Data with cheese on top.

Now your science project is really starting to cook and you're hungry for some action. But first, take a break--a pizza break. A glance at our menu will help you organize and rnake sense of your findings so you can share them with the world.

APPETIZERS

The first step: Set the table--a data table, that is. A data table gives you a place to record your findings (your data) while you do your experiment. That's a whole lot better than scribbling numbers on a sticky napkin and trying to organize everything later, isn't it? So get out some paper and pencils and let's get started.

Say you're planning to experiment on pizza cheese. After watching those goofy "Pizza! Pizza!" commercials on TV, you want to know how far pizza cheese really stretches. And because you're watching your waistline, you want to know if low-fat and no-fat mozzarella cheeses stretch as far as the regular, full-fat kind.

On your data table, you'll want to include all the variables in your I experiment--your independent variable (fat content), all the levels of your independent variable (no-fat, low-fat, and regular-fat cheese), and your dependent variable (stretch length).

Once your table is set, you're ready to start your experiment and fill in the blanks with data. Follow the ingredients list and recipe for the "Minipizza Stretch Test" below.

THE MAIN COURSE

When you're finished with the experiment, you'll have a table (and data table) full of cheesy data. But all those numbers might be hard to swallow unless you turn them into something more appetizing. How about a picture--a graph? Graphs can help you see trends in your data that might otherwise be hard to spot.

The kind of graph you make depends on your data. For the cheese experiment above, a line graph would be best That is because the independent variable (cheese fat content) is a continuous variable. In other words, though you only tested no-fat (0 percent), low-fat (2 percent), and regular-fat (4 percent) cheese, there could be other amounts of fat in between (e.g., 1 percent and 3 percent). A graph made of a continuous line can help you estimate what the stretch length would be for those in-between values.

But what if you decide to continue your experiment by testing the stretchability of different brands of no-fat mozzarella? Your independent variable has now changed from fat content to brand.

Cheese brand is a discrete variable, a variable that comes in different kinds with no "values" in between kinds. For a discrete variable, a bar graph works best. On this type of graph, the result for each value of the independent variable is represented by a separate (discrete) bar.

A PIE TO GO

As you finish up your graphs and munch your last bite of pizza, you wonder: Do people really buy no-fat mozzarella cheese? To find out, you conduct a survey of shoppers at the local grocery store. Your survey results: 30 percent of the shoppers buy regular-fat mozzarella; 45 percent buy low-fat cheese; and 25 percent buy the no-fat kind.

To show viewers exactly what these data mean, make a pie. No, not another pizza--a pie chart. That's the best way to present data that are percentages of a whole.

A pie chart is basically a circle divided into pie slices--kind of like slices of pizza (or apple pie, if you're ready for dessert). The trick is that the size of each "Piece" represents a piece of data. So the slice for regular-fat cheese should take up 30 percent of the circle and so on.

STOMACH SETTLER

If all this info is making your stomach turn, relax. You don't have to swallow it in one sitting. You can always turn the page and review our menu of data-display choices after you finish your project.

Who knows? Maybe you'll even think of other creative ways to display your data--in pictures, maps, or charts. Just remember the ultimate goal: to help you understand the research you did--and to make others want to eat it up.

MINIPIZZA STRETCH TEST

INGREDIENTS (WHAT YOU NEED): nine pieces of bread or English-muffin halves * toaster * equal amounts of the same brand of no-fat, low-fat, and regular-fat shredded mozzarella cheese * tomato sauce (optional) * tablespoon * baking sheet * oven * pot holder * fork * meterstick

THE RECIPE (WHAT TO DO):

1. Preheat oven to 400[degrees]F (ask an adult to help you).

2. Toast bread slices evenly and cool to room temperature. Spread two tablespoons of tomato sauce on each (optional).

3. Divide shreds of the first kind of cheese you'll test into three equal piles.

4. Sprinkle three toast slices evenly with equal amounts of cheese.

5. Place one "minipizza" on baking sheet in preheated oven for eight minutes.

6. Remove (use a pot holder). Have partner hold meterstick perpendicular to baking sheet, next to pizza, "zero" end down. Immediately prick cheese with a fork and pull straight upward (at a slow, steady speed). Partner should measure how far the cheese stretches before breaking or falling apart. Record result in data table.

7. Repeat Steps 5 and 6 twice more with next two toast slices (same cheese).

8. Repeat Steps 3 through 7 with the other types of cheese.

TOTALLY COOL CAREER

JOHN JAEGGI MAKES AND STRETCHES PIZZA CHEESE

John Jaeggi is a cheese maker at the University of Wisconsin Center for Dairy Research. "I do research on a wide variety of cheeses," he says. Right now, his focus is on mozzarelia. "We're trying to develop a low-fat cheese that will have the same stretch and meltability you would find in [regular-fat] mozzarelia cheese." To pizza makers, the way the cheese melts and stretches is just as important as the toste, Joeggi says. To find out if the low-fat cheeses he produces make the grade, Jaeggi does tests like he experiments on these pages. His words of wisdom: "We compare every [new cheese variety] against a control," say, a regular-fat mozzarelia hat other cheeses can be rated against. Jaeggi says it's important to do the stretch test as soon as the cheese mes out of the oven cause "the longer you it, the less the cheese ill stretch." And, he adds, e type of oven you use (e.g., conventional or microwave) "can couse four cheese to react in totally different ways." (More variables you can experiment with!) How did Jaeggi get stuck on cheese? "My father and grandfather were in the cheese business, and I just followed along," he says. Though Jaeggi studied business and economics in college, he worked in the family factory, gaining hands-on experience making cheese. He later took courses to learn more about his tasty field. "A good chemistry background and biology and microbiology courses definitely help," he says.

For more information about careers in food science, write:

Undergraduate Advisor Dept. of Food Science & Technology University of California Davis, CA 95616

TO MAKE A DATA TABLE:

1. Give your table a title that clearly identifies the variables you are investigating.

2. Label the first vertical column on the left with your independent variable (cheese fat content).

3. Underneath that heading, list the levels of the independent variable (e.g., no-fat, low-fat, regular-fat).

4. Now label the next column with the dependent variable (stretch length).

5. Below that heading, draw blank boxes where you can record the result for each trial, or test, of each type of cheese.

6. You might also want to include a column at the for right where you figure out the average stretch for each cheese (the total for all trials with that cheese, divided by the number of trials).

TO MAKE A LINE GRAPH

1. On a piece of graph paper, draw a set of axes.

2. Place labels for the levels of your independent variable along the horizontal (x) axis.

3. Place a scale that includes all the values of your dependent variable on the vertical (y) axis.

4. Label the axes with the nomes of your variables.

5. Now plot a point on the graph for each piece of data. For example, say the average stretch length for no-fat cheese was 10 cm. Directly above the x-axis label for no-fat cheese, plot a point at the level of the y-axis 10 cm mark. Do the same for the average value for each kind of cheese.

6. Then connect the points. (Rather than connecting the data points, scientists sometimes draw a line of best fit, which shows the general trend the data follow. A line of best fit is often curved.

7. Give your finished graph a title.

TO MAKE A BAR GRAPH:

1. On a piece of graph paper, draw set of axes. 2. Place labels for the levels of your dent variable along the horizontal (x) axis.

3. Place a scale that includes all your dependent variabie on (y) axis.

4. Label the axes with the names of your variables.

5. For each level of the independent variable, draw a solid bar that rises to the height of the corresponding value of the dependent variable. For example, say the overage stretch length for Cheesola cheese was 25cm. Draw a bar above the Cheesola label that reaches the 25cm mark on the y axis. Leave an equal amount of space between each bar so your graph is easy to read.

6. Give your finished graph a tide.

TO MAKE A PIE CHART:

1. Draw a circle with a compass.

2. Mark the center with a point, this is where each pie "slice" will start.

3. To figure out how big to make each wedge, convert your data from percentages to angle degrees. A full circle can be divided into 360 degrees. So, for example, if 25 percent of shoppers bought no-fat cheese, the pie wedge for no-fat should 25 percent of the 360 degrees, or 90 degrees

4. To measure the wedge, position a protractor at the center point, mark the angle by placing points on the edge of the circle (or beyond it).

5. Draw a line from each of these points to the center of the circle.

6. Label the wedge (include its percentage).

7. Start measuring your next wedge from the edge of the first so the slices do not overlap. When you're done, the entire circle should be filled. if not, check your math (all angles should add up to 360 degrees), and measure again.

8. Give your finished chart a title.