I like to use some of the pictures that include sound but the speaker icon is too small and it is also distracting. Therefore I choose to make the object create the sound.
Try getting one of the sound images from the Gallery.
Select it and click on the drop down menu.
Change the option from corner icon to object.
Click on Attach Sound.
You now have a larger surface that produces sound and children can experience cause and effect. You might get them working on which thing makes sound!