Friday, November 13, 2009

Make Silver Polishing Dip


As silver oxidizes it will tarnish. This layer of oxidation can be removed without polishing and scrubbing by simply dipping your silver in this non-toxic electrochemical dip. Another big advantage to using a dip is that the liquid can reach places a polishing cloth cannot.
You can use chemistry to removethe tarnish
from your silver without even touching it.
Mel Curtis, Getty Image


Difficulty: Easy
Time Required: Minutes

Here's How:

  1. Line the bottom of the sink or a glass baking dish with a sheet of aluminum foil.
  2. Fill the foil-lined container with steaming hot water.
  3. Add salt (sodium chloride) and baking soda (sodium bicarbonate) to the water. Some recipes call for 2 tsp baking soda and 1 tsp salt, whereas others call for 2 tablespoons each of baking soda and salt. Personally, I wouldn't measure the amounts... just add a bit of each substance.
  4. Drop the silver items into the container so that they are touching each other and resting on the foil. You will be able to watch the tarnish disappear.
  5. Leave heavily tarnished items in the solution for as long as 5 minutes. Otherwise, remove the silver when it appears clean.
  6. Rinse the silver with water and gently buff it dry with a soft towel.
  7. Ideally, you should store your silver in a low-humidity environment. You can place a container of activated charcoal or a piece of chalk in the storage area to minimize future tarnish.

Tips:

  1. Use care when polishing or dipping silver plated items. It is easy to wear away the thin layer of silver and cause more harm than good through overcleaning.
  2. Minimize exposing your silver to substances which contain sulfur (e.g., mayonnaise, eggs, mustard, onions, latex, wool) as the sulfur will cause corrosion.
  3. Using your silver flatware/holloware or wearing silver jewelry helps to keep it free from tarnish.

What You Need:

  • Sink or glass pan
  • Hot water
  • Baking soda
  • Salt
  • Aluminum foil
  • Tarnished silv

Sulfur Pentafluoride: The Color of Love... and Death

Here's a cute cartoon to brighten your day. Sulfur pentafluoride presumably binds with itself to make disulfur decafluoride, a chemical warfare pulmonary agent similar to your good old friend phosgene. Fun stuff. Disulfur decafluoride eventually decomposes into sulfur hexafluoride (which can be used as a sort of anti-helium in gas density demonstrations) and sulfur tetrafluoride (which reacts with moisture in the air to form sulfurous acid and hydrofluoric acid). Incidentally, while I have no idea about the color of sulfur pentafluoride, I can tell you disulfur decafluoride is colorless and one breath can kill you in a day. It takes a while because its actually the acids produced by the sulfur tetrafluoride reacting with water that likely do you in.

How to Make Ink - Easy Ink Recipes


One of my self-improvement projects has been to try to learn how to write legibly. It would be easy to blame my handwriting on being left-handed, but it probably has a lot more to do with trying to write quickly rather than neatly. So, I got a pen and some ink and have been practicing.

Ink is one of the practical contributions of chemistry. You can make invisible inks and tattoo inks in addition to writing and drawing inks. Although ink recipes may be closely-guarded secrets, the basic principles of preparing ink are simple. You want to mix a pigment with a carrier (usually water). It helps to include a chemical which will allow the ink to flow fluidly and adhere to the paper (gum arabic). Here are some easy ink recipes to get you started ma

Black Permanent Ink

  • 1/2 tsp lamp black (which you can buy or can make by holding a plate over a candle and collecting the soot or from collecting other char)
  • 1 egg yolk
  • 1 tsp gum arabic
  • 1/2 cup honey
Mix together the egg yolk, gum arabic, and honey. Stir in the lamp black. This will produce a thick paste which you can store in a sealed container. To use the ink, mix this paste with a small amount of water to achieve the desired consistency.

Brown Ink

  • 4 teaspoons loose tea or 4-5 teabags
  • 1 teaspoon gum arabic
  • 1/2 cup boiling water
Pour the boiling water over the tea. Allow the tea to steep for about 15 minutes. Squeeze as much tea (tannin) as possible from the tea or teabags. Stir in the gum arabic. Strain the ink and allow it to cool before bottling it.

Prussian Blue Ink

  • Prussian Blue pigment (sometimes sold as laundry bluing)
  • water
Mix the pigment into the water to achieve a rich blue ink.

Unless you happen to have a calligraphy pen, the easiest way to use these inks is with a homemade quill or a paintbrush. If you have recipes for inks you would like to share, feel free to post them.



Make an Acid-Base Rainbow Wand

Here's an easy and colorful chemistry demonstration for you. Take a long glass tube and fill it with Universal Indicator solution. Add a few drops of 0.02M HCl to one end of the tube and seal it with a stopper. Add a couple of drops of 0.02M NaOH to the other end of the tube and seal it. The Universal Indicator will respond to the pH gradient by providing you with a lovely rainbow. You can invert the tube a few times to speed things up.

You can get a similar result using home chemistry. Fill a clear straw with red cabbage juice. Add a little lemon juice or vinegar to one end of the straw. Add a few drops of baking soda or laundry detergent solution to the other end of the straw.

On This Day in Science History - November 13

November 13th is Edward Doisy's birthday. Doisy was an American biochemist who shared the 1943 Nobel Prize in Medicine with Henrik Dam for their work concerning vitamin K. Dam discovered the vitamin and Doisy identified, isolated, determined the structures, and synthesized of two different forms of vitamin K.

Vitamin K is actually a group of vitamins named after "Koagulations-Vitamin" in German because they are required for processes of blood coagulation. They are also involved in the process of binding calcium during bone metabolism. Deficiency is rare in adults, but newborns have a higher risk, and an injection of vitamin K1 is recommended by the American Academy of Pediatrics shortly after birth. Other research into the K vitamins is looking at links between vitamin K and bone health, Alzheimer's disease, and certain cancers.

Chemistry Gift Ideas

Three of my children have birthdays in November, so I've already got a jump on holiday shopping ideas. I have a few different gift lists that I use to jog my memory when I need ideas. Top Science Toys is an all-inclusive collection of fun and educational science toys and gadgets. I also have a list of gifts you can make by applying your command of chemistry.





This year I've added a new list to the collection: Chemistry Gift Ideas. These are gifts someone with a love of chemistry would especially enjoy. With the possible exception of a chemical volcano, chemistry gifts are a little harder to find in stores than other gifts. Most of the online retailers offer overnight shipping so even if you wait until the last minute for your holiday shopping, you'll still find the perfect present!

Plasma Ball




A plasma ball is one of the cool items that made my Top Science Toys list.

Carbon - Diamond Crystal


A diamond crystal is a
form of elemental carbon.
USGS