Bread has flour and water in it. Matzah has flour and water in it. What’s the difference?
18 minutes. From the moment that the water and flour touch, only 18 minutes can pass before the matzah is finished baking. Any longer, and the result is חמץ (chametz) – the matzah has leavened into bread (even if it still looks flat!). In Nitzanim, we made a list of foods in our lunch boxes and figured out which ones would qualify as חמץ (chametz). We mixed flour and water to see what would happen in 18 minutes.
Then we got to work with final preparations for Pesach! We finished our מצה (matzah) plate and our מרור (maror - bitter herbs) and מלח (melach - salt, for dipping parsley into salt water) bowls.
We cleaned חמץ (chametz) off our chairs.
And we finished sewing our (misubeen - reclining) pillows. Now we all have four items to use at our seders, one for each of the Four Questions!