Why do toasted rice crispies SNAP, CRACKLE and POP?
"When Kellogg's* Rice Krispies are toasted the cooked and dried rice "berries" expand their size (puff) to many times their normal size. Since the weight of the rice berry and its material mass remains nearly the same, the rice material is stretched to form very thin walls of the Rice Krispies structure. This is much like a very thin glass crystal. When subjected to a change in heat, a severe "stress" is set up and the thin wall fractures - creating a Snap, Crackle and Pop!
This happens in the cereal bowl when cold milk (i.e. heat stress) is poured in the Rice Krispies and presto SNAP! CRACKLE! POP! The sounds are made by the uneven absorption of milk by the cereal bubbles." (http://www.kelloggs.ca/whoweare/scp.htm)
Pour your child a bowl of crisp rice cereal and let her listen to the little rice "berries" after you pour a little cold milk on them. Observe how the toasted rice "crystal" cavities fill with milk.
Now for the experimenting...Set up a few bowls of dry cereal and a few cups of different liquids. Let your child pour the different liquids onto the dry bowls of toasted rice.
Do the rice "berries" make the same amount of sound when you pour a different type of liquid on them?
Try warm water, cold water, soda, warm milk and cold milk. Talk about your observations with your child.
Whip up a batch of "Rice Krispie Treats":
-Melt 1/4 cup butter
-Add 10oz marshmallows and mix around in the butter. Put back in microwave for about a minute so the marshmallows are melty
-Stir together to help melt the marshmallows down.
-Add 8 cups of toasted rice cereal and stir mixture all together until rice cereal is mixed in well.
-Pour mixture onto a sheet of plastic wrap. Shape the mixture into a ghost form...like a hay stack.
-Sit the mound onto another sheet of plastic wrap and smoosh the bottom of the mixture to flatten the bottom.
-Refrigerate to allow mixture to harden.
-Melt white chocolate chips in microwave. Remove chocolate and stir till smooth. Use a spatula to smooth chocolate over the toasted rice/marshmallow mounds.
-Refrigerate till chocolate hardens.
-Use a little melted white chocolate as "glue" to secure two black chocolate chips onto the ghosts as eyes.