This is what we do in our school. I know there are many different ways to go about this. Some schools hav an extra practical skills class all year long in third grade. We devote 2 weeks of main lesson time (or ten mornings total, if two weeks can't be done consecutively) to the fiber block. I usually introduce the task, and then have another project.
An outline of the block:
Day One: Wash a raw fleece, make felt balls
Day Two: Card the fleece, make felt balls with the fleece we carded being in the center
Day Three: Spin with a drop spindle in pairs, make God's Eyes using bamboo skewers and embroidery floss
Day Four: Spin with a drop spindle individually, make God's Eyes with three sticks instead of two
Day Five: Make small skeins of yarn, dye with synthetic dyes
Day Six: Warp a small card, begin weaving a pouch (the project is found in The Children's Year), spinning wheel introduction and drum carder
Day Seven: Continue weaving, felt a small pouch
Day Eight: Continue weaving, sun dyeing in jars with natural dyes
Day Nine: Finish weaving the pouch, finish sewing it up, butterfly cord and/or braiding a strap
Day Ten: Make a flat felt, review,
When I went to the handwork conference, I spoke to another handwork teacher who introduced vocabulary words and also some math in weighing wool, measuring, etc. This really inspired me, although I was not able to integrate much of what she was doing this year, except I did have my class write a thank you note to the shepherdess who generously gave us our Shetland fleece, and they included some of the terms they'd already learned. I haven't come up with a comprehensive list yet, but there are so many spinning and sheep words they can learn.
In introducing this block, we talked about all the different kinds of fiber, and what our clothes are made of. They looked at each others' tags and we discussed which was from plants, which from animals. I showed them pictures of different sheep. They got to take a field trip to Shaker Village, where they saw all kinds of plant dyeing and a sheep being shorn, and tools for spinning flax, along with looms and other fiber equipment.
I higly recommend the book, Unraveling Fibers. If you have never done any of these things yourself, I recommend going to a fiber festival and acquainting yourself with a few sheep farmers. You can also try localharvest.org to find a fleece or a sheep farmer near you. Visit a sheep, by all means! Get in touch with the local spinning guild and see if anyone there does teaching or demonstrations to children.
If you are experienced in this, please feel free to share what you do with the children. I am going to write a bit more on the details of what each class is like, each day. Tomorrow!