# Visualizations with Teaching Tips

We invited participants in the 2012 Teaching About Time workshop to share visualizations they use to teach about rates or time, along with a description of how they use the visualizations in their classes. Here they are.

### How Many Is a Million?

Roger Steinberg, in the Department of Natural Sciences at Del Mar College, has created a very large sheet of paper that contains one million dots to help students comprehend the immensity of a million. He writes,

"I first hand out individual copies of the 8 1/2 by 11 pieces of paper containing 5000 dots to each student, and ask them the significance. Students usually look for a pattern in the dots (which I may actually encourage), until I inform them that it is the number of dots on the page that is significant. I ask them to guess the number of dots on the pages. Usually, someone will eventually correctly guess (or calculate) 5000. Then I select a student to help me unfurl the large sheet of paper, and ask the class to guess (or quickly calculate) the number of dots on it. Most commonly the responses are 4.6 billion (age of the Earth) or 13.7 billion (age of the Universe). Students are always shocked when I reveal that the number is only 1 million."

### Visualizing the Precambrian

Roger Steinberg, in the Department of Natural Sciences at Del Mar College, has created a page-sized geologic time scale and an extended poster-sized geologic time scale, both drawn to scale, illustrating the immense span of time corresponding to the Precambrian. He writes,

"Students see the Phanerozoic portion of the extended time scale first. Then, I slowly unfurl my time scale addition to reveal the full Proterozoic, drawn at the same scale as the Phanerozoic. The Archean is unfurled next, followed by the Hadean. Figure 3 shows my entire extended geologic time scale, taped to my classroom wall.... Because the Phanerozoic portion of the Ward's time scale alone is 30 inches in length, my entire extended timescale is over 21 feet long."

### Geologic, Biologic, and Climatic Change Timelines

Pam Nelson, in the Physical Sciences Department at Glendale Community College, has developed a set of 11x14 diagrams that show the distribution of geologic, biologic and climatic change over Earth's history. She writes,

"These sheets are used as reference pages to assist students in correlating the various changes that occur over geologic time and how they relate to one another and/or make conditions right for another to occur.... Utilize this with any of the standard Historical Geology textbooks that separate the geology and biology of the each Era into two separate chapters to assist in student correlation."

### Life Time Line

Sarah Gerken, in the Biological Sciences Department at the University of Alaska, Anchorage, developed this slide showing an overview of major steps in the evolution of living organisms, with the relative amount of time since the origin of the planet. She writes,

"This is a version of a slide that I use in both my oceanography class and in my life on earth class, to try to get across major changes in organism evolution. Sometimes the teaching activity is to generate the timeline with the class, sometimes I use it more passively as in this case and show it while discussing the major steps."