Baking a cake is pretty easy: mix flour, eggs, and other stuff, and the batter bakes into spongy cake. But baking bread is trickier. You have to use “yeast,” which is a fungus (like mushrooms — weird!). Yeast is alive, and if you “feed” it by sprinkling warm water on it, it will grow and make your dough rise into fluffy bread. Once you mix it in with the flour and other ingredients, you let the dough sit, and it “rises”: it actually gets bigger (our Hello Kitty ruler helped us measure). You then “knead” the dough, or mash it with your hands, to squeeze the air bubbles out. We then wrapped our dough into cinnamon rolls, which then poofed up even more before baking. Try making bread dough and twisting it into loaves, pretzels, or these yummy cinnamon rolls (recipe here) — beware, it’s hard to eat just one!
Wee ones: These cinnamon rolls are round like circles. See if you can spot 3 circles in your room.
Little kids: If you make 8 cinnamon rolls and you eat just 1, how many are left? Bonus: If the dough starts off 3 inches thick in the bowl, and ends up twice as thick, how many inches did it rise?
Big kids: If your bread has to bake for 45 minutes starting at 5:20 pm, will it finish in time for your party at 6 pm? Bonus: If instead you bake a tray of 36 cinnamon rolls lined up in 4 rows, how many are in each row?
Answers:
Wee ones: Answers may include a clock, a toy ball, buttons, and shoelace holes.
Little kids: 7 rolls. Bonus: 3 more inches.
Big kids: Not quite — it will finish at 6:05 pm! Bonus: 9 rolls.
Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.