Please Explain from WNYC New York Public Radio

Fertilizer is crucial for food--plants need it in order to grow and thrive. Harold Van Es, professor in the Department of Crop and Soil Sciences at Cornell University, explains what fertilizer is made of, why it's so important, and how to manage it.Let us know if you have a question! Leave it as a comment or call us at 212-433-9692.?

Grains have been a cornerstone of the human diet since the dawn of civilization. We'll find out about the wide variety of grains and the difference between whole, refined, and enriched grains.Abdullah A. Jaradat, USDA Department of Soil Management Research, and Maria Speck, author of Ancient Grains for Modern Meals, explain.

If you look at many packaged food, you're likely to find the words "natural flavors" and "artificial flavors" on the ingredients list. These terms seem ambiguous, but they explain why much of the foods Americans eat tastes the way it does. For today's Please Explain, explain Dr. Gary Reineccius, professor and head of the Flavor Research and Education Center in the Department of Food Science and Nutrition at the University of Minnesota, and Barb Stuckey, professional food developer and author of Taste: Surprising Stories and Science about Why Food Tastes Good, explain what natural and artificial flavors are, how they're made, and why they're used in everything from cough syrup to candy to French fries to frozen yogurt.

Baking can?seem?like magic, but it's not--it's chemistry! And understanding even a?little?about what is going on when you combine ingredients and add heat can make you a much more successful and satisfied baker.Shirley Corriher, author of BakeWise: The Hows and Whys of Successful Baking, and Chef Scott McMillan, a pastry art Instructor at the Institute of Culinary Education in New York City,?explain the particulars of baking--from different flours to measuring by weight to the differences between baking powder and baking soda.Let us know if you have a question about baking. Leave a comment!

This week's Please Explain is all about so-called superfoods--natural, whole foods that are superior sources of anti-oxidants and essential nutrients. Dr. Drew Ramsey, assistant clinical professor of psychiatry at Columbia University, and co-author of The Happiness Diet and the forthcoming Fifty Shades of Kale, explains which foods are healthiest--from nuts to fish to olive oil to grass-fed beef--for our bodies and our brains.

There's growing concern that endocrine disrupting chemicals have been linked to health problems in humans, and this month a report issued by the World Health Organization and the United Nations Environment Programme called these chemicals a "global threat" that should be addressed. Heather Patisaul, Associate Professor, Department of Biology, North Carolina State University, and Urvashi Rangan, director of the Consumer Safety and Sustainability Group at Consumer Reports, explain what endocrine disruptors--like BPA, phthalates, some pesticides and fire retardants--are, where they're found, and how they affect human development and health.

There's growing concern that endocrine disrupting chemicals have been linked to health problems in humans, and this month a report issued by the World Health Organization and the United Nations Environment Programme called these chemicals a "global threat" that should be addressed. Heather Patisaul, Associate Professor, Department of Biology, North Carolina State University, and Urvashi Rangan, director of the Consumer Safety and Sustainability Group at Consumer Reports, explain what endocrine disruptors--like BPA, phthalates, some pesticides and fire retardants--are, where they're found, and how they affect human development and health.

This week's Please Explain we'll find out what nurses do, how they're trained, and why there always seems to be a shortage. Dr. Bobbie Berkowitz, Dean of Columbia University School of Nursing, explains the art and science of nursing. She's joined by Ghislaine Chery, nurse at Jamaica Hospital and for the Visiting Nurse Service of New York.

This week's Please Explain we'll find out what nurses do, how they're trained, and why there always seems to be a shortage. Dr.Bobbie Berkowitz, Dean of Columbia University School of Nursing, explains the art and science of nursing. She's joined by Ghislaine Chery, nurse at Jamaica Hospital and for the Visiting Nurse Service of New York.

For this week's Please Explain, we'll find out how we process all the sounds we hear every day--from the hum of the heater to the wail of sirens to music to speech--and how it shapes our brains and behavior. Seth Horowitz, neuroscientist and assistant research scientists at Brown, explains how we hear, why songs get stuck in our heads, why certain sounds make us cringe while others are soothing, the ways we've learned to manipulate sound, and the difference between hearing and listening. He's the author of The Universal Sense: How Hearing Shapes the Mind.

For this week's Please Explain, we'll find out how we process all the sounds we hear every day--from the hum of the heater to the wail of sirens to music to speech--and how it shapes our brains and behavior. Seth Horowitz, neuroscientist and assistant research scientists at Brown, explains how we hear, why songs get stuck in our heads, why certain sounds make us cringe while others are soothing, the ways we've learned to manipulate sound, and the difference between hearing and listening. He's the author of The Universal Sense: How Hearing Shapes the Mind.

Some 45 million Americans belong to a gym or exercise on their own, hoping to improve their physical fitness and their health. Gretchen Reynolds, writer of the New York Times Phys Ed column and author of The First 20 Minutes, answers questions and debunks myths about exercise. She explains the latest research on the mental and physical benefits of exercise and tells how much and what kind of exercise is needed to stay fit, improve health, or lose weight.If you have a question about exercise, leave it as a comment! Or call during the show at 212-433-9692.

When you drop a letter in a mailbox, how exactly does it end up where it's supposed to go? We'll find out how the U.S. Postal Service works and why it's struggling for survival. Nancy A. Pope, curator from the National Postal Museum and organizer of Systems at Work, and Richard John, professor at Columbia University School of Journalism and author of Spreading the News: The American Postal System from Franklin to Morse.

Corey S. Powell, Editor at Large of Discover magazine, talks about the biggest stories in science last year--including the new Mars rover; the discovery of the Higgs boson; the Human Microbiome Project; climate change, storms, and melting polar ice; private space flight; self-driving cars; the comeback of measles, mumps, and whooping cough; and more! We've covered a number of the stories listed in Discover's top science stories of 2012:Please Explain: Fungal Meningitis and Compounding PharmaciesPlease Explain: Prosthetics (including mind-controlled prosthetics)Please Explain: The Higgs BosonPhysicist Lisa Randall on the Higgs boson discoveryPlease Explain: The Human Microbiome ProjectArsenic in Rice?

Today's Please Explain is all about helium and the helium shortage. We speak with Dr. Martin Stute, a noble gas geochemist at Barnard college and Lamont-Doherty Earth Observatory and with Dr. Joe Peterson a Bureau of Land Management Assistant Field Manager for Helium Resources in the BLM Amarillo, Texas Field Office.?