A baking sheet is an excellent surface to use for the experiment, though any smooth, surface will do fine, such as a wooden drawing board. Draw a grid with 10-cm spacing onto a paper taped to the baking sheet or wooden board, then cover with plastic wrap. In Class Using a protractor and plumb line, the baking sheet or board is propped up to an angle of 15 degrees for the procedure, then to an angle of 25 degrees for a repeat of the procedure. Students should pour the batter slowly and at a constant rate down the inclined board. The bucket should be held about 10 cm from the high end of the board.
Space is provided for sketches of the flow outline.
The part in the middle that is moving faster is called the channel interior. You may try sprinkling red confetti onto the flow to get a better view of the relative movement between the interior and levees. Presumably the batter volumes were the same for both slopes, but the flow areas could be determined and multiplied by the average depths as an exercise just to check. Use a ruler with a grid to slice into the flow at each 10 cm mark to get cross sections. Add more flour to the batter to see the behavior of a thick flow.