The lesson looks at the two theories of the universe being created - Big bang and steady state.
They use the key cards and split between inferences and observations then use them to decide which is a better model and why
Use rulers to demonstrate amplitude and pitch. My starter was me playing happy birthday with a 15cm ruler, and Jingle Bells (it was December when I planned this)
Practical activity.
In pairs students pick a type of ear to make. They then stand near the sound source that is included and walk backward until they can no longer hear the sound. The sound needs to be very low, along with the class being quiet.
Two elephant ears should be the best.