Teen-age children as experimental subjects

We always enjoy home science experiments and it was fun the other night to learn about a new experiment we could try with our teenage daughter and an iPhone.

As it turned out, the joke was on us.

My husband is an enthusiastic fan of the iPhone store. Last night, he downloaded this application called "Army Knife."

This application has, I kid you not, the following nine items:

  • unit converter - these are always helpful, especially if you travel
  • ultrasonic whistle
  • protractor
  • Heart (beats per minute) counter
  • measuring tape
  • digital caliper
  • Two levels
  • flashlight
  • emergency SOS light

Some of these are amazing enough to consider, when you realize you're doing this with a phone. I mean, a tape measure?

It works, though. And, if you happened to be out shopping and wondering what would fit where, you might not have a tape measure, but you would most likely have your phone.

That's all fine and probably useful, but we found the ultrasonic whistle to be the really fun way to spend some time. The whistle makes noise at different frequencies and supposedly you can only hear certain frequencies when you're below a certain age.

That's a challenge that's hard to resist.

After making sure we couldn't hear those different frequencies, we tried our dog.

Figure 1. Koko pays attention. The cats continue sleeping.

This wasn't a good experiment since the dog tends to notice us hovering around her and looking for a response. It only took a moment before she got really excited and brought her toy, just in case we wanted to throw it somewhere. I mean you never know. We really might want to grab a slimy spit-sodden stuffed animal and throw it down the hallway for the dog retrieval game. We might or we might think first. Retrieving toys can be an infinite loop process with our dog.

On to our child. My husband set the phone on the proper frequency and tiptoed upstairs.

"What's that noise?!!" she cried, exasperated and a bit perturbed by his grinning face.

"Oh you hear it!"

Yeah, of course. (translation: how you be so stupid, of course I hear it)

It's playing a special frequency! Isn't that cool?

Oooooh (long sigh, extremely bored, exasperated look). OMG! I can't believe you don't know about that!


Dad! People have been using those sounds as ring tones for years!! Where have you been?!! We use them because teachers can't hear them!! How could you not know that?!!

(look of shock on parental faces)

And Parents, no one over 30 Twitters, okay?

OMG, I can't believe it.

More like this

I don't think I've commented here before, so:

First, I love your blog, for many different reasons. Keep it up!

Second, this made me laugh out loud. Science-y parents devising and executing iPhone-based experiments with, variously, pets and children. :D

I think the test with your dog would be to start with a conditioned response she already knows, for example, "Sit!" Play the sound while you give the command, and then offer the usual reward (praise or treats). Eventually, the dog should sit when she hears the whistle alone.

You could then apply the same methodology to your daughter by playing the tone whenever you ask her to take out the garbage or wash the dishes. Eventually, you should be able to play just the tone and have her blurt out, "Ugh! Why do I have to do everything around here?"

Ha. I am 29 and I can hear those irritating high-pitched noises.

By fullerenedream (not verified) on 06 May 2009 #permalink

I'm 41 and I can hear them.

Martin - you might be surprised. The iPhone program has a few different frequencies and different age ranges. There are probably some you can't hear.

I'm 46 and can hear them.

But then, I've always had good high range hearing.

By Benjamin Franz (not verified) on 06 May 2009 #permalink

I too had know about this for years, being the sort of dad who keeps up to date with latest Y-Gen stuff and still goes out to music festivals. However to my great delight I recently discovered an mp3 comprising a lovely 15kHz tone. I can quietly hear it so I know it's on although my teenage children can well and truly hear it, especially the annoying 17yo daughter. My experiment went something like this.

Me:"Hey listen to this" (Plays sound quietly on mobile phone, setting up the control condition)
Daughter: "Yeah, big deal dad, everyone knows about that, we use it on our ring tones, get a life.." (said in a rather dismissive and annoying tone)
Me:"Yes, I know you do but listen to this" (Plays sound through sound card on computer with every volume control set to maximum, setting up the experimental condition)
Daughter:Aggggghhhhh..turn it off! (Hands clamp to ears, starts groaning and doing a weird epileptic style dance around the kitchen for 10 seconds)
Me: "Pretty rad eh?" (said in an annoying Gen Y tone of voice)
Me: "What, this..." (hand moves mouse over play icon, repeating the experimental condition)

That's the problem with Gen Y, I fear they are loosing their ability for creative thinking nor do they appreciate the benefits of experimental science. To me it was simply the obvious thing to do, see how loud you can make something.
Seemed a bit novel to the kids. :-)
This delightful tune has somewhat restored the power balance within our home.


In the UK, some of the subway stations do just what you did to deter loitering by teenagers. Those high frequency tones really are a double edged sword.

By Breton bienvenue (not verified) on 08 May 2009 #permalink

Ugh, that tone is like the noise that the TV makes when it's muted, which has driven me crazy for years! It makes my ears ring, and I'm 30.

Animal testing followed by human testing. Perfectly logical. Didn't know about the phones being used so teachers can't hear them though

By Richard Eis (not verified) on 11 Jun 2009 #permalink

That reminds me of someone I used to work with who had done a lot of high power ultrasonics work in the past. He said it wasn't true that you couldn't hear 40 kHz, you could hear it if it was loud enough. He had worked with ultrasonic whistles that generate 180 db at the focus. If you put a ball of cotton there it would catch on fire.

His hearing was totally trashed.