Physical Change/Chemical Change/Edible DNA all in one post!

Exploring Creation with Biology

Module 5 – The Chemistry of Life

Sometimes it is hard to explain the difference between Physical Change and Chemical Change.  I don’t know why that is,but it is hard.

Physical Change –  A change that does not produce a new substance and is usually reversable.

Chemical Change – A change that makes a new substance and usually cannot be reversed.

Best way to get this idea across is with Play-Dough!  If I had time in the classroom I would have made homemade play-dough.  This would be a perfect example of Chemical Change.  Take salt, water, cream of tartar, food coloring etc… mix it, add heat and Wah-lah you have changed the ingredients into Play-Dough.  It cannot be undone.  Want a recipe for this?  You can find an Easy Homemade Play-dough recipe here.

It is sad that I did not have time to do that.  I handed each student one color of play dough.  I explained how the play-dough is made and that is a Chemical Change.  While they are playing around and sculpting, I explain Physical Change.

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I thought for sure they would just make balls or snakes, or a block.  You know, something not extraordinary.  Nope, the girls above made a petri dish and a pink butterfly.

Another student made a DNA strand, while another student (not even in my class, but likes to visit) made a snowman. LOL  My daughter below, got busy sculpting.

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She made a very cute elephant.  Is the elephant still play-dough?  Can it be squished back into the container or into another shape?  Why, yes it can!  That’s Physical Change, folks.

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There was only one class time for this module and it really needs to  be at least two.  Because of this I did not get into the Proteins, Enzymes, Carbohydrates, Acids and Bases, as much as I wanted.   With only 20 minutes left of the class, I gave the kids the fun project of making their own Edible DNA.  You can find the instructions at Teach Genetics.

Unfortunately, I didn’t have colored marshmallows.  We used gummy bears instead.  Marshmallows work a WHOLE LOT better.

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The kids started building, while also consuming copious amounts of Twizzlers and gummy bears.

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Yummy!  Edible DNA.  If you use marshmallows, the twist is easier and looks better too.  However; gummy bears taste better than colored marshmallows!

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After the photo below was taken, all Twizzlers and gummy bears were gone.  The girl second from the left ate seven Twizzlers and countless number of gummies.  The boy with the awesome spider shirt was so overloaded with sugar, he was bouncing off the walls in his English class.  That was his mom’s class.  She was thrilled.  That’s what I keep telling myself.

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Besides making the DNA, the students had to fill out a worksheet.  You can find my DNA worksheet here.  I will see if I can find a completed worksheet to post here, so you can see how they do it.

Have fun with play-dough and candy.


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