Goldenrod Paper = Bloody Handprints = Cool = Acids and Bases Lesson

Color changing goldenrod paper has been exciting students in chemistry! Imagine the enthusiasm of the first student or teacher who spilled a few drops of ammonia on a piece of yellow paper and observed it turn bright red! One can only image them exclaiming: “Super, Wow, Neat!!!”

Place the paper in a solution of household baking soda and the paper turns red; immerse it in vinegar and the red turns back to yellow! This goldenrod paper is colored with a dye that is an acid/base indicator: red in base and yellow in acid. The paper is similar to litmus paper that is blue in base and red in acid.

Even though color changing, goldenrod paper is no longer being manufactured, Educational Innovations, Inc. still has a supply and the paper is being sold in 100 sheet packages, (#SM-925). This special paper was being manufactured until June of 2008. At that time the process was changed to use a different dye that is more cost effective and better for the environment. Currently, paper of the same color, Galaxy Gold, is being offered by retail office supply stores, however, this paper uses a different dye and is not color changing.

Simple Activities With Goldenrod Paper

1. Write a “secret” message on the paper with paraffin or candle wax. The invisible message can be seen by spraying or wiping the paper with a weak basic solution e.g. ammonia (NH3 (aq)) or baking soda (NaHCO3). If you use ammonia solution, the message will disappear when the ammonia evaporates. If you use a baking soda solution, the message will remain.

2. Write a message on the paper using a cotton swab dipped into household ammonia. As the ammonia evaporates, the red message disappears.

3. Repeat Activity #2 using a cotton swab dipped into a solution of baking or washing soda. The message can be erased using vinegar (HAc) as “Yellowout .”

4. Use goldenrod paper to classify household products as acidic or basic. Solutions that turn yellow paper red are bases; solutions that turn red paper yellow are acids; and solutions that do not turn the color of either paper are considered “neutral.”

5. Tape a piece of yellow goldenrod paper to the board. Dip your hand into a shallow container of baking or washing soda and water. Then, when you press your hand against the paper, you will leave a “bloody” hand-print. Especially useful at Halloween. Compliments of Bob Becker 1985, Greenwich High School

6. Sponge the surface of a piece of goldenrod paper with a baking soda or washing soda solution and allow the wet, bright red paper to dry. Then, tape the paper to the board and press a hand that has been dipped into vinegar against the paper. The yellow hand-print will be the reverse or the “negative” of the result in activity #5. Complements of Carl Ahlers 2008, Australia

More Advanced Activities with Goldenrod Paper

7. Sponge a solution of baking soda or washing soda on a piece of goldenrod paper. Observe that the red color becomes gradually darker. Explain? Carl Ahlers has written: “Drying shifts the equilibrium in reaction 1 to the right as the H2CO3 is reduced due to the evolving of CO2 gas (reaction 2) (Le Chatelier). Subsequently more of the red Gol forms on drying. HGol (yellow) + HCO31- <—> Gol1- (red) + H2CO3 (aq) Reaction 1 H2CO3 (aq) <—> CO2 + H2O Reaction 2

8. Determine the equilibrium constant, the Ka, for this acid/base indicator. One way is to prepare a set of different pH solutions using a method of serial serial dilution on a spot plate or in small test tubes. Then, test to see at what pH the color change seems to occur for this indicator paper.

9. Make color-changing paper similar to goldenrod paper using household tumeric powder. Although tumeric is insoluble in water, in a workshop at Sacred Heart University, ca 1987, we discovered it was soluble in either ammonia or ethyl alcohol. White paper dipped in a solution of ammonia with dissolved tumeric will be dyed red which turns to yellow as the paper dries; dipped in a solution of tumeric and alcohol, the paper will remain yellow as it dries. When dry, test and observe how similar and how different the paper is from the color-changing goldenrod. Note: although this paper seems to react similar to color-changing goldenrod, the color fades much faster.

10. Prepare acid/base color changing paper using natural indicators: rose petals, purple cabbage, etc. Then determine the pKa of the paper.

Blood – A Model for Fifth Grade Students

 Fifth grade students will have a blast as they see this model of blood created.  The concept of a mixture can be covered as this model is made, as well as the concept of a solution can be described as students think of the blood found within their veins.

First we read A Drop of Blood by Paul Showers.  What an excellent book!  It was the perfect lead-in to building our own model of blood, which included plasma (Karo syrup), red blood cells (Red Hots candies), white blood cells (large lima beans) and platelets (split lentils):

We then drew a picture of our blood model and listed what each part does.

Now this is just Gross – Barf! – But Kids will love it!

Making a simulant is a form of chemistry, right? Here are instructions for making your own edible fake barf. Ick!

 

Here’s How:

1. Heat 1/4 cup of applesauce in the frying pan over low to medium heat.
2. Stir in 1 packet of unflavored gelatin.
3. Add a pinch or two of cocoa powder. Mix thoroughly and remove from heat.
4. Sprinkle oatmeal over the mixture into an aesthetically-pleasing chunky pattern. You can stir it in a bit, but don’t mix too much.
5. Repeat the oatmeal procedure with some raisin bran cereal.
6. Spread the barf mixture onto a plate so that it resembles vomit, adding extra raisins or cereal bits, as desired.
7. Allow the barf to cool completely (couple of hours). Remove it from the plate with a spatula.
8. Have fun!

Tips:

1. You may wish to spray your plate with nonstick cooking spray to keep the vomit from sticking.
2. Adult supervision is recommended.
3. Please let me know if you come up with alterations to this recipe that make it even more realistic.

What You Need:

• 1 pkg unflavored gelatin
• applesauce
• powdered cocoa
• oatmeal
• raisin bran cereal
• frying pan
• kitchen utensils

Halloween Science – Ghost Snot

What a great way to teach kids about mixtures – in this case – would be classified as a solution.  GHOST SNOT

One is for older kids since Borax is poisonous if ingested, so please don’t allow young children to handle it, and one is for young kids and is Borax free.

For the Older Kids

What you will need:

• Borax Laundry Detergent
• Water
• Elmer’s Glue
• Sandwich Bag
• Food Coloring

What you need to do:

1. Take 1/8th of a cup of borax laundry detergent and dissolve it into a half litre of warm water.
2. Once it is dissolved, set it aside and allow it to cool.
3. Take a separate cup and add 2 tablespoons of Elmer’s glue in it.
4. Stir in 3 tablespoons of water and mix thoroughly.
5. Add food coloring.  Green is the best choice for snot but you can mix it up for alien or ghost goo. (hmm, I think that is the official term for it). Stir until you have the desired color.
6. Pour in one tablespoon of the borax solution that you made.
7. Mix thoroughly.

And there you have some really gross snot.  Enjoy

For the younger kids

What you need:

• clear corn syrup
• water
• clear gelatin powder
• food coloring

What you need to do:

1. Heat a half cup of water until it is boiling hot (this is important for parents to do.)
2. Add in three packages of clear gelatin and food coloring
3. Stir until it is dissolved.
4. Place into a measuring cup
5. Pour in corn syrup until the liquid rises to a cup. 
6. Stir until long snot globs form on the end of your fork.

And there you have a non toxic snot that you won’t have to worry if any is ingested. 

I hope you enjoyed today’s gross crafty recipe.