I prefer to eat spareribs that have been scrupulously trimmed, with the breastbone and the floppy section (the skirt) removed. Sometimes this is called St. Louis–style trim. If your butcher won't do this for you, find an instructional video on YouTube. There's a lot of meat in the skirt, which can be braised with a can of tomatoes – in the slow cooker, if you like – to make pasta sauce.
Kids can measure rock sugar and sniff star anise, and if they're ready for liquid measures, let them measure the liquid ingredients. Scallions are hard to cut all the way through and are therefore not ideal for learning knife skills.
Place all ingredients in a slow cooker and cook on low heat 7 to 8 hours or until the meat is very tender.
Note: Rock sugar is crystallized sugar similar to rock candy, sold in Asian groceries. It comes in irregular light-brown pieces or in gem-shaped clear rocks, and it may come in an opaque box so you can't tell which you're getting. Luckily, either is fine.