Human Sense of Smell Is More Sensitive Than You Might Think

ScienceDaily has brought us yet another interesting article related to the National Science Education Standards Life Science Content Standard. My guess is that middle school teachers’ and students’ olfaction capabilities might be a bit superior to the general public’s, given my personal experience in teaching middle school! Nonetheless, scientists from Northwestern University’s School of Medicine report that imperceptible levels of scents affect our judgment in unconscious ways.

The article, Subliminal Smells Bias Perception About A Person’s Likeability, does not explicate the researchers’ questions or hypothesis, but inference indicates their questions were: What concentration levels of scents can people consciously detect? How does scent affect human judgment of the likeability of other humans?

Three scents were used at several levels of concentration, from imperceptible to definitely perceptible. The scents were: “lemon (good), sweat (bad) and ethereal (neutral). . . . Study participants were informed that an odor would be present in 75 percent of the trials.” After participants sniffed a sample, they were shown a photo of a human face with a neutral expression and were asked to rate the person’s likeability along a six-point scale. Though no details are given on how the data was analyzed, the lead author is quoted as saying,

The study suggests that people conscious of the barely noticeable scents were able to discount that sensory information and just evaluate the faces. It only was when smell sneaked in without being noticed that judgments about likeability were biased.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

Do your students participate in a Science Day competition or activity? Then you know how hard it can be to help students find a topic they can relate to and apply the methods of science. Sharing this article with your students and accompanying it with a discussion of the methods of science used here might just be the perfect bridge to help your students find an accessible topic. Since particular sample sizes and data analysis methods are not described in the article, you and your students could brainstorm a variety of possible approaches.

You could follow up by going through your local library’s electronic periodical data base to find the researchers’ original report in the December 2007 issue of Psychological Science, “Subliminal Smells Can Guide Social Preferences” by Wen Li, Isabel Moallem, Ken A. Paller, and Jay A Gottfried, and sharing with your students the methods these researchers did use. A discussion of the pros and cons of their methods as compared to those brainstormed by your students could round out your lesson.

The ScienceDaily article can also be used as an introduction to a unit on the senses (i.e., structure and function in living things) or on regulation and behavior, both topics within the NSES Life Science Standard. After sharing the article with students, ask: From an adaptive perspective, what value might there be in this phenomenon of imperceptible levels of scent causing unconscious behavior? Are humans the only organism likely to display this trait? How do you know?

Here are some additional resources that are part of the Middle School Portal 2 collection to facilitate your instruction regarding structure and function in living things, olfaction, methods of science, and regulation and behavior: Structure and Function in Living Systems; Enose Is Enose Is Enose; Discovery, Chance and the Scientific Method; Regulation and Behavior.

We Want Your Feedback

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? We invite you to share with us and other readers by posting your comments. Please check back often for our newest posts or download the RSS feed for this blog. Let us know what you think and tell us how we can serve you better. We appreciate your feedback on all of our Middle School Portal 2 publications. You can also email us at

This post was originally written by Mary LeFever and published December 13, 2007 in the Connecting News to the National Science Education Standards blog. The post was updated 4/23/12 by Jessica Fries-Gaither.

Consumer Safety: Antifreeze in Toothpaste

We’re ever thankful when our students come to school with freshly brushed teeth, but could there be a circumstance under which you would suggest your students not use toothpaste? In May of 2007, BBC News reported that the Chinese government was investigating charges that toothpaste containing diethylene glycol, also known as antifreeze, had been exported to other countries.

In the following months the New York Times, Fox News, and others identified the tainted brands of toothpaste and locations where they were sold. Some brands were found to contain the compound even though it wasn’t listed as an ingredient. Unfortunately for China, the tainted toothpaste adds to a growing list of product-safety breaches, including a similar incident with cough syrup in 2006 and, more recently, the use of lead-based paints in children’s toys.

In the United States, the Consumer Product Safety Commission provides information and issues safety alerts on consumer products. In the wake of the incidents involving lead-based paint on toys, the Commission reached an agreement with China, requiring imported toys and some other products to meet U.S. safety standards. In addition, the U.S. Food and Drug Administration got involved with the tainted toothpaste issue, developing a web page devoted to the problem.

To what extent should individuals rely solely on government agencies to look out for their personal safety? How much scientific literacy do consumers need to be able to read labels and make informed decisions regarding their own health and safety? These questions are addressed in an October 1, 2007, article in the New York Times, The Everyman Who Exposed Tainted Toothpaste. This article tells the story of how one person, Eduardo Arias, brought the issue of tainted toothpaste to the attention of the world.

Arias is a Panamanian government employee responsible for reviewing environmental reports, but that’s not the reason he recognized the compound in the list of toothpaste ingredients as toxic. Rather, he was made aware of diethylene glycol’s toxic effects when, in 2006, almost 100 people died after consuming tainted cough syrup from China, another story reported by the New York Times. Bringing the danger of the tainted toothpaste to the attention of the proper authorities required Arias to cut through the government bureaucracy at three levels and cost him a considerable amount of personal time. His story exemplifies the human side of safety in society and personalizes an issue that could easily be perceived as something the government is solely responsible for. His story should inspire others to do the right thing, despite the probable inconvenience doing so brings.

How to Turn This News Event into an Inquiry-Based, Standards-Related Science Lesson

What’s so dangerous about diethylene glycol? Why would it be used in toothpaste? How can average citizens be proactive in maintaining their own and others’ safety when it comes to consumer products? These are questions for inquiry that align with several of the National Science Education Standards in the areas of Science as Inquiry, Physical Science, and Science in Personal and Social Perspectives.

The intention here is not to scare middle school students, but to show them there are mechanisms in place to maintain our safety, and these mechanisms require active, informed, scientifically literate citizens. We all have a responsibility to stay informed. Teachers have a responsibility to assist students in learning where and how to access the needed information as well as how to evaluate it for its authenticity, validity, and usefulness. This approach provides opportunities to integrate skills and knowledge in language arts, social studies, and science.

We Want Your Feedback

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? We invite you to share with us and other readers by posting your comments. Please check back often for our newest posts or download the RSS feed for this blog. Let us know what you think and tell us how we can serve you better. We appreciate your feedback on all of our Middle School Portal 2 publications. You can also email us at

This post was originally written by Mary LeFever and published October 3, 2007 in the Connecting News to the National Science Education Standards blog. The post was updated 4/23/12 by Jessica Fries-Gaither.


Celebrate Women’s History Month with STEM Stories

The STEM Stories website features a growing collection of digital resources that highlight the lives and work of individuals involved in STEM fields (mainly women). It combines compelling personal stories and multimedia to interest intermediate and middle school students in STEM subjects and careers.

From the In the Spotlight menu, you’ll meet 10 present-day women who are featured in depth, with interviews, photo albums and more.  They include dolphin communication researcher Diana Reiss, atmospheric chemist Susan Solomon, biologist and astronaut Millie Hughes-Fulford, and robotics engineer Heather Knight. (Heather helped work on the Rube Goldberg machine sequence for the OK-Go music video This Too Shall Pass).  On the Clips tab, the database includes short videos that introduce individuals working in varied STEM careers.  The Profiles tab lets you search biographies about women working in STEM fields throughout history.  Some include photo albums, such as Mary Pennington, Rachel Carson, and Virginia Apgar. (Tip:  double-click on images to see a larger view).

The project team, headed by Lois McLean and Rick Tessman (McLean Media) created STEM Stories with girls in mind, drawing on design ideas from an after-school club for at-risk middle and high school girls. In a 2010 pilot, more than 200 students (Grades 4–7) in Nevada County, California, used the site in classroom activities. In one school, fourth- and seventh-grade students worked in pairs to create pop-up books based on featured individuals. Survey results found no major differences between the responses of boys and girls. In fact, teachers reported that students did not even comment on or question the site’s emphasis on women. And, although the website focuses on personal stories, most students also reported learning something new about science and engineering.

STEM Stories was funded through a grant from the NSF’s Research on Gender in Science in Engineering Program (#HRD-0734004). New content is being added every month, including more current and historical photos, profiles, videos, and interactives.

To introduce your students to the STEM Stories site, try these activities:

STEM Stories Treasure Hunt

STEM Stories Crossword Puzzle

STEM Stories Lesson Ideas

We Want Your Feedback
We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? We invite you to share with us and other readers by posting your comments. Please check back often for our newest posts or download the RSS feed for this blog. Let us know what you think and tell us how we can serve you better. We appreciate your feedback on all of our Middle School Portal 2 publications. You can also email us at Post updated 4/19/2012.

The Science of Sports II

Looking for “sporty” ways to teach your students about science? Here are some resources from the Middle School Portal 2 Digital Library. You can do your own searches at MSP2 Collection of Resources.

Science of NFL Football
In America, the autumn season means two things–back to school and back to football. To celebrate both events, NBC News’ educational arm, NBC Learn, teamed up with the National Science Foundation (NSF) and the National Football League (NFL) to release the “Science of NFL Football”–an informative 10-part video series that explores the science behind America’s most beloved sport. Made especially for students and teachers as they head back to the classroom, these videos are aligned to lesson plans and national state education standards. Lessons plans for middle school students that accompany each video can be found at

For each segment in the series, an NSF-supported scientist explains the selected scientific principle, while NFL athletes describe how these principles apply to their respective positions. Series scientists supported by NSF are: University of Florida aerospace engineer Tony Schmitz, Clemson University mechanical engineer John Ziegert, University of Maryland physicist Sylvester “Jim” Gates and Bryn Mawr College mathematician Rhonda Hughes. Also participating in the series are two scientists from the University of Connecticut, kinesiologist Douglas Casa and nutritionist Nancy Rodriguez. Current players and retirees who participated in the video series include:

Former NFL Players:
* Orlando Pace, Tackle
* Hardy Nickerson, Linebacker
* Antonio Freeman, Wide Receiver
* Joey Harrington, Quarterback
* Marshall Faulk, Running Back
* Craig Hentrich, Punter
* Morten Andersen, Place Kicker
* Ryan Kuehl, Long Snapper

Current NFL Players:
* Hines Ward, Wide Receiver, Pittsburgh Steelers
* Antwaan Randle El, Wide Receiver, Pittsburgh Steelers
* Scott Paxson, Nose Tackle, Pittsburgh Steelers
* Patrick Cobbs, Running Back, Miami Dolphins
* Yeremiah Bell, Safety, Miami Dolphins
* Jake Long, Tackle, Miami Dolphins
* Dan Carpenter, Place Kicker, Miami Dolphins
* Lousaka Polite, Running Back, Miami Dolphins

The Science of Speed
The Science of Speed, produced for the National Science Foundation (NSF) and written and hosted by Diandra Leslie-Pelecky, explains the scientific principles that are so essential to the NASCAR experience. Viewers learn how science makes cars powerful, agile, fast and safe – and how these same principles affect their own cars.

Science of the Olympic Winter Games
NBC Learn, the educational arm of NBC News, teamed up with the National Science Foundation (NSF) to produce Science of the Olympic Winter Games, a 16-part video series that explores the science behind individual Olympic events, including Downhill and Aerial Skiing, Speed Skating and Figure Skating, Curling and Hockey, and Ski Jumping, Bobsledding and Snowboarding. Each video is complemented with lesson plans which include fun classroom activities. The lesson plans were written by teachers at Academic Business Consultants for grades 6-9 and are aligned with California State Standards.

Exploratorium: Sports
The Exploratorium website provides creative educational materials for introductory physics students and teachers. Users can learn about the science behind a homerun, find out how the physics of balance helps enthusiasts surf the waves, and discover the physics behind many other popular sports. The site is equipped with interviews, enticing images, and enthralling descriptions. Visitors can find interesting articles covering sports topics such as fitness challenges for climbers and the way balls bounce.

Paintball: Chemistry Hits Its Mark
The first paintballs were fired by foresters and ranchers to mark trees and cattle. In the 1980s, someone got the idea that it would be more fun to fire paintballs at people than at trees and cows. Thus the sport of paintball was born. In this article from ChemMatters, learn how the one billion paintballs manufactured each year are a product of chemistry and engineering. You’ll need to scroll down a couple of pages to get to the Paintball article.

Golf Balls
Since the late 1800s, chemists have been called on to find ways to produce lighter, faster, and durable golf balls. This site traces the chemistry that has transformed the ball and promises to create a ball that will “soar like a cruise missile, hit the ground at a very shallow angle, and roll for up to 40 yards on hard ground.”

Extreme Adventure
Do you have what it takes to win the Ultimate Race? Find out with the Tryscience Extreme Challenge! Compete on seven courses in four sports- mountain biking, kayaking, rock climbing and snowboarding. You must train and apply the science behind the sport to beat the challenge time and earn each course medal.

Come to the Middle School Portal 2: Math and Science Pathways online network to discuss this and many other topics and connect with colleagues!

Snowflakes Grown in Labs Answer Questions About the Ones Falling from the Sky

If middle schoolers are cutting out paper snowflakes for holiday decorations and one student insists on cutting white triangles, that’s okay. The six-sided snowflake is most often depicted, but three-sided snowflakes are not uncommon. They’ve been observed in nature for hundreds of years. Noted snowflake photographer W.A. Bentley (celebrated in the Caldecott Medal Book Bentley’s Snowflakes) and other scientists recorded them.

Physicists Kenneth G. Libbrecht and H. M. Arnold have created triangular snowflakes, as well as hexagons, in their laboratory at the California Institute of Technology. They found that the majority of flakes grown in a vapor diffusion chamber were hexagons but more than they had estimated became triangles, leading them to look for the trigger that turns hexagons into triangular shapes.

According to the authors in their published report, ”We have been studying the detailed physics of snow crystals as a case study in crystal growth, with the hope that developing a comprehensive mechanistic model for this specific system will shed light on the more general problem of structure formation during solidification.”

A single small growth perturbation on the forming hexagon flake resulted in a distorted, or triangular, shape under certain aerodynamic conditions. The perturbation caused the falling flake to tilt up. The airflow around the crystal produced instability in the growth of the facets, creating the triangular shape. After the triangular shape is initially formed, the flake stays triangular during the rest of its fall.

Libbrecht and Arnold point out, “The growth of triangular snow crystals is another piece in the puzzle that describes the many interconnected mechanisms by which complex structures emerge spontaneously during solidification.”

For all those interested in snowflakes, Libbrecht created the web site, with photo galleries of real and synthetic flakes, frequently asked questions, tips on photographing crystals and preserving them, snow activities for all age groups, and more. Libbrecht used a specially designed snowflake photomicroscope to photograph flakes. In 2006, the U.S. Postal Service used his photos as a set of commemorative stamps.

More Snowflake Studies. At Purdue University, a Ph.D. candidate in chemistry, Travis Knepp, has been growing ice crystals in his lab, subjecting the crystals to temperatures ranging from 110 degrees Fahrenheit down to minus 50 degrees. A press release from the university reports that Knepp’s experiments are part of his study of ground-level ozone depletion in the Arctic.

Knepp explains, “Most people have probably heard of ozone depletion in the North and South Poles. This occurs in the stratosphere, about 15 miles up, What people don’t know is that we also see ozone levels decrease significantly at ground level.” The complex chemical reactions that take place on the snow crystal’s surface cause the release of chemicals that reduce ozone at ground level. “How fast these reactions occur is partially limited by the snow crystals’ surface area,” he said. His findings are published in the journal Atmospheric Chemistry and Physics.