I helped out with a bread and yeast experiment in my son's class at school last week. I started off by having the kids grind their own whole wheat flour by hand. Then they added the remaining ingredients to a heavy-duty one-gallon ziploc bag, sealed it and took turns kneading the dough in the bag--one regular-sized loaf per bag for each group of four students.
Next we divided the dough into four pieces and they each shaped their own mini-loaf. We placed them on parchment-lined baking sheets to rise and I wrote their names on the parchment next to each loaf so they'd be sure to get their own loaf back. While the bread was rising, they helped me make a batch of blackberry and blueberry freezer jam.
Another mom did a demonstrated mixing yeast, sugar and water in a flask and placing a balloon over the top. They took measurements at intervals as the balloon filled with carbon dioxide.
When the loaves had risen, I took them all home, baked them and brought them back for an afternoon snack of bread and jam. The students were so proud of themselves! One girl commented that it was "almost the best bread she had ever eaten!"