The Popcorn Lab! What do you think is going to happen to the density of a given sample of popcorn as it is popped?

Transcription

1 The Popcorn Lab! Problem: What do you think is going to happen to the density of a given sample of popcorn as it is popped? Background: Biblical accounts of "corn" stored in the pyramids of Egypt are misunderstood. The "corn" from the bible was probably barley. The mistake comes from a changed use of the word "corn," which used to signify the most-used grain of a specific place. In England, "corn" was wheat, and in Scotland and Ireland the word referred to oats. Since maize was the common American "corn," it took that name -- and keeps it today. It is believed that the first use of wild and early-cultivated corn was popping. The oldest ears of popcorn ever found were discovered in the Bat Cave of west central New Mexico in 1948 and Ranging from smaller than a penny to about 2 inches, the oldest Bat Cave ears are about 4,000 years old. Popcorn was integral to early 16th century Aztec Indian ceremonies. In 1519, Cortes got his first sight of popcorn when he invaded Mexico and came into contact with the Aztecs. Popcorn was an important food for the Aztec Indians, who also used popcorn as decoration for ceremonial headdresses, necklaces and ornaments on statues of their gods, including Tlaloc, the god of rain and fertility. An early Spanish account of a ceremony honoring the Aztec gods who watched over fishermen reads: "They scattered before him parched corn, called momochitl, a kind of corn which bursts when parched and discloses its contents and makes itself look like a very white flower; they said these were hailstones given to the god of water." Writing of Peruvian Indians in 1650, the Spaniard Cobo says, "They toast a certain kind of corn until it bursts. They call it pisancalla, and they use it as a confection." The use of the moldboard plow became commonplace in the mid-1800s and led to the widespread planting of maize in the United States. Popcorn was very popular from the 1890s until the Great Depression. Street vendors used to follow crowds around, pushing steam or gas-powered poppers through fairs, parks and expositions. During the Depression, popcorn at 5 or 10 cents a bag was one of the few luxuries down-and-out families could afford. While other businesses failed, the popcorn business thrived. An Oklahoma banker who went broke when his bank failed bought a popcorn machine and started a business in a small store near a theater. After a couple years, his popcorn business made enough money to buy back three of the farms he'd lost. During World War II, sugar was sent overseas for U.S. troops, which meant there wasn't much sugar left in the States to make candy. Thanks to this unusual situation, Americans ate three times as much popcorn as usual. Popcorn went into a slump during the early 1950s, when television became popular. Attendance at movie theaters dropped and, with it, popcorn consumption. When the public began eating popcorn at home, the new relationship between television and popcorn led to a resurge in popularity.

2 Microwave popcorn - the very first use of microwave heating in the 1940s - has already accounted for $240 million in annual U.S. popcorn sales in the 1990s. Americans today consume 17 billion quarts of popped popcorn each year. The average American eats about 54 quarts. Hypothesis: Write a hypothesis below describing what you think will happen to the density of your sample of popcorn. Make sure you phrase it as a testable, if-then statement. Think carefully about this you will be graded on the quality of your hypothesis! Materials: Make a list of the materials you are using in this lab. Procedure PART 1: 1. You will be given 3 SAMPLES of unpopped popcorn. Measure and record the mass of your 3 SAMPLES of unpopped popcorn in data table 1 below. Measure the mass in grams. 2. Measure and record the volume of your 3 SAMPLES of unpopped popcorn in data table 1 below. Measure the volume in ml using a graduated cylinder. 3. Calculate the densities of your 3 SAMPLES of unpopped popcorn in the calculations section below, and then record the densities in data table 1 below. What unit will your density be in? DATA TABLE 1 MAKE SURE ALL OF YOUR MEASUREMENTS HAE UNITS! Measurement Unpopped corn Sample #1 Unpopped corn Sample #2 Unpopped corn Sample #3 Mass (g) olume (ml) Density (g/ml)

3 Calculations: DATA TABLE 2 Density Unpopped corn Sample #1: m = Calculations: Calculate the % change in mass BELOW as a result of chewing the gum. Density Unpopped corn Sample #2: m = Density Unpopped corn Sample #3: m = Procedure PART 2: 1. Pop your 3 SAMPLES together in the popcorn maker. When they are done, put them into your bowl to get ready to eat. BEFORE YOU EAT THE POPCORN, MAKE SURE YOU TAKE 2. THE FOLLOWING MEASUREMENTS: 3. Scoop out three DIFFERENT SMALL CUPS of popcorn to measure. Mr. Jauss will give you three cups to use. 4. Measure and record the mass of your 3 SAMPLES of popped popcorn in data table 2 below. Measure your mass in grams. 5. Measure and record the volume of your 3 SAMPLES of popped popcorn in data table 2 below. Measure your volume in ml. 6. Calculate the densities of your 3 SAMPLES of popped popcorn in the calculations section below, and then record the densities in data table 2 below. What unit should you measure your density in? Once you have recorded this data, EAT YOUR POPCORN! DATA TABLE 2 - MAKE SURE ALL OF YOUR MEASUREMENTS HAE UNITS! Measurement Popped corn Sample #1 Popped corn Sample #2 Popped corn Sample #3 Mass (g) olume (ml) Density (g/ml) Calculations: Density Popped corn Sample #1: m = DATA TABLE 2 Density Popped corn Sample #2: m = Density Popped corn Sample #3: m =

4 Graphs: ATTACH YOUR GRAPHS TO YOUR LAB REPORT! Make TWO GRAPHS one for your unpopped popcorn, and one for your popped popcorn. You are going to use Logger Pro again Yeah! You want to put volume on the x-axis, and mass on the y-axis. Make sure you use the right units for both! Follow the directions you used before, but do not choose bar graph instead, when you double click on the graph, choose point protectors, and click OFF connect points. Make sure you autoscale from zero the graph again, by clicking on the Axes Options button. Enter in your volumes in the x column, and enter in your masses next to then in the y column. Make sure they are in increasing order from small to large! After you have entered in your data, go to Analyze, and select Linear Fit. Then, make sure you title your graph! Do the same thing for your popped popcorn data you will have two graphs total! Conclusions: 1. Look at your graphs and your calculations. Which had a greater density your unpopped popcorn or your popped popcorn? Write one detailed sentence why this was! Think mass and volume! 2. What happens to the mass of the popcorn as it is cooked? Write one detailed sentence that explains why this happens! 3. What happens to the volume of the popcorn as it is cooked? Write one detailed sentence that explains why this happens!

5 4. Why, for all of your unpopped and popped popcorn samples, were the densities pretty close to the same, even though the popcorn samples you tested were different sizes meaning, they had different weights and volumes? 5. Calculate the average density of your unpopped popcorn by adding the densities together and dividing by three: + + / 3 = 6. Calculate the average density of your popped popcorn by adding the densities together and dividing by three: + + / 3 = 7. Look closely at your graphs you have mass and volume graphed on them! You have the points put onto a straight line. What does the slope of each line tell us in this lab? Hint think rise over run, or mass over volume! 8. Look at the slope of the line for your unpopped popcorn graph. What is it meaning, what number is it? This is the density of your unpopped popcorn. Is it close to what you calculated above in problem #5? Why should these numbers be pretty much the same?

6 9. Look at the slope of the line for your popped popcorn graph. What is it meaning, what number is it? This is the density of your popped popcorn. Is it close to what you calculated above in problem #6? Why should these numbers be pretty much the same? 10. When taking the volume of your popped popcorn, what did you find was the greatest source of error in figuring out the volume?