Sunday, November 22, 2009

Sour Jacks

We bought a bag of Sour Jacks on clearance after Halloween and have enjoyed testing them for acid. It wasn't until three weeks later that we actually tested them--they're hardly sour at all! No wonder the bubbles don't last very long.

Helper

Our eighteen-month-old wants to get in on the action of candy experiments. She loves stirring.

Questions

Simple questions can be surprisingly difficult to answer. This week's task has been trying to figure out how to explain "Why does water make sugar sticky?" I looked through at least 20 chemistry textbooks at the library, but "sticky" isn't in the index. (Stereoisomers, stoiciometry, and sucrose, however, all made several appearances.)

Skittles Rainbow

Several people have contacted me to say they would like to do the Density Rainbow at a party or a class presentation, but they can't make all the Skittles dissolve in time. The easiest fix for this problem is to microwave each solution for about 30 seconds and give it a stir; this should dissolve the rest of the candy. If you don't have access to a microwave, try this:

1. Fill five glasses with 3 TBSP water each. Use warm water if you can.
2. Add your Skittles to the water, each color in a different cup. Use
  • 20 purple Skittles
  • 15 green Skittles
  • 10 yellow Skittles
  • 5 orange Skittles
  • 1 red Skittle
3. As soon as the shell on the red Skittle dissolves, take the Skittle out of the colored water.
4. Check your other solutions to make sure the candy has dissolved. (The ones with the most Skittles will take the longest to dissolve.) If it's time to do the rainbow and one of your solutions isn't ready, start with the next color of the rainbow.
5. Pour your rainbow with the purple on the bottom and the red on the top.

If you need a backup:
The Density Rainbow is tricky, and can be ruined if you pour too fast or if somebody jostles your elbow. In case this happens, prepare a second set of solutions. Since you'll have lots of reds and oranges left over, but not a lot of purple, use the Skittles in reverse order (20 red/15 orange/10 yellow/5 green/1 purple). Pour your rainbow as above.

Monday, November 2, 2009

Chocolate Bloom

Chocolate is made of cocoa butter, cocoa solids, and other ingredients that have been mixed together. Can you take them apart?


(Chocolate after several weeks in a warm car)
What you need:
  • Chocolate candy
  • Heat
What to do:
  1. Heat your chocolate in a sunny windowsill, with a hair dryer, or in a low oven, until it starts to melt.
  2. Let it cool overnight or in the refrigerator.
  3. Repeat these steps until you see light brown spots or streaks. (This may take several heating attempts.)
What's happening:
When the chocolate heats and cools, the cocoa butter starts to separate from the rest of the chocolate. This forms the light brown layer.

Acid Test (Soda)

Sour taste is the body's way of identifying acid, so if your candy tastes sour, it contains acid. To test for acid yourself, try this:

What you need:
  • Fruit-flavored or sour candy, such as LemonHeads, Nerds, Skittles, StarBurst, or Sweet Tarts
  • Baking soda

What to do:
  1. Dissolve the candy in a half-cup of water.
  2. Sprinkle a spoonful of baking soda into water.
  3. Watch for bubbles. If it bubbles, the candy is acidic.

What's happening:
When you dissolve acidic candy in water and add baking soda, the reaction produces carbon dioxide gas. This is what makes the bubbles.