You are going to design a clock to represent the different geologic eons throughout Earth's history. Here are the steps you need to take to complete your geologic time scale clock: Research how long each eon lasted. You also might want to include the three eras of the most recent eon.

Knowing that each hour of the clock is about 375 million years, determine how many hours each eon takes up on our 12-hour clock. For example, if an eon took 750 million years, that would take up two hours of the clock.

Within each eon, identify major events and the types of life that dominated the earth during that time.

How you design your clock is up to you. You can use a computer program to design your Clock of Eons or you can go old school and use poster board and markers. Let your imagination soar and create a Clock of Eons that will surely impress! Upload your clock in the box below.

You are still fascinated by the process of inkjet printing, as described in the opening storyline for this chapter. you convince your father to take you to his manufacturing facility to see the machines that print expiration dates on eggs. you strike up a conversation with the technician operating the machine. he tells you that the ink drops are created using a piezoelectric crystal, acoustic waves, and the plateau-rayleigh instability, which creates uniform drops of mass m = 1.25 ✕ 10−8 g. while you don't understand the fancy words, you do recognize mass! the technician also tells you that the drops are charged to a controllable value of q and then projected vertically downward between parallel deflecting plates at a constant terminal speed of 20.0 m/s. the plates are ℓ = 2.15 cm long and have a uniform electric field of magnitude e = 6.40 ✕ 104 n/c between them. noting your interest in the process, the technician asks you, "if the position on the egg at which the drop is to be deposited requires that its deflection at the bottom end of the plates be 0.17 mm, what is the required charge on the drop (in c)? " you quickly get to work to find the answer. (neglect the force of gravity.)