of pool testing chemicals, pet stores sell all kinds of reactive agents for use in fish tanks. That could be fun.
Third mention, one-third credit. Um… [math break] 333,333 1/3 points for you!
Ha! Not suited for the potion kit, but I think we may try that as a separate activity sometime. Snot is indeed HILARIOUS and DNA is cool not only because of its association with superheroes/supervillains but also because we watch Cosmos with the kid as a treat on pizza nights, and there’s DNA right in the opening credits (and a few of the episodes). Thank you!
Hmmn, all interesting ideas I may develop, though I may skip the nail polish, as it would inevitably end up in his hair or something. At least four points each for three out of four suggestions, plus an awesomeness bonus for so many at once, means you get… at least twelveteen points! Maybe more! Could be huge, could be huge, of course I would never say that, other people are saying that, very big, very very big points here is what they’re saying.
:dubious: OK there, buddy, I’m on to you now. You’re an eight-year-old boy, aren’t you? You want to conspire with my kid make an utter mess of my house and/or yard. Don’t deny it. Well, I’m on to you. We’ve done slime here, and we’ve done ooblek, and I have the Superfund sites to prove it, and I am wise to those tricks now!
OK, definitely getting some of those — I saw some at the dollar store recently —
— oooh, and these are great embellishments. The two of you jointly earn supermaxbonus points!
Another great standalone! Maybe especially good for Independence Day, when it doesn’t get dark until well after the appetite for fireworks kicks in and an appetizer is called for. I hereby mention you all honorably.
Seriously cool, but I would not yet trust this particular eight-year-old with anything that might make a real mess if it leaked. His room gets messy to the point of impassability, and things go crunch when you try to walk to the laundry hamper. I’ll put this on the list for a couple of years from now.
You don’t even need the open flame. When we did the lemon juice writing as kids, we’d wave the paper in front of a light bulb to heat it. (An incandescent bulb, of course, because that’s all there was.)
More excellent suggestions for future kits!
And, of course, we don’t have any of those left in the house. I can’t offhand think of any similarly safe source of mild heat available to us in the summer. But in the winter, he could hold it up to the woodstove, so I’ll mark lemon-juice ink down for the Christmas refill. Thanks!
You’ll be back for more advice–he’s going to need a familiar, eventually. 
:eek:
Also:
Special Ribbon for Gentlest Correction of a Teeming Millionth goes to Chronos!
Let’s see, for approaching the bleeding edge of acceptable, how’s about…
Or, if you happen to have a black light,
•Invisible ink! Or
•Luminol! Also available in handy spray form!
Sorry, missed this earlier. I think his neighborhood friend’s family has a little inground pool (where the neighborhood kids bring all the frogs they liberate from the swamp down the street) and they might have some test strips for it, not sure. If not, I’ve seen pool strips at one of those cheap-stuff Big Lots stores in town. Great idea! I might even actually splurge on regular pH strips and put in something written, something pseudomagical/quasiscientific about acids and bases (after the apparently necessary Wikipedia refresher course for me :smack:).
How many points is that? Gosh. Lots! Maybe a jillion?
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[li]:eek:[/li][li]:eek:[/li][li]:eek:[/li][/ul]
Either I figure out how to get them (safely) into this kit batch, or we get these all for side projects. ONE ZILLION POINTS FOR YOU
I have some tiny glitter stars that I think I will label in just such a fashion! Hmmn, weren’t there animate fallen stars or something like that in Howl’s Moving Castle? Multiple literate realities for the win!
BTW, the kid at least claims to still believe in the Tooth Fairy. She leaves very tiny (6-point font), chatty, formal letters under his pillow, along with the single golden dollar coin she gives for each tooth, and she also accidentally leaves a little trail of the powdery glow-in-the-dark glitter that it turns out is simply a byproduct of her profession. I’m pretty sure that glitter is why he still believes — either because it’s sufficiently convincing, or because it’s just too awesome to have it under your pillow to risk revealing disbelief.
Oooh, I’ll look into that!