The Mind Reading Game is from Jolly Music Handbook for Beginners by Cyrilla Rowsell and David Vinden, where it is known as the Signals Game.
Move away from the keyboard and tell the student they’re going to play a mind reading game. Tell them it is very tricky and they probably won’t be able to do it.
Sing “Stand Up” on so-do’ (eg E up to A) and then “Sit Down” on so-do (eg E down to A). Repeat, sometimes repeating the same instruction twice or more in a row.
Wow! You’re amazing!
Look impressed. They are really good at mind reading! How did they know what to do? They will probably answer that you told them what to do. Sometimes a student may notice immediately that you altered the pitch of your voice. Then you can be properly impressed!
Roll your eyes and say oops! OK, I won’t do that this time. Repeat the game, singing “doo doo” instead of the words, but move your arms up and down with the pitch. Remember to try and “trick” them by repeating the same instruction. Again, be amazed they could still do it and ask them to explain how. They will tell you moved your arms and you can roll your eyes again at your folly! They will think this is hilarious.
This time sit on your hands and just sing “doo doo”. Some students will now struggle. If they do, quickly go back to the arm movements until they are more confident. If they can still do it, they might be able to tell you that you changed the sound of your voice. Some might say high or low, or even use the word pitch!
This game should be repeated each lesson until you determine it is no longer enjoyable or beneficial. You can make it more difficult by reducing the interval to so-la and so-mi but I only usually do this with my singing classes. If you teach shared lessons you can all hold onto some lycra and lift and drop instead of standing and sitting. This way the stronger students can help the weaker ones make the connection.
Finally if they are still struggling you can put it onto the piano, use the very lowest and the very highest keys. Just make sure they don’t confuse high and low with loud and soft, or just have the terminology the wrong way round. Some games on the piano may help here. Show how sounds can be loud or soft, even on the same pitch. Talk about different animals or different people using higher or lower voices.