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Sunday, February 23, 2014

Informational Text Reading with Graphic Organizers


Here's a great new free item for your science classroom:  
DNA Informational Text Reading with Graphic Organizers

I teach in a Common Core state, and in a school that is really pushing the implementation of the Common Core State Standards.  We have to show evidence of this implementation in our classroom.  I obviously have to do what is required of me by my admin, but at the same time, I do not want to lose valuable classroom teaching time and get behind on the vast amount of course content that I am also required to teach.

I recently developed this lesson for my students.  In our unit on DNA, RNA, and Protein Synthesis, I love to tell the history of Watson and Crick and their discovery of the structure of the DNA molecule.  In 1953, James Watson and Francis Crick rocked the scientific world with their discovery, and with the publication of their one-page paper in Science magazine describing the DNA molecule.  This one-page paper is a marvelous bit of history, and it is a fascinating read.  It is also a perfect piece of informational text that can be used to teach the Common Core State Standards.

The one-page article can be printed and used in your science classroom.  I developed a 4-page set of graphic organizers to go along with this article.  As students read the article they are required to complete the graphic organizers. You can have your students complete all four organizers (I usually do!) or each graphic organizer can be used alone.

You can, of course, use class time for this activity, but I usually assign this as a homework assignment.  I assign this at the beginning of my unit on DNA, and usually give a week to complete the assignment. The article and the graphic organizers provide great review on the topics I am teaching in class, as well as a lesson in the reading of informational text.  It's a win-win!  (Pssst...This is also a great activity to leave in your sub folder in the event of your unexpected absence from school!)

Here is a look at each of the graphic organizers:




(They look best if printed in color, but print perfectly fine in grayscale.)

This is a free download, and will always remain a free download.  Enjoy!

Related products include:




Saturday, February 15, 2014

Chemistry Lab: Composition of a Hydrate


This is the first time in about 7 years that I have taught a chemistry class.  My usual teaching assignment is a full day of AP Biology. My school made the transition this year from a 5 period day to a 7 period day, thus the need to assign teachers additional classes to teach.  So this year I am doing chemistry labs that I have not done for some time..... and I am being reminded how much I love them! I love the mathematical and analytical nature of chemistry labs and the need for exact and precise laboratory procedures.

Lately, I have been teaching how to write chemical formulas and the naming of compounds.  So this past week we did a lab called "Composition of Hydrates."  Hydrates are compounds that have some number of water molecules attached to them.  The premise of the lab is simple:  A known mass of a hydrate is heated to release the water of hydration.  The mass of the resulting anhydrous salt is determined.  The difference in the mass of the hydrate and the mass of the anhydrous salt can be used to determine the formula of the compound.

In our lab, we used copper (II) sulfate pentahydrate. A fine crystal is needed for the lab.  Since we only had the medium crystal in stock, my students used a mortar and pestle to grind the crystals into a finer powder.

The hydrate is heated over a Bunsen burner in an evaporating dish to remove the water of hydration.  But first the empty evaporating dish must be heated to remove all water, allowed to cool briefly, and the mass of the empty dish determined.

Heating the hydrate to remove the water of hydration.

The anhydrous salt.
The difference in the "before mass" and the "after mass" is used to determine the mass of water lost.  Students are given directions in how to use this information to determine that the compound used was copper (II) sulfate pentahydrate.  I love the simplicity of this lab and the fact that my students clearly understood how to use this data to determine the formula of the compound.  All in all, a great day!

Click picture to view this product in my TpT store.

Saturday, February 8, 2014

Snow in the South....How Fun!!



We (my family and I) had the best time playing in our 3/4 inch of snow this morning!!  This is the most snow we have had in years.  Our little guy is 12 inches tall, and it took every bit of snow on our deck to build him.  This is so exciting for those of us in the deep south!


Tuesday, February 4, 2014

How much Vitamin C is in your fruit juice?



Lab: Determining the Amount of Vitamin C in Fruit Juices

I  have been doing this lab every year for a long, long time.  I always enjoy it, and so do my students. I often do this lab with my biology students when teaching about nutrition and digestion, but my favorite use of this lab is with my chemistry classes.  This lab is perfect to introduce the idea of titrations, equivalents, and as a review of dimensional analysis.

In this experiment the student will use a lab procedure known as a titration to determine the amount of Vitamin C found in a 6 ounce serving of various fruit juices.  I most often use orange juice, pineapple juice, and apple juice. 

A titration is the controlled addition and measurement of the amount of a solution of known concentration required to react completely with a measured amount of a solution of unknown concentration.  Titration provides a means of determining the chemically equivalent amounts of two substances.  

The materials list is short and consists of items found in almost all labs..... no fancy equipment required!  You will need:  Spot plate, Thin stemmed or microtip Beral pipets  (or medicine droppers),  White paper for background, Ascorbic acid standard solution,  Apple juice,  Orange juice,  Pineapple juice, Starch solution,  Iodine solution and Plastic Toothpick (stirrer).

In order to determine the amount of Vitamin C in the fruit juice, the student must first do a titration using a vitamin C (ascorbic acid) solution of known concentration.  An iodine/starch complex is used so that a color change can be detected.  The number of drops of iodine added will be used to determine the amount of Vitamin C present in the juice.  

When ascorbic acid (Vitamin C) comes into contact with iodine, it is oxidized to form dehydroascorbic acid.  When Vitamin C and iodine are in solution together, they will form iodide.  As iodine is added during the titration, iodide will continue to be formed until there is no more Vitamin C left in the solution.  At this point, iodine becomes present in the solution and the starch turns a blue-black color.  The starch is used as an indicator because it turns black in the presence of iodine, but not for iodide.  The amount of iodine that is added during the titration can be used to indicate the amount of Vitamin C present in the fruit juice.

Set up for the lab is quick and easy, and does not take a lot of advance preparation.  


This lab is available in my TpT store and can be viewed here:  Determining the Amount of Vitamin C in Fruit Juices.