2) features of the ocean floor; 3) the concept of sea-floor spreading; and. 4) the nature of the Earth's magnetic field and the fact that it has reversed its polarity many times in the past. The Earth's layers â The Earth is a layered planet consisting of crust, mantle and core (Fig. 1).
Run your sprinklers for 15 minutes. Use a ruler to measure the depth of water in each can. Add all the numbers, and then divide by the number of cans to find the average output. This average number is your sprinkler number. It is the average amount of water your sprinklers apply in 15 minutes.
The correct way to determine this is to set out coffee cans or cups in the lawn and see how long it takes to fill the containers with 3/4 inch to 1 inch of water. Then set the sprinklers in that zone to run for that length of time. You can generally set the sprinkler times in the following way.