Animal Communication Through research on how animals communicate, I can explain how sound vibrations are carried by waves through air, water and other media. SCN 2-11a

Discover the differences in hearing between humans and other animals Understand the limits of human hearing Consider how sound behaves in solids, liquids and gasses And we will… Be able to define ultrasound and infrasound Be able to explain why sound travels at different speeds in different materials Be able to describe a range of different reasons for animals communicating using sound. Today we are going to …

We already know that sound is a form of energy and a vibration… Today we’re looking at how it travels, in things called… … waves

What waves have you heard of before? If you were to draw a picture of a wave, what would it look like?

We can look at the patterns of sound waves on devices called Oscilloscopes Oscilloscopes produce wave patterns like these… …on devices which look like this.

There are lots of different parts to a wave pattern we can see… The red line shows the Wavelength The green line shows the Amplitude

The blue line shows a low frequency wave. The red line shows a high frequency wave. The frequency of the wave is the number of complete wavelengths that are happening in a set time.

Why does this matter? The pattern of the wave tells us about the sound. A high frequency means the sound will have a high pitch – like a mouse squeaking! A low frequency means the sound will have a low pitch – like dog growling!

Why does this matter? A big amplitude means that the sound is loud – like a lion roaring! A small amplitude means that the sound is quiet– like a cat purring! The pattern of the wave tells us about the sound.

Different animals including ourselves – can only hear certain frequencies of sounds.

Sound that has a very high frequency is called ultrasound. Dolphins are an example of an animal that can hear sounds at ultrasound frequencies

Sound that has a very low frequency is called infrasound. Giraffes are an example of an animal that communicates in infrasound.

How does sound travel? Please stand up and get into a space where you can’t touch anyone…

The air is made up of… …molecules that are not… …packed closely together… …Like how you’re standing just now!... …this means that it takes time for them to bang into (vibrate with) each other

Please move a little bit closer together…

Liquids, like water, are made up of molecules that are slightly closer together… which means they can bang into each other (vibrate) more easily.

Please stand in little lines, altogether - shoulder to shoulder!

Solids, like metal, are made up of molecules that are packed closely together… which means they can bang into each other (vibrate) very easily.

This means that sound can travel most effectively in solids, then liquids, then gases!

Today we have… Learnt what sound wave patterns look like on oscilloscopes Learnt the names of different parts of a sound wave Learnt what sound waves will look like for different pitches and volumes of sound Learnt about the range of animal hearing Learnt how sound travels in solids, liquids and gases