Earth’s Cycles in Action Diane Dakers. St. Catharines, ON: Crabtree, 2015. 48 pp., pbk., hc., pdf & html, $11.95 (pbk.), $23.49 (RLB.). ISBN 978-0-7787-0619-9 (pbk.), ISBN 978-0-7787-0640-3 (RLB.), ISBN 978-1-4271-7624-0 (pdf), ISBN 978-1-4271-7620-2 (html). Subject Headings: Earth sciences-Juvenile literature. Earth (Planet)-Juvenile literature. Grades 5-8 / Ages 10-13. Review by Barbara McMillan. **** /4
	Earth’s Water Cycle. (Earth’s Cycles in Action). Diane Dakers. St. Catharines, ON: Crabtree, 2015. 48 pp., pbk., hc., pdf & html, $11.95 (pbk.), $23.49 (RLB.). ISBN 978-0-7787-0625-0 (pbk.), ISBN 978-0-7787-0617-5 (RLB.), ISBN 978-1-4271-7627-1 (pdf), ISBN 978-1-4271-7623-3 (html). Subject Heading: Hydrologic cycle-Juvenile literature. Grades 5-8 / Ages 10-13. Review by Barbara McMillan. **** /4
	The Carbon Cycle. (Earth’s Cycles in Action). Diane Dakers. St. Catharines, ON: Crabtree, 2015. 48 pp., pbk., hc., pdf & html, $11.95 (pbk.), $23.49 (RLB.). ISBN 978-0-7787-0621-2 (pbk.), ISBN 978-0-7787-0672-4 (RLB.), ISBN 978-1-4271-7625-7 (pdf), ISBN 978-1-4271-7621-9 (html). Subject Heading: Carbon cycle (Biogeochemistry)-Juvenile literature. Grades 5-8 / Ages 10-13. Review by Barbara McMillan. **** /4
	The Nitrogen Cycle. (Earth’s Cycles in Action). Diane Dakers. St. Catharines, ON: Crabtree, 2015. 48 pp., pbk., hc., pdf & html, $11.95 (pbk.), $23.49 (RLB.). ISBN 978-0-7787-0623-6 (pbk.), ISBN 978-0-7787-0599-4 (RLB.), ISBN 978-1-4271-7626-4 (pdf), ISBN 978-1-4271-7622-6 (html). Subject Heading: Nitrogen cycle-Juvenile literature. Grades 5-8 / Ages 10-13. Review by Barbara McMillan. **** /4

excerpts:

The Moon’s gravity pulls everything on Earth toward it. The pull of the Moon’s gravity on mountains and other solid objects is relatively slight. Water moves more easily, however, so we see the Moon’s effect on the ocean as water levels rise and fall and the tide goes in and out. (From Earth’s Cycles.) All the water that has ever existed still exists today. For millions of years it has traveled through the various steps of the water cycle over and over again. In addition to moving water around the planet and changing its state from solid to liquid to gas, the water cycle also cleans the water. Today, though, natural processes aren’t enough. The water cycle can’t keep up with all the damage that humans are doing to the world’s water supply. (From Earth’s Water Cycle.) Animals cannot live without plants for two simple reasons. First of all, green plants produce oxygen, something most organisms need to survive. Whether they do it through lungs, gills, or their skin, nearly all animals take in oxygen, or O2. Another element plants supply is carbon, a necessity for all forms of life on Earth. Plants deliver carbon in the form of sugars, starches, or proteins. Each of these carbon compounds gives animals, including you, energy for growth, strength, and healthy bodies. Some of the best known carbon compounds are carbohydrates. (From The Carbon Cycle.) Many types of bacteria live in the soil. Bacteria are single-celled organisms, or life forms, so small that you need a microscope to see them. Some bacteria in the soil take nitrogen gas from the air and change it into compounds that help plants grow. These bacteria, and some bacteria in water, are the only organisms that use nitrogen gas directly from the air. Without these bacteria, no living thing would get the nitrogen it needs to exist. (From The Nitrogen Cycle.)

Cycles are ubiquitous on Earth, and this is a fact that Diane Dakers makes clear in her “Earth’s Cycles in Action” series for Crabtree Publishing Company. She suggests that many of these cycles occur “so regularly and constantly” that we seldom think about them. Within this group are the observable cycles that include the cycle of day and night, the cycle of the seasons, the phases of the moon, the water cycle, and weather cycles that result in warm/hot summers and cool/cold winters in Canada and other parts of the Northern Hemisphere. In addition to these cycles driven by the motions of Earth relative to the Sun and Moon, there are many more cycles occurring on Earth that can’t be seen with the naked eye. These sub-microscopic cycles involve the recycling of elements, the building blocks of every non-living and living thing on Earth. Since matter can’t be created or destroyed, it must recycle. Plants and animals and other organisms without the continuous cycling of elements like nitrogen, carbon, hydrogen, and oxygen would not survive. This is the first big idea that Dakers helps adolescent and teenaged readers to understand.

     The second big idea is that the cycling of natural elements from air to soil to animals, or from air to plants to animals, and back to the soil and the air is in perfect balance, or has been until the most recent one hundred years. The large and growing human population and the way we live on the planet is “harming the atmosphere”, “polluting water”, “disrupting the nitrogen cycle”, and “throwing the carbon cycle dangerously out of balance”. The consequences of these actions are a thinning of the ozone layer, unusual weather patterns, climate change, thermal pollution of Earth’s oceans, melting of the polar ice caps, algae blooms, acid rain, nitric oxide smog, water scarcity, contaminated drinking water, and water-related illnesses.

     Given this ominous state of the planet, Dakers’ third big idea is one of hope. She describes many of the projects scientists and engineers are working on to undo the harm that has been done to the atmosphere, soil, waterways, oceans and lakes. These include tidal power and other renewable energy sources, airplanes that run on solar power and trains that run on magnetic force, water purification systems that kill harmful bacteria and clean sewage and industrial wastewater, fog nets that capture water droplets, desalination of the ocean’s water, and the sequestering of CO2 underground. In Earth’s Water Cycle, The Carbon Cycle and The Nitrogen Cycle, Dakers also provides readers with well-considered lists of changes they can make to reduce their carbon footprint, to help the nitrogen cycle stay in balance, and to reduce the volume of water used each day.

     The 48 pages of each book in the “Earth’s Cycles in Action” series are divided into six or seven chapters. Each chapter contains at least one stock photograph or diagram per page and several types of text boxes that are carefully positioned around the main text. Some of these text boxes are used to describe what is pictured in each image, others present information that supplements the information in the text. Those that I appreciated most were the text boxes titled “Making Sense of Cycles”. They provided an opportunity for readers to slow down and think about the presented information in order to make sense of it, to process it more deeply, or to search for supporting evidence to respond to a question or statement using the information in the preceding pages of the text. As one example, in Earth’s Cycles Dakers writes, “Think of the way the Moon affects Earth. Now imagine Earth without its Moon. What kinds of things would change? How would life be different? In what way do you think things might not be affected at all? Use information from the book to explain your thinking.” These are beautiful thought problems that require readers to think like a scientist and to use what they know and understand to provide a valid, evidence-supported answer.

     In addition to the well-informed content and presentation, Dakers also includes two pages near the end of the book - just before the glossary, lists of relevant books and websites, and index - that she titles “Do It Yourself”. In The Water Cycle, The Nitrogen Cycle, and The Carbon Cycle, the suggested activity and challenge is the creation and investigation of a water cycle in plastic self-sealing bag, the impact of nitrogen fertilizer on plant growth, and the decomposition of plant material by microorganisms in soil, respectively. The activity suggested in Earth’s Cycles is an internet research project that has readers looking at the impact of the location (latitude) of eight North American communities on the length of the period of daylight on June 21st (summer solstice) and December 21st (winter solstice). The challenge goes beyond determining which community has the longest and shortest days and encourages readers to look for patterns in the data and, once identified, to make predictions about the length of daylight in locations south of the southern most community for which data was recorded. As with the “Making Sense of Cycles” text boxes, Dakers is inviting readers to carry out the experimental work and research of scientists. Given the information she has made available in the preceding pages, they will have the knowledge and understanding to meet the challenges she has established.

Highly Recommended.

Barbara McMillan is a teacher educator and a professor of science education in the Faculty of Education, the University of Manitoba.

To comment on this title or this review, send mail to cm@umanitoba.ca.

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