Student Science Assessment Prompt

The Science of Chocolate

Course:  Middle School Physical/Life Science

(Solubility Nutrition)

 

Introduction – Below you will find some information that will help you get started with a research project.  Read the information carefully and think of a related research question that you would like to investigate.  Your job will be to design and conduct an experimental research project to answer this question and write a report of your findings.  There are six parts to your report. 

 

  1. Research Question / Hypothesis – A statement of what question you will investigate and your “educated prediction” about what you will find out through an experiment.
  2. Literature Review – A description of what information you have found out about the research question through reading books, magazines, personal interviews or web sites.
  3. Experimental Procedure – A step-by-step, repeatable description of how you will conduct your experiment to answer your research questions.
  4. Results / Data – Tables that contain the data you collect.
  5. Analysis – Graphs or statistical calculations you have created to make your data more meaningful.
  6. Conclusions – A description of what you found out by doing your experiment.  Include whether your hypothesis was found to be correct or incorrect, and what new directions you would investigate next to improve your experiment or answer new questions that arise.

The six parts of your research paper and how your responses to them will be evaluated are described in more detail in the rubric that your teacher will share with you.

 

The Science of Chocolate


 


Basic Information for Literature Review-.  .  Hot chocolate has been a beverage for thousands of years.  The Mayan Indians of Central America discovered the delights of cocoa as long ago as 600 Ad.  During his conquest of Mexico the 16th century, Cortez found that the Aztecs used cocoa beans to prepare the royal drink, “chocolatl” which meant warm liquid.  But the Aztecs’ chocolate was very bitter, so the Spanish sweetened it with cane sugar.  They took chocolatl back to Spain, where the drink further enhanced with newly discovered spices, such as cinnamon and vanilla.  For breakfast, the Spanish elite drank their chocolate boiled in wine, heavily spiced and sweetened, and served in deep cups.

            Humans savor milk chocolate, but we also take it for granted, knowing little of the centuries-long struggle to combine these two flavors.  Few realize that milk and chocolate are natural enemies:  milk is 89% water, chocolate 80% fat (cocoa butter).  And just as oil and water don’t mix, so it is with milk and chocolate.  Milk also contains a lot of butter fat, which has a tendency to turn chocolate rancid.  And its molecular structure doesn’t match well with chocolate’s resulting in a product that tends to be lumpy instead of creamy smooth.  For these reasons, milk chocolate is a surprisingly recent invention.  For centuries, it eluded the efforts of monks, doctors, chemists and chefs.  By the time milk chocolate was mastered, inventors had already unlocked the secrets of the submarine (1775), the electric streetcar (1834), the telegraph (1837), and the camera (1839). 

For most of human history what was called chocolate was actually a beverage made from coarsely ground cocoa beans and spices—a bitter heavy precursor to today’s hot cocoa.  Although no one knows how humans struck upon the process of making the drink, archaeological evidence reveals that the ancient peoples of Mesoamerica were enjoying it as early as 1000 B.C.  By the time of Christ, cacao tree cultivation had reached Aztec civilization in Mexico, where chocolate was believed to be divinely inspired—a gift from the god Quetzalcoatl, who brought the seeds of the cocoa tree from the Garden of Life and gave them to Man.  When the famous Swedish botanist, Carolus Linnaeus, formally named the cacao tree, he paid homage to the divine roots, calling it Theobroma cacao, meaning “foods of the gods.”

By 1828, the first cocoa powder producing machine had been developed, which generated a less acidic, processed cocoa.  The new form of cocoa was easier to blend with warm milk or water.

Today, there are two types of warmed chocolate drinks.  Hot cocoa is the less fattening variety, made with milk and real chocolate.  Hot chocolate is a velvety textured drink, made with various spices or liqueurs.  Students might want to conduct taste tests to determine people’s favorite. 

Nutritional comparisons could lead to a study of hot chocolate mix drinks.   Chocolate is increasingly being recognized as an excellent source of minerals that are hard to find elsewhere.  Chocolate contains essential nutrients such as iron, copper, calcium and potassium, as well as vitamins A, B1, C, D, and E.  The cocoa bean is the richest source of magnesium in nature.  Magnesium deficiency is linked with heart disease, hypertension, diabetes and joint problems. 

 

 

Resources Related to Chocolate

HOT CHOCOLATE

Aztec emperor Montezuma drank 50 golden goblets of hot chocolate every day. It was thick, dyed red and flavored with chili peppers. (Is THAT why it’s called Hot Chocolate!)?

Dissolvability \Dis*solv`a*bil"i*ty\ (?), n. Capacity of being dissolved; solubility. --Richardson.
-- web1913

Solubility \Sol`u*bil"i*ty\ (?), n. [Cf. F. solubilité.] 1. The quality, condition, or degree of being soluble or solvable; as, the solubility of a salt; the solubility of a problem or intricate difficulty.  2. (Bot.) The tendency to separate readily into parts by spurious articulations, as the pods of tick trefoil.
-- web1913

Cocoa mix Also called instant cocoa, this mixture of cocoa powder, dry milk and sugar is combined with cold or boiling water to make a cold or hot, chocolate-flavored beverage.

Mexican chocolate:  Flavored with cinnamon, almonds and vanilla, this sweet chocolate is available in Mexican markets and some supermarkets.  Mexican chocolate has a much grainier texture than other chocolates.

Rediscover True Hot Chocolate

 - ... Rediscover True Hot Chocolate. There is a difference between hot cocoa and hot chocolate. ... Hot chocolate is made from chocolate bars melted into cream. ...
http://whatscookingamerica.net

 

Hot Chocolate -- A Mini Unit - Home Schooling Education - ... Hot Chocolate -- A Mini Unit by Kathryn Martinez Smell the aroma of hot chocolate? This is a great mini unit for a cold winters day. ...
http://www.easyfunschool.com/article1899.html

 

FamilyFun: Kids Food: Real Hot Chocolate - ... CHOCOLATY HOT CHOCOLATE Real Hot Chocolate from FamilyFun by Jim Gipe, Few people know the difference between hot cocoa and hot chocolate ...
http://familyfun.go.com

 

Chocolate – melting the myths (Chemistry of Chocolate)

Researchers have come up with several explanations as to why some of the stories are only cultural myths.  Science also presents some compelling theories in defense of chocolate.

http://www.chemsoc.org/chembytes/ezine/1997/chockie.htm

Chocolate hearts-Flavonoids seem to protect against heart disease, but which foods are the best sources, and how do they work? Chocolate may be one of the foods.

http://www.chemsoc.org/chembytes/ezine/images/2002/stevenson_apr02.htm

Not naughty, but nice-Increasing consumer demand for products that are low in calories has prompted the confectionery industry to find alternatives to tradition ingredients such as sugar and fat.

http://www.chemsoc.org/chembytes/ezine/1997/naughty.htm

Chocolate in bloom-Next time you reach out for your favorite chocolate bar you will probably pay little attention to its fat crystals. However, should you be unfortunate enough to peel back the wrapping to reveal a chocolate covered in a mouldy-looking white 'bloom', and then perhaps you might spare a thought for its crystal structure? The chocolate industry ploughs a lot of money into investigating chocolate crystals and bloom.

http://www.chemsoc.org/chembytes/ezine/2001/davies_jun01.htm

 

Instant powdered milk- Instant powdered milk has one major advantage over regular powdered milk - it mixes up much more easily.  Check this site for dissolving experiments for back ground.

http://waltonfeed.com/self/instantmilk.html

 

Recent research has indicated a possible antioxidant benefit in chocolate similar to that found in red wine

http://shop.store.yahoo.com/candy-crate/chocashealfo.html

 

Dissolvability \Dis*solv`a*bil"i*ty\ (?), n. Capacity of being dissolved; solubility. --Richardson.
-- web1913

 

Solubility \Sol`u*bil"i*ty\ (?), n. [Cf. F. solubilité.] 1. The quality, condition, or degree of being soluble or solvable; as, the solubility of a salt; the solubility of a problem or intricate difficulty.

2. (Bot.) The tendency to separate readily into parts by spurious articulations, as the pods of tick trefoil.
-- web1913

 

Instant Powdered Milk - ... The steam slightly dampens the milk Dissolvability Test - a teaspoon of regular milk on the left and a teaspoon of instant milk on the right... ...
http://waltonfeed.com/self/instantmilk.html

 

Choosing a Multivitamin - ... The have gone through a testing for dissolvability that mimics what happens in your body. Determine what is the best form for you to take. ...
http://cc.ucsf.edu/crc/nutrition_multivitamin

 

Solubility - ... solute dissolves into a solvent. It is almost easier to think of it as dissolvability of a substance. Note that solubility is ...
http://webeducator.net/lab37/assignments/chem

 

Quiz - ... C iced water. 13. The ability of a substance to dissolve is its: A solubility B dissolvability C melting ability. 14. A glass with ...
http://www.marsdenshs.qld.edu.au/subjects/sci

 

Unit Four Deep-Sea Sediment Coring Cindy Pilskaln Principal ... - ... Are some particles completely dissolved? 13. Have students analyze their results-How does dissolvability affect results? What is that similar to in real life? ...
http://www.marine.usf.edu/pjocean/packets/sp0

 

Solubility - Solubility Loretta Davis St. ... 2) To determine how to increase solubility. 3) To make a saturated solution using solvents at different temperatures. ...
http://www.iit.edu/~smile/ch9204.html

 

Experiments you can do at home: Solubility - Solubility. Can all substances dissolve in water? Materials. 2 Transparent cups; Water; Salt; Flour; Spoon. Procedure. Fill both cups with the same amount of water. ...
http://library.thinkquest.org/2690/exper/exp1

 

Nutrient Solubility - Nutrients and Solubility. Solubility Product Experiment.

http://wunmr.wustl.edu/EduDev/LabTutorials/Vi

 

Solubility - Solubility. Can all substances dissolve in water? Materials: 2 Transparent cups; Water; Salt; Flour; Spoon. Procedure: Fill both cups with the same amount of water. ...
http://www.reachoutmichigan.org/funexperiment
 

 

Standards, Benchmarks and Indicators

Standard 1 - Formulate research questions, conduct experimental investigations, analyze

 data, use appropriate technology, communicate results, defend conclusions, and propose further investigations

Standard 2-Analyze (quantitatively and qualitatively) the structures, properties, forms,

and patterns in matter and energy, predict changes and interactions, and evaluate

theories and structures using knowledge of chemistry and physics.

6.2.11.1 Observe changes to structure, properties, forms, interactions, and patterns in

matter and energy and design experiments using variables to test hypotheses.

 7.2.10.1 Identify and communicate properties of matter, including phases of matter,

boiling point, solubility, and density

Standard 6-Develop and understanding of personal and community health, population
 growth, natural resources, environmental quality, natural and human induced
 hazards, and science and technology in local, national and global settings.

NOTE: This standard should be integrated into physical science, life science, and earth science standards.

6.6.1        The student will make decisions based on scientific understanding of personal

Health

6.6.1.1  Identify individual nutrition, exercise, and rest needs based on science

6.6.1.2  Use a systemic approach to thinking critically about personal health risks and

Benefits.

Material Requirements

You will need to obtain the following:

Four different varieties of hot chocolate drinks (30 – 40 oz. Of each drink

 mix should be enough to accommodate 100 students)

Four beakers per student/group of four

One stir straw per student

Starting Points for Experimental Procedure

1.      Learning about brands from the labels.  Use the posted information from the labels of drinks A, B, C, D to fill out a chart to compare calories, total grams of fat, sodium, sugar, protein, % of vitamins A, B, and C, 5 of calcium and 5 of iron.  Use information from the chart to answer questions (for example which drink had the fewest calories, least fat, most iron) or make own questions to be answered.

2.      Measure the residue left after each drink sits/rests for a specific time.

3.      Have students take part in a taste and dissolving ability tests.

 

Cautions/Laboratory Safety

Warning:  The water only needs to be very warm for this experiment.  Extremely hot water could be dangerous in the classroom.  When drinking the hot chocolate for the taste test use caution.