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Can You Do the Mentos Trick with Regular Soda?

Wednesday April 16, 2014
Mentos Trick (Anne Helmenstine)Sometimes I take for granted what works and what doesn't work with science tricks. For example, there is the Mentos trick, where you drop a tube of Mentos candies into a bottle of soda to get a Mentos geyser. Typically this is done using Diet Coke or Diet Pepsi, but do you know whether it works with regular soda?... Find out

Atomic Structure and Periodic Table Quiz

Wednesday April 16, 2014
This quiz is a little more challenging than the atom basics quiz or atomic structure quiz I've had up. The atomic structure and periodic table quiz targets AP chemistry and first year college chemistry concepts. It's multiple choice and you don't need a calculator or any scratch paper. I provided a link to the periodic table, since it will help you answer some of the questions. Are you ready to try the quiz?

This Day in Science History - April 16 - Joseph Black

Tuesday April 15, 2014
William Ramsay/The Gases of the Atmosphere 1896 April 16th marks the birthday of Scottish chemist Joseph Black.

Black is considered one of the founders of thermochemistry. He was the first to note that melting ice does not change in temperature and postulated the idea of latent or specific heat. He also did research on carbon dioxide or what he called 'fixed air'. When he managed to separate it from normal air, it helped the argument that air was not an element, but a mixture of elements and molecules.

Find out what else occurred on this day in science history.

Make Copper Sulfate

Tuesday April 15, 2014
Copper Sulfate Crystals (Stephanb, Creative Commons)Copper sulfate crystals are among the most beautiful crystals you can grow, but you might not have access to a chemistry lab or want to order the copper sulfate from a chemical supply company. That's okay, because you can make copper sulfate yourself using readily-available materials.

Materials for Making Copper Sulfate

There are actually a few different ways you can make copper sulfate yourself. This method relies on a little electrochemistry to get the job done. You will need:

  • copper wire - which is high purity copper
  • sulfuric acid - H2SO4 - battery acid
  • water
  • 6-volt battery
Make Copper Sulfate
  • Fill a jar or beaker with 5 ml concentrated sulfuric acid and 30 ml of water. If your sulfuric acid solution is already diluted, add less water.
  • Set two copper wires into the solution so that they are not touching each other.
  • Connect the wires to a 6-volt battery.
  • The solution will turn blue as copper sulfate is produced.
When you run electricity through copper electrodes which are separated from each other in a dilute sulfuric acid bath the negative electrode will evolve bubbles of hydrogen gas while the positive electrode will be dissolved into the sulfuric acid and oxidized by the current. Some of the copper from the positive electrode will make its way to the anode where it will be reduced. This cuts into your copper sulfate yield, but you can minimize the loss by taking some care with your set-up. Coil the wire for the positive electrode and set it at the bottom of your beaker or jar. Slip a piece of plastic tubing (e.g., a small length of aquarium hose) over the wire where it extends up from the coil to keep it from reacting with the solution near the anode. (If you had to strip your wire, just leave the insulating coating on the part that runs down into the liquid). Suspend the negative copper electrode (anode) over the cathode coil, leaving a good amount of space. When you connect the battery, you should get bubbles from the anode, but not the cathode. If you get bubbling at both electrodes, try increasing the distance between the electrodes. Most of the copper sulfate will be at the bottom of the container, separated from the anode.

Collect Your Copper Sulfate

You can boil the copper sulfate solution to recover your copper sulfate. Because the solution contains sulfuric acid, you won't be able to boil the liquid off completely (and you need to take care not to touch the liquid, which will become concentrated acid). The copper sulfate will precipitate out as a blue powder. Pour off the sulfuric acid and reuse it to make more copper sulfate!

If you would prefer to have copper sulfate crystals, you can grow them directly from the blue solution that you prepared. Just allow the solution to evaporate. Again, use care in recovering your crystals because the solution is very acidic.

This Day in Science History - April 15

Monday April 14, 2014
April 15th is tax day in the United States.

It is also the birthday of Leonardo Da Vinci, three Nobel Prize winners and two other prominent scientists. Find out who they are and what else occurred on this day in science history.

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How Safe Are Sparklers on Cake?

Monday April 14, 2014
Sparkler on Cake (Getty Images)You know how I love fire, so I don't consider a cake completely decorated until it has at least one sparkler! Yet, just how safe are pyrotechnics on your food? Here's a look at the health risks from sparklers. In a nutshell, use them, but buy the kind meant for food... Learn more

Make Your Own Easter Egg Dyes

Monday April 14, 2014
Colored Easter Eggs (Steve Cole, Getty Images)You have the ingredients to make your own natural Easter egg dyes in your kitchen and garden. Dyeing eggs using colors you made yourself is a fun pigment chemistry project, plus you'll save money that you can apply toward chocolate Easter bunnies!

Unless you want to make Easter stink bombs, you won't want to color hard-boiled eggs today. Why not make Easter decorations by dyeing hollow eggs? To make colored hollow eggs, first you need uncooked eggs (you'll probably burst a blood vessel trying to empty a hard-boiled egg this way). Take a pin, sharp nail or awl, and work a hole into one end of the egg. Turn it over and repeat the process. Larger holes make it easier to remove the contents of the egg, but are also more obvious. Place the egg over a bowl, blow through one hole to force the contents out the other hole. Rinse off the egg and allow it to dry. Make scrambled eggs, if you like. Note: this can be a time-intensive process and is easier for an adult than a child.

Next, make dyes and color your eggs. The dyes are generally non-toxic and safe for kids to make and use, plus you can think about pigments (molecules that have color) and mordants (molecules that bind in a reaction to intensify color or make the dye more colorfast).

This Day in Science History - April 14 - Christiaan Huygens

Sunday April 13, 2014
April 14th is the birthday of Christiaan Huygens. Huygens was the champion of the wave nature of light at the time Newton was arguing the corpuscular nature of light. Is light a particle or a wave or both? The answer would lead to many of the discoveries of early 20th century science.

Find out what else occurred on this day in science history.

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Carbonated Ice Cream Recipe

Sunday April 13, 2014
This chocolate ice cream is bubbly and carbonated because it was frozen using dry ice. (Anne Helmenstine)Have you tried fizzy ice cream? It has the flavor and bubbles of an ice cream float without the soda. It's an extremely easy recipe to try. It doesn't even require a freezer; you just need dry ice. I've had a recipe for vanilla dry ice ice cream up for a while, but here's a chocolate recipe, along with a few tips and tricks I learned making the ice cream:

Carbonated Ice Cream Ingredients
  • 2 cups heavy cream
  • 2 cups half and half
  • 1 cup chocolate syrup
  • 1/2 cup sugar
  • 1 teaspoon vanilla
  • 1/8 teaspoon salt
  • dry ice
Make Dry Ice Ice Cream
  1. You'll get a better texture for your ice cream if you crush your dry ice. The easiest way to do this is to put the dry ice into a paper bag and smash it with a mallet or walk on the bag. The ice crushes easily so you don't have to get medieval on it.

  2. In a very large bowl, mix all of the ingredients except for the dry ice.

  3. Stir in the dry ice a little at a time. "A little at a time" is the key point here, because if you add a lot of dry ice at once you'll get mountains of bubbles that will overflow your bowl. The bubbling will continue as long as any dry ice remains.

  4. I actually liked the partly-frozen, partly-bubbly ice cream, but you can continue to add dry ice until you get a solid ice cream. The ice cream will be very cold, so be careful when eating it.

  5. You can store uneaten ice cream in the freezer.
The dry ice sublimates to form carbon dioxide gas. The carbon dioxide is perfectly safe... you drink it in soda all the time. The only risks from the recipe are weight gain (not exactly a low-cal, low-fat recipe) and frostbite (use gloves if you plan to handle the dry ice and don't eat dry ice chunks). If you have leftover dry ice, there are many other projects you can try.

Water into Wine Chemistry Demonstration

Sunday April 13, 2014
Water into Wine Demo (andrea, morguefile.com)Are you looking for an Easter chemistry demonstration that doesn't require a special kit, hard-to-locate items, or toxic chemicals? The water into wine demonstration turns a clear liquid into a red liquid, then back to clear again. This demonstration can be used to illustrate the properties of acid-base indicators. Try it out...
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