An interesting statement about ultrasound

 I bought a new ultrasonic scarer for mice. It is interesting to note that cats and dogs can hear some ultrasound but that this is pitched too high for them.

Most physics teachers would be aghast at that the statement that "ultrasonic waves behave in a similar way to light": hey! Ultrasound is a longitudinal wave and light is transverse - it's  a bad source of exam confusion. But hold on! Actually, the point being made here is that ultrasound will not travel through objects either. Given its use in pregnancy scans, it would be understandable if people thought it was. You need saline gel to get the ultrasound to go into a body and that only works because the speed of sound in saline gel is the same as in muscle. Even saline gel would probably not get ultrasound into furniture - and it would be messy....