What do your students know about the food of the gods, chocolate? Do they know it is extracted from a plant? Do they know where the plant occurs naturally, how it is cultivated, or processed? Do they realize the scope of the chocolate industry worldwide? What news stories relating chocolate to health are valid? Why should students care?

As Valentine’s Day approaches, let chocolate serve as a sure-fire hook connecting to a number of science topics and lessons. Studying ecology? Why not research the ecology of Theobroma cacao? Studying physical and chemical change? Melting chocolate and baking brownies couldn’t be better examples!

How about a science and society mini-unit focused on the chocolate industry — who it employs, how many, where, doing what, producing what products? Interested in investigating how human activities impact the environment? The chocolate industry can be the focus.

Doing a health and nutrition unit? What is chocolate composed of? What nutrients are in chocolate? Does chocolate cause acne? Obesity? Heart disease? Hyperactivity?

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

Physical Appearance and Anatomy of Theobroma cacao

Ask students where chocolate comes from. This may stump some, while others may know it comes from a plant. Can they imagine what the plant looks like? A tree? How big? What do the leaves look like? The fruit? A series of progressively deductive photos is found at http://www.delange.org/Cocao/Cocao.htm. The page starts with photos of entire trees and funnels down to the fruit and seeds. Students can get a good concept of the physical appearance of the plant. Other image sources are the U.S. Department of Agriculture (http://plants.usda.gov/java/profile?symbol=THCA) and the U.S. Geological Survey (http://images.nbii.gov/details.php?id=65317&cat=Fruit%20Trees).

If you have had some discussions of adaptations as related to biomes, have students infer the biome in which this tree occurs based on the apparent adaptations of its leaves, tree size, habit and/or fruit size. Can students infer the methods of pollination from this photo: http://www.botany.org/plantimages/ImageData.asp?IDN=07-006h&IS=700?

Fact Sheets

The first fact sheet was published by the Australian government and is very scientific, describing the taxonomy and distribution of the cacao tree. The second fact sheet is aimed at consumers. It describes what antioxidants and flavinols are and their health benefits.

http://www.nt.gov.au/d/Content/File/p/Fruit/FF3_cocoa.pdf

http://www.aging.state.pa.us/aging/lib/aging/2008_NC_Cocoa_Fact_Sheet.pdf

How Is Chocolate Processed?

This page from the Hershey Company gives both a print and a video version of the processing of chocolate. The video starts with images of T. cacao being harvested and then moves to the factory at Hershey, Pennsylvania. The following lesson from the Field Museum appears to be a good match for the video: http://www.fieldmuseum.org/CHOCOLATE/education_pdf/cc_lesson5.pdf

Exploratorium provides images and the history of chocolate, spanning from the Amazon and prehistoric American tribes who apparently ”invented” chocolate all the way to current scientific findings related to the health benefits of chocolate.

You can purchase raw or roasted beans and nibs (broken pieces of seed) from http://livesuperfoods.com/cacao.html to show students various stages of the chocolate-making process.

Research Projects

This press release from the U.S. Department of Agriculture identifies some fungal diseases that infect Theobroma cacao and explains why sequencing the tree’s genome will help in preventing infections. In addition, there are links to three related stories.

Miscellanea

Does chocolate cause acne? Every teenager is interested in this question and will be no doubt pleased when they read this short article from Indiana University School of Medicine: http://soundmedicine.iu.edu/archive/2002/mystery/acneChocolate.html

According to the Cleveland Clinic, chocolate may be helpful for those with heart disease: http://my.clevelandclinic.org/heart/prevention/nutrition/chocolate.aspx

Here’s an additional resource from the National Science Digital Library Middle School Portal: Chocolate Exhibition.

We Need Your Help

We want and need your ideas, suggestions, and observations. What would you like to know more about? What questions have your students asked? Do you have a favorite activity that you would like to share? We invite you to share with us and other readers by posting your comments. Please check back each week for our newest post or download the RSS feed for this blog. You can also request email notification when new content is posted (see right navigation bar).

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