I think it is always best to demonstrate this activity first in a Phonics circle time so the children know what to do and what sounds they are learning, and then after that it can be left out in an area of the classroom for children to access independently. First get the children to say the three letters you are focusing on, and then get them to name each of the pictures. Encourage the children to discuss with talk partners which picture starts with what sound, and then ask children to choose the pictures one at a time and place them on the correct letters.
As an extension , ask the children if they can think of any other things starting with a particular letter and if they can then they can draw a picture of it on the paper (eg – if they thought of a snake for something starting with ‘sss’ they can draw a snake on the piece of paper showing a ‘s’).
Other ways to lay out this activity are to use big maths sorting hoops, with letters in the middle of each, or to use actual objects instead of pictures (although this takes a lot of collecting!)
What initial sounds activities have worked well for you recently? Please share in the comments below…