Fall Science for Children - Pomegranates

I considered entitling this post, "How to Throw Together a Unit Study Before Breakfast", as this particular chain of experiments came about after the children talked me into buying a couple of pomegranates, and a quick Internet search informed me, that November is National Pomegranate Month.  But, I decided instead, for the sake of brevity, rather than to tell you about funny coincidences, and mornings with extra minutes, and too much coffee, I'd just present an outline of a lesson plan - as if I'd had plan all along, and actually knew what I was doing. 

As it turns out pomegranates make a great centerpiece for a science focused unit study, with plenty of jump off points into geography, linguistics, history and literature along the way.

Materials needed:

• 2 or more pomegranates, depending on the number of children participating
• a large bowl, preferably glass, filled with water
• a Ziploc-type bag
• a rolling pin
• scissors
• one paper cup per student
• planting soil, enough to fill each cup
• a large package of clear plastic cups
• items for testing pH such as lemon juice, vinegar, baking soda, milk, etc.
• a produce scale
• measuring spoons and cups
• paper and pens for recording information
• coffee filters (optional) for making pH indicator strips
• a bag of fresh cranberries (optional) for comparative observation
• a number of clean spoons or straws for stirring
• paper towels

Book Suggestions:

• Pomegranates a Delicious Fruit by Veda Boyd Jones - an easy reader, good for younger children, but fact filled enough to be of interest to older students.  Contains a useful glossary of pomegranate related vocabulary.
• Any version of the Greek myth of Hades and Persephone.  We chose Demeter and Persephone, A Tale of Love by Megan Musgrove from Publication International's Treasury of Best-Love Children's Stories.  The myth explains how Hades, the god of the underworld, used a pomegranate to trick and trap Persephone, the daughter of Demeter and Zeus, into spending six months out of every year in the underworld with him.  It works both as a literature tie-in and as an additional science starter for an investigation into the science behind the seasons.

Additional Media:

• Good Eats Season 10, Episode 14 "Fruit 10 From Outer Space" (can be purchased for instant view from Amazon).  While the pomegranate episode is informative, entertaining, and rated TV-G, I would suggest previewing it if you plan on showing it to younger children.  There is an alcohol reference/recipe, and Mr. Brown's humor can tend toward the morbid and somewhat bizarre on occasion.

Target Age: 

Early elementary - high school, depending on the depth and scope of the research and discussion. Pomegranate lessons work especially well for mixed aged groups with plenty of information for older students, and lots of hands on fun for younger children.

Lesson Plan:

• Watch the Good Eats pomegranate episode.
• Weigh the pomegranates, before peeling them.  Then, weigh the arils/seeds, once they have been separated, zeroing out the weight of whatever container you put them in, to determine what percent of the the pomegranates' weight is from the "seeds".

• 

• Read about Hades and Persephone (mentioned in the Good Eats episode), while peeling the pomegranates, using the underwater method from the episode (also mentioned by Veda Boyd Jones). If you are working with a mixed group of ages, have an older child read the myth while younger children peel the pomegranate.

• This is a good opportunity to compare pomegranates to cranberries.  Cranberries (filled with air) float in water, while pomegranate arils (filled with sugary juice) sink.

• Plant some of the pomegranate seeds in dirt filled paper cups, as suggested in Jones' book.  This is also a great time to compare the seeds of the pomegranate to the tiny cranberry seeds (if you cut one open to look at the air pockets inside, you will be able to see the seeds as well).

• Place some of the pomegranate arils into a Ziploc bag, and roll a rolling pin over the top to juice them.  Snip a corner off the bag to allow the juice to pour out.  (This is the method suggested by Veda Boyd Jones.  Alton Brown suggests several additional methods.)

• Explain that anthocyanin is a pigment often responsible for the red color we see in things like
  
  cranberries, fall leaves, and flowers such as poinsettias.  
• Children familiar with anthocyanin might remember that it can be used as a pH indicator.  You can dip a coffee filter into the juice, and then cut it into strips once it is dry, or just mix solids or liquids directly into cups of the juice.
• Allow opportunity for children to test a number of household solutions such as milk, lemon juice, baking soda, soap, and so on with small amounts of the juice.  It will turn pink (not very dramatically because the juice begins as a red) when mixed with an acidic liquid, and dark purple (with bubbles, because the juice is also acidic to begin with) when mixed with a base.

• Once children have tested several liquids with the juice, have the arrange their cups (labeled with a sharpie) in order, from darkest to lightest.  Cranberry juice, made by steeping fresh cranberries in boiling water, can also be used as a pH indicator for comparison.

• Instruct children ahead of time not to taste the juice from any of their cups.  We used all edible ingredients, but even so, many would not have been pleasant tasting.  Be sure though to set aside some of the seeds, and juice for sampling, or for an experiment that can be tasted.

It's great to be a homeschooler.