Halloween Candy Investigation

Reynolds 2011

This time of year….

• Sugar, candy, junk food, and chocolate are very common.

Let’s test some oldcandy that you don’tsee much of these days.

Pop Rocks® vs. Zotz®• Well- the knock off kind at least…. These are

the originals.

Set up your Journal

Add a chart like this:

Then leave room on your page to draw and write explanations & inferences:

How it looks How it feels How it Reacts w/ H2O

How it tastes & acts in mouth

Zotz®

Pop Rocks®

Follow The Steps:

1. Open a Zotz® candy2. Write & Draw what Zotz® look like3. Add a few drops of water to the Zotz ®.

Record your observations and explanation for what has happened.

Follow The Steps:

4. Suck on the Zotz® or Bizzerks® candy without biting it.

5. Record your observations in your journal

Follow The Steps:

6. Open the Pop Rocks® and place a few of the rocks on the paper towel. Write & Draw your observations in your journal.

7. Add a few drops of water. Record your observations.

Follow The Steps:

8. Hold a few Pop Rocks® in your hand; close your hand and record your observations.

9. Put some of the Pop Rocks® in your mouth. Do not chew. Record your observations.

10. Write an inference for your observations.

11. Add an investigable question to your list.

Questions1. Which type of candy produced a physical

change? 2. How do you know?

3. Which type of candy produced a chemical change?

4. How do you know?

ExplanationsThe active ingredients in Zotz® candies are sodium bicarbonate, tartaric acid, and citric

acid in the dry form. Sodium bicarbonate is baking soda. Citric acid is found in citrus fruits. Tartaric acid is found in many fruits; cream of tartar, derived from the fermentation of wine, is potassium salt of tartaric acid. When these ingredients are combined with water, chemical reaction that produces carbon dioxide gas takes place.

The popping sensation observed in the activity resulted when the sodium bicarbonate reacted with the two acids to form carbon dioxide bubbles, which break on the tongue. However, the reaction did not occur until water (or saliva) was added. The water dissolved the solids and allowed them to react with one another to form the new product, carbon dioxide. It is a chemical change, or reaction.

Pop Rocks® do not contain sodium bicarbonate or either of the acids found in the other candies. The pop that results is caused by the release of carbon dioxide bubbles that are encapsulated within the candy. Addition of water weakens the structure of the solid, allowing the gas to break through and cause the pop. This is a physical change, rather than a chemical reaction, because no new products are formed.