 This is how I teach measurement by size. In working in a small group of two or three children of ages maybe three and four, I have a box that has different length pipe cleaners. If I'm outside in nature I'm okay with using sticks or leaves or anything else that might be of different size and length. So first I have a student draw one of the pipe cleaners and put it on the table and then I have my second student draw one out of the box and put it on the table and then I will ask them which one is long and then I can show them if that's a new vocabulary word and I can say this one is long and then I will say which one is short and they will come to it and they will point at it and go this one is short and I will be very happy for them and then we will start over and try again and then we'll draw a new one out of the box and we'll put it on the table and then the other student will draw one from the box and put it on the table and I'll ask the same question again which one is long and this time I'll let the kids answer without my help and so they'll tell me the brown one is long and they can tell me this one or the white one is short. What's nice about this activity is you can also have a third student if you're working on comparing by size and then we can work on long, longer and longest. So this one can be long, this one can be longer and this one is the longest and then we can start all over again practicing those words.