Thursday, September 13, 2018

Demonstrating a Chemical Change for Halloween

Halloween Chemistry

Halloween is a great time of year for chemical reactions.  We don't just want any chemical reaction.  We want ones that create excitement with the students and also impress the principal if they walk in.  It is important to make sure our Halloween chemistry also meets the standards.



Here are 5 must have chemistry experiments that will help create a memorable moment for students and meet the standards.

All these experiments focus on teaching the 5 signs of a chemical Change.

1.  Formation of a Gas
2.  Formation of a Precipitate
3.  Unexpected Color Change
4.  Temperature Change
5.  Energy Production

Effervescent Tablet Exploration
(Alka-Seltzer)
This reaction is perfect for teaching the formation of a gas.  Think of it like the classic vinegar and baking soda reaction in a tablet.  The tablet contains citric acid which represents the acid.  The tablet also contains sodium bicarbonate which represents the base.  When the tablet is placed in water carbon dioxide gas is produced.  To test that it is carbon dioxide gas I like to put a flame over the reaction.  The carbon dioxide gas will smother the flame.  If it was oxygen the flame would glow brighter.  I like to add some dish soap to make it bubbly too.  Click image to learn more things you can do with effervescent tablets.




http://kimberlyscottscience.blogspot.com/2015/10/13-days-of-halloween-alka-seltzer-fun.html
The candle will go out when placed over the container.  Click image to learn how.


Falling Precipitate
This is a great example of the formation of a precipitate in a chemical reaction.  Epsom Salt is hydrated magnesium sulfate.  Washing soda is sodium carbonate.  Sodium carbonate is used as a water softener in laundry detergent.  Both are easy to find.  When they are mixed together as solids nothing happens.  They need to be in an aqueous solution.  When the solutions are combined they are able to react to form the precipitate (solid) magnesium carbonate and sodium carbonate (still in solution).  The formation of the solid is an exciting surprise for students.   Learn more in the video.




Red Cabbage Juice Indicator
Red cabbage juice is an acid/base indicator.  This means it will change color in the presence of an acid or a base.  It will turn red/pink in the presence of an acid and green in a base.  The more acidic the pinker it is.  The more basic the more green.  Students have a great time testing the red cabbage juice in different substances.  Learn more by clicking on the picture.

http://kimberlyscottscience.blogspot.com/2016/10/13-days-of-halloween-color-changing.html

Elephant Toothpaste
This is the best Halloween reaction.  I like to erupt it in a pumpkin.  This is an exothermic reaction.  That means it gives off heat.  It also gives off oxygen.  The students will get to see the production of heat and the production of gas.  I have done this for class Halloween parties.  I also use it to teach the scientific method.  Try it with students by clicking the image below.


Glow Stick Science
I like glow sticks because many parents have their children wear them to be seen while trick-or-treating.  Do your students know the science behind them?  This chemical reaction produces light.  There is a lot going on in those little tubes.  Click the image to learn the science behind glow sticks and to try an experiment with students.


Have fun exploring evidence of a chemical change with students.  Try all of them or let the kids pick the one they want to try.



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