high frequency sound on a tv advert

A dog food company has launched the first TV advert aimed directly at dogs themselves.  The advert’s soundtrack includes sounds with frequencies in the range 18 000 to 20 000 Hz (18-20 kHz).  Dogs can hear sound with frequencies greater than 20 kHz, we call this ultrasound.

I found a copy of the advert on Youtube.  The upper limit of human hearing is 20 kHz, so some young people should be able to hear the sounds for themselves even though adults can’t.  Can you?

Now let’s see what happened when the BBC Newsround team filmed some dogs while the advert played in the same room.

You might have used a signal generator in class to discover your personal upper frequency limit.  The video below has a soundtrack that starts at 1 Hz and sweeps up to 20 000 Hz, before sweeping back down to 1 Hz again.  For how long can you hear the sounds?


four things everyone should know about quantum physics

We’ve just started to look at the parts of unit 1 we left behind in November.  The first of these is Quantum Physics.  It’s a strange topic and you might want to stick your head in the sand of classical physics and seek refuge in waves.  Luckily, Prof. Chad Orzel has come to our rescue with a blog post called Four things everyone should know about Quantum Physics.

Prof. Orzel is also the (co)author of a book called How to teach Physics to your dog.  I’ve not bought it yet but the free download of chapter one (use the link below) mentions some of the ideas we have looked at already and mentions some names that should be familiar by now: Einstein, Planck, de Broglie (is that picture of de Broglie wrong, looks like a young Einstein to me?) and Millikan.

Have a read of the introductory chapter and share it with you dog. The interview is good too.