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harum.koh/Wikimedia Commons April 28 & May 12, 2018 Fight Like an Animal

April 28 & May 12, 2018 Fight Like an Animal

About the Issue

Science News article(s): “Fight like an animal”

Readability score: 8.5

Science News for Students article(s): “Fighting ‘like an animal’ may not be what you expect”

Readability score: 7.5

The article “Fight like an animal” describes strategies that animals have developed to fight their same- species rivals. Students can focus on information reported in the article, follow connections to earlier articles about animal weaponry and pursue cross-curricular connections in experimental design, biology and engineering.

This experimental design–focused guide is inspired by the Intel International Science and Engineering Fair — the world’s largest international pre-college science competition that brings together approximately 1,800 high school students from more than 75 countries. During Intel ISEF, held this year in Pittsburgh, from May 13 to May 18, students showcase their independent research and compete for prizes. This guide will cover the steps required for developing a research question and testable hypothesis. Once this year’s fair concludes, encourage your students to search for information about the winners and other projects that might pique the students’ interests.

In a supplemental activity that draws from Science News, Science News for Students and previous educator guides, students can design an experiment to investigate what makes an ideal sugar cookie.

April 28 & May 12, 2018 Fight Like an Animal

What’s in this Guide?

Article-based observation: Questions focus on several different strategies and natural weapons that animals use to fight rival animals of the same species.

Quest through the archives: Use this short section to explore and compare other articles about animal weaponry as reported by Science News since 1924.

Cross-curricular discussion:

Experimental Design questions focus on understanding experimental variables. The graph of rhinoceros beetle body size and horn length is used as an example for defining variables from a related study.

Biological Sciences questions address the early steps of planning a science research project through the exploration of an animal weaponry study.

Engineering questions focus on generating bioinspired engineering research project ideas related to animal weapons.

Please use the following link to access the activity: Cookieology: Experimental Design 101

Purpose: To learn and practice the initial steps of designing a science research project.

Procedural overview: Design a scientific experiment to create the ideal sugar cookie. If time and resources allow, run the experiment, collect and analyze data, and report your results.

Approximate class time: One class period, or more if students will be conducting their experiments.

April 28 & May 12, 2018 Fight Like an Animal

Standards

Next Generation Science Common Core ELA From Molecules to Organisms: Reading Informational Text (RI): 1, 2, 4, Structures and Processes: HS-LS1-1, HS- 5, 7 LS1-2 Ecosystems: Interactions, Energy, and Writing (W): 1, 2, 3, 4, 6, 7, 8, 9 Dynamics: HS-LS2-8 Heredity: Inheritance and Variation of Speaking and Listening (SL): 1, 2, 4, 5, 6 Traits: HS-LS3-1, HS-LS3-2, HS-LS3-3 Biology Evolution: Unity and Diversity: Reading for Literacy in Science and HS-LS4-1, HS-LS4-2, HS-LS4-3, HS-LS4- Technical Subjects (RST): 1, 2, 3, 4, 5, 7, 4, HS-LS4-5 8, 9 Engineering Design: HS-ETS1-1, HS- Writing Literacy in History/Social ETS1-2, HS-ETS1-3 Studies and Science and Technical Subjects (WHST): 1, 2, 4, 7, 8, 9

April 28 & May 12, 2018 Fight Like an Animal

Article-Based Observation: Q&A

Directions: These questions are based on the article “Fight like an animal.” Due to the length of the feature article, students can read the introduction and then divide into five groups to concentrate on one section of the article. The sections are: (1) “Deadliest matches,” focused on nematodes (Steinernema longicaudum), (2) “Territorial female slayers,” focused on fig wasps (Pegoscapus sp.), (3) “Walk away,” focused on sea anemones (Actinia equina), (4) “Worth the fight?” focused on Caribbean mantis shrimp (Neogonodactylus bredini) and (5) “Paradoxically peaceful,” focused on Asian rhinoceros beetles (Trypoxylus dichotomus). Each group should answer questions as they relate to the group’s specific animal. Groups should then report their findings to the rest of the class. After the presentation is complete, show the related video embedded in the article, “How to fight like an animal.”

1. What animal did your group study?

Possible student response: Nematodes, fig wasps, sea anemones, Caribbean mantis shrimp or Asian rhinoceros beetles.

2. What exactly was your animal competing for?

Possible student response: A mate, a food supply, resource-rich real estate or some combination of those.

3. What weapon did your animal evolve to help it compete?

Possible student response: Nematodes have squeezing muscles and sharp spicules. Female fig wasps have jaws capable of decapitating competitors. Anemones have inflatable toxin-injecting stingers. Caribbean mantis shrimp have clublike arms. Male Asian rhinoceros beetles have long horns.

4. What offensive strategy did your animal employ with that weapon?

Possible student response: Nematodes squeeze rivals to death. Fig wasps decapitate rivals. Anemones inject rivals with a tissue-damaging toxin. Caribbean mantis shrimp pound on the shell of a rival with a club that can accelerate as fast as a bullet shooting out of a .22 caliber pistol. And male Asian rhinoceros beetles use their horns to flick rival males away from female beetles.

5. What counterstrategy do other animals belonging to that species use when confronted by a rival?

Possible student response: Rival nematodes could squeeze or avoid their challengers. Rival fig wasps could attempt to decapitate their challengers. Rival anemones could engage in the battle or “walk away” from a challenger. Rival Caribbean mantis shrimp could outnumber the pounds of a competitor. Rival Asian rhinoceros beetles could stealthily find a way around opponents.

6. What human weapons are similar to the weapon of your animal? Possible student response: Similar to nematodes: constricting nets or steel traps. Similar to fig wasps: axes or guillotines. Similar to anemones: poison darts. Similar to Caribbean mantis shrimp: fists, clubs, bombs and artillery. Similar to Asian rhinoceros beetles: canes, pry bars, cattle prods and lances.

7. Does your animal tend to kill its rivals or merely send it away?

Possible student response: Nematodes and fig wasps tend to kill. Anemones, Caribbean mantis shrimp and Asian rhinoceros beetles tend to send their opponents away.

8. What factors determine whether an animal will kill its rivals or send it away?

Possible student response: What makes animals fight to death or simply stop fighting in the middle of a battle is still a question for scientists. Some animals, such as anemones, can’t hurt their rival without also harming themselves, so fighting to a rival’s death may also cause serious self-harm. Other animals, such as mantis shrimp, seem to know when they are outmatched in a battle, and will simply stop fighting at a certain point. On the other hand, once a female fig wasp has found her soon-to-be fig, she’ll fight to kill other female arrivals who try to share her fig’s resources. Female fig wasps have evolved lethal weapons (powerful jaws) for this purpose.

9. What questions do you still have after reading the article?

Possible student response: What other interesting animal weapons and competition strategies exist? Is it inherent in human nature to be similarly competitive with other humans over limited resources, or can we work together peacefully and productively? What new weapons could be genetically engineered into animals? How could human-made weapons and competition strategies be designed or improved based on weapons and strategies used by nonhuman animals?

10. After discussing with your classmates the species featured in “Fight like and animal,” which animal would you choose to be in an intraspecies battle? Explain.

Possible student response: I would be a Caribbean mantis shrimp because the battle against my rival wouldn’t be lethal. Also, administering my defenses likely would not weaken my chances of survival. Deploying my weapon wouldn’t physically harm my body structure. I would have an extraordinary weapon to use on my prey.

April 28 & May 12, 2018 Fight Like an Animal

Article-Based Observation: Q

Directions: These questions are based on the article “Fight like an animal.” Due to the length of the feature article, read the introduction and then divide into five groups to concentrate on one section of the article. The sections are: (1) “Deadliest matches,” focused on nematodes (Steinernema longicaudum), (2) “Territorial female slayers,” focused on fig wasps (Pegoscapus sp.), (3) “Walk away,” focused on sea anemones (Actinia equina), (4) “Worth the fight?” focused on Caribbean mantis shrimp (Neogonodactylus bredini) and (5) “Paradoxically peaceful,” focused on Asian rhinoceros beetles (Trypoxylus dichotomus). Each group should answer questions as they relate to the group’s specific animal. Groups should then report their findings to the rest of the class.

1. What animal did your group study?

2. What exactly was your animal competing for?

3. What weapon did your animal evolve to help it compete?

4. What offensive strategy did your animal employ with that weapon?

5. What counterstrategy do other animals belonging to that species use when confronted by a rival?

6. What human weapons are similar to the weapon of your animal?

7. Does your animal tend to kill its rivals or merely send it away?

8. What factors determine whether an animal will kill its rivals or send it away?

9. What questions do you still have after reading the article?

10. After discussing with your classmates the species featured in “Fight like an animal,” which animal would you choose to be in an intraspecies battle? Explain.

April 28 & May 12, 2018 Fight Like an Animal

Quest Through the Archives: Q&A

1. Find and summarize an article about another animal with weaponry that the animal might use on rivals of the same species.

Possible student response: The Science News article “Hummingbirds take stab at rivals with dagger- tipped bills,” published 11/3/2014, explores how some male hummingbirds may use their beaks as a weapon. Scientists showed that male hummingbirds grow sharp points on their bills, which not only boosts the birds’ piercing power, but also may be used to fend off rivals for mates. Other scientists argue that male and female hummingbirds of this species could have different beak shapes because males and females feed from different types of flowers.

2. Search for and summarize an article about reproductive weaponry in plants.

Possible student response: The Science News article “Milkweed ‘horns’ may equal wins in reproduction battle,” published 3/20/2014, describes how some plants have developed weapons to improve their chances of reproduction. One plant’s pollen or pollen sacs are picked up by insects, birds or other animals and spread to other plants of the same species to fertilize the plants. South American milkweed has evolved large pointed hornlike structures on its pollen sacs. The hornlike structures prevent the pollen sacs of a plant’s neighbor from hitching a ride. This type of “weaponry” could improve the odds that a plant will successfully spread its pollen and discourage the spread of pollen from rival plants.

3. Find and summarize an article about an extinct animal that may have had a weapon.

Possible student response: The Science News article “Saber-toothed salmon teeth more like tusks than fangs,” published 1/7/2016, describes an extinct species of salmon. Fossils from central Oregon that are at least 5 million years old suggest that the teeth of this species stuck out from the side of the face, somewhat like warthog tusks. Scientists speculate that the teeth could have been used as weapons and to shape nests for spawning.

April 28 & May 12, 2018 Fight Like an Animal

Quest Through the Archives: Q

Directions: After reading the article “Fight like an animal,” log in to your Science News in High Schools account and use the Search page to answer these questions. Make sure you adjust the filters to include articles written before 1999, if the question requires you to do so.

1. Find and summarize an article about another animal with weaponry that the animal might use on rivals of the same species.

2. Search for and summarize an article about reproductive weaponry in plants.

3. Find and summarize an article about an extinct animal that may have had a weapon.

April 28 & May 12, 2018 Fight Like an Animal

Cross-Curricular Discussion: Q&A

Directions: After students have had a chance to review the article “Fight like an animal,” lead a classroom discussion based on the questions that follow. These questions are intended to illustrate some of the steps in planning, carrying out and analyzing scientific experiments.

EXPERIMENTAL DESIGN

Discussion questions:

1. What are variables in an experiment?

Variables are factors, traits or conditions that can change in the course of an experiment. Variables can be qualitative (descriptive, like appearance or odor) or quantitative (measurable, like mass or length). Variables can also be continuous (any possible value, like position along a ruler) or discrete (only certain allowed values, such as the number of animals in a cage).

2. What are independent, dependent and confounding variables in an experiment?

An independent variable is a variable that changes during a scientific experiment but that is not changed by the other variables that are being measured. It is controlled by the scientist. The independent variable is often plotted on the horizontal (x) axis of a graph. Note: The independent variable doesn’t always change.

A dependent variable is a variable that changes during a scientific experiment based on other factors in the experiment. A researcher does not control it. For example, a test score is a dependent variable. It depends on how much someone studied, how difficult the test is and even how much sleep a student got the night before. The dependent variable is often plotted on the vertical (y) axis of a graph.

Confounding variables are factors other than the independent variable that may also affect the dependent variable. A good experiment should have one dependent variable and one or maybe two independent variables with value ranges that are methodically tested in the experiment. Confounding variables should be minimized by the experimental design, and any remaining confounding factors should be accounted for when the results are analyzed.

Extension prompts:

3. In the “Beetle body size and horn length” graph in the article “Fight like an animal,” what are the independent, dependent and possible confounding variables? What relationships among the variables does the graph show?

The independent variables are thorax width and beetle sex. The dependent variable is horn length. Possible confounding variables that are not addressed might be beetle age, health, presence of male competitors, presence of females and temperature. The graph shows that horn length is very short and relatively constant for females regardless of thorax width. The graph also shows that for males, horn length increases approximately linearly with thorax width (or more precisely, approximately linearly with any increase in thorax width beyond about 1½ centimeters or so.)

BIOLOGICAL SCIENCES

Discussion questions:

1. Look up an original study for an animal mentioned in “Fight like an animal” and read that study’s abstract (citations are listed at the bottom of the online version of the Science News story). What are the independent and dependent variables, and what is the hypothesis for the relationship between those variables?

Example student responses:

Exaggerated rostra as weapons and the competitive assessment strategy of male giraffe weevils. Dependent variable: contest duration. Independent variable: body length difference. Hypothesis: Contests are shorter when the two competing males have very different sizes, since the larger one quickly wins.

Male-male lethal combat in the quasi-gregarious parasitoid Anastatus disparis (Hymenoptera: Eupelmideae). Dependent variable: fighting intensity. Independent variables: competitor density, female presence. Hypothesis: Fighting intensity increases with increasing competitor density and/or increasing female presence.

2. If you were to do a science research project on animal weapons, what species would you choose to study?

Nematodes, fig wasps, anemones, Caribbean rock mantis shrimp, Asian rhinoceros beetles, etc.

3. What central question about that species’s weaponry would you investigate?

• How is aggressive behavior affected by the density of animals within an environment or by other factors? • How are male-male competitive behaviors and female-female competitive behaviors for [species] similar or different? How common is competitive behavior, instead of cooperative or sexual behavior, between members of the opposite sex for [species]? • Are there multiple uses for [weapon] in [species]?

Extension prompts:

4. What is your hypothesis (the answer you expect to find)? What are your independent and dependent variables?

Higher density of animals (independent variable) promotes more aggressive behavior (dependent variable). One sex (independent variable) is more competitive (dependent variable) than the other, depending on the species. Some weapons (independent variable) are dual-use (dependent variable), useful for fighting rivals but also helpful for mating or acquiring food.

5. What experiments could you conduct to investigate that question and hypothesis?

Putting animal populations into environments with different densities and measuring aggressive behavior. Testing same-sex aggression for both genders under various conditions. Determining weapon use when rivals are present and when they are not.

6. What supplies and requirements would you need to conduct your experiments?

• A considerable number of animals. An appropriate habitat. Suitable food. Student safety and animal welfare approvals if needed. • Handbooks for caring for and studying that species (and telling male from female). • One or multiple video cameras to record animal behavior. • Computer and software to store and analyze recordings and other data. • Rulers and balances for measuring animal size and mass. • Thermometer to measure habitat temperature; perhaps even equipment to maintain a constant habitat temperature. • Nontoxic paint or another way to mark animals to identify them. • Compartments or barriers to separate animals or to control the size of their habitats. • Method to sedate animals (anesthetic, cold, smoke). • Humane method to kill animals if necessary. • Tools to dissect animals. • Dissecting microscope.

7. What measurements would you need to make?

Weapon length or mass from a live or dead animal. Volume or useful surface area of animal habitat. Habitat temperature. Number of animals within a habitat. Number of aggressive actions over a given time as recorded on video. Mating success as recorded on video (or confirmed by genetic testing if resources are available). Weapon use under various conditions as recorded on video.

8. How could you minimize errors in your experiments?

Make sure all instruments (balance, thermometer) are properly calibrated and used. Conduct multiple trials with the same animal. Conduct multiple trials with other animals of the same species. Make measurements several times over the course of the experiment. Watch out for other variables that might be affecting the results (temperature, humidity, light, time of day, amount of food, noise, vibration and other animals in a nearby habitat).

9. How could you graph your results?

Plot (independent variable) density of animals per habitat volume or area on x-axis and (dependent variable) number of aggressive events per hour on y-axis. Plot number of behavioral events per hour over the course of each day. Use bar graphs to compare results for different animals. Use pie charts to quantify animals’ reproductive success by showing the number of offspring that each individual animal produced. Include error bars wherever appropriate.

ENGINEERING Discussion questions:

1. What engineering projects could you do based on animal weapons?

• How can [human weapon or tool] be improved based on the performance of [animal weapon]? • How can [human material or tool] be improved based on the performance of [animal armor]? • How much [force/pressure/etc.] can [animal weapon] produce? • How much [force/pressure/etc.] can [animal armor] withstand? • How can [animal] be genetically engineered to improve their weapon or give them new weapons?

2. What supplies would you need to conduct your experiments?

• Methods of applying consistent force (springs, rubber bands, motors, levers, etc.). • Methods of measuring force or pressure (depth of impression left in a deformable material, spring scale, piezoelectric force sensors, air or water pressure gauges, etc.). • Methods of evaluating weapon efficiency (measure length, mass, angles, shape, density, hardness, etc.). • Methods of evaluating armor efficiency (measure thickness, density, hardness, etc.). • Video camera and computer to record experimental trials and play back in slow motion if necessary. • Software to analyze genes involved in natural weapons and propose modified or new genes that could improve the weapons in an animal.

Extension prompts:

3. What practical applications might result from your project?

Improving the performance of human-designed weapons or tools. Improving the strength per weight, reducing the cost or improving how recyclable certain human materials are.

April 28 & May 12, 2018 Fight Like an Animal

Cross-Curricular Discussion: Q

Directions: The following list of discussion questions is provided to help you take notes, brainstorm ideas and test your thinking in order to be more actively engaged in class discussions related to this article. All questions in this section are related to topics covered in “Fight like an animal.”

EXPERIMENTAL DESIGN

Discussion questions:

1. What are variables in an experiment?

2. What are independent, dependent and confounding variables in an experiment?

Extension prompts:

BIOLOGICAL SCIENCES

Discussion questions:

1. Look up an original study for an animal mentioned in “Fight like an animal” and read that study’s abstract (citations are listed at the bottom of the online version of the Science News story.) What are the independent and dependent variables, and what is the hypothesis for the relationship between those variables?

2. If you were to do a science research project on animal weapons, what species would you choose to study?

3. What central question about that species’s weaponry would you investigate?

Extension prompts:

4. What is your hypothesis (the answer you expect to find)? What are your independent and dependent variables?

5. What experiments could you conduct to investigate that question and hypothesis?

6. What supplies and requirements would you need to conduct your experiments?

7. What measurements would you need to make?

8. How could you minimize errors in your experiments?

9. How could you graph your results?

ENGINEERING

Discussion questions:

1. What engineering projects could you do based on animal weapons?

2. What supplies would you need to conduct your experiments?

Extension prompts:

3. What practical applications might result from your project?

April 28 & May 12, 2018 Fight Like an Animal

Other Related Articles

Science News:

“It’s a bad idea for a toad to swallow a bombardier beetle”

“The way poison frogs keep from poisoning themselves is complicated”

“Animal goo inspires better glue”

Science News for Students:

“Eureka! Lab: To understand a scientific paper, delve into its parts” Readability score: 7.3

“How these poison frogs avoid poisoning themselves” Readability score: 8.3

“Why onions make us cry” Readability score: 7.5

Marie C. Fields/Shutterstock Guide Supplement Cookieology: Experimental Design 101

Guide Supplement Cookieology: Experimental Design 101

What’s in this Guide?

To explore the steps of experimental design, you will plan an experiment to make an ideal sugar cookie. This lab activity is developed from a number of resources including the Science News for Students Eureka Lab! series, “Bake your way to your next science project!,” the 2017 Research in Brief Educator Guide as well as a lesson plan developed by a Science News in High School educator and “tested” with her own research classes. This activity is designed to walk you through the initial steps of designing and conducting an experiment.

This experimental design–focused activity is inspired by the Intel International Science and Engineering Fair — the world’s largest international pre-college science competition that brings together approximately 1,800 high school students from more than 75 countries. During Intel ISEF, held this year in Pittsburgh, from May 13 to May 18, students showcase their independent research and compete for prizes. This guide will cover the steps required for developing a research question and testable hypothesis. Once this year’s fair concludes, encourage your students to search for information about the winners and other projects that might pique the students’ interests.

Guide Supplement Cookieology: Experimental Design 101

Standards

Next Generation Science Common Core ELA Matter and its Interactions: HS-PS1-3, Writing Literacy in History/Social HS-PS1-5 Studies and Science and Technical Subjects (WHST): 1, 2, 4, 7, 8, 9 Energy: HS-PS3-2 Writing (W): 1, 2, 3, 4, 6, 7, 8, 9

Engineering Design: HS-ETS1-1, HS- Speaking and Listening (SL): 1, 2, 4, 5, 6 ETS1-2, HS-ETS1-3 Reading for Literacy in Science and Technical Subjects (RST): 1, 2, 3, 4, 5, 7, 8, 9

Guide Supplement Cookieology: Experimental Design 101

Activity Guide for Teachers

Purpose: To learn and practice the initial steps of designing a scientific research project.

Procedural overview: Design a scientific experiment to create the ideal sugar cookie. If time and resources allow, run the experiment, collect and analyze data, and report your results.

Approximate class time: One class period, or more if students will be conducting their experiments.

Supplies:

• Computers to access the online Cookieology activity • Access to the internet • Cookie supplies o Black+Decker 4-slice toaster oven or other oven at school o Parchment paper o Oven thermometer o Kitchen scale that measures in grams o Toothpicks o Ruler o Oven mitt o Spatula o Premade sugar cookie dough or the ingredients and a general recipe

Direction for teachers: This activity is designed to be a fun way to introduce and allow students to explore experimental design. You can easily alter this activity to make it appropriate for any science class type and level, and you can tailor it to the resources that are available to you and your students. Students probably won’t be thrilled if they aren’t allowed any class time to complete their experiment, but if you don’t have the time or resources at school, then you can encourage them to complete their experiment at home while carefully documenting their work and the resulting data.

Use the Science News for Students “Cookie Science” post titled, “Bake your way to your next science project!” to customize the Cookieology experience for your class. There are a total of 18 posts on designing an experiment to see if a gluten-free cookie can hold its own when compared with a flour- based cookie. The articles cover everything from the experimental design, testing, data collection, results, statistics, research, background knowledge and how to summarize and display your results for the cookie question at hand.

Directions for students:

Have you ever wondered why baking cookies smell good? Or why cookies taste good, especially when they are slightly crispy? What exactly happens in the oven to turn dough into a cookie? Does it surprise you to hear that baking a cookie is actually one big science experiment and that each recipe is essentially an experimental procedure? To explore the steps of experimental design, you will plan an experiment to make an ideal sugar cookie. This lab activity is developed from a number of resources including the Science News for Students Eureka Lab! series, “Bake your way to your next science project!,” the 2017 Research in Brief Educator Guide as well as a lesson plan developed by a Science News in High School educator and “tested” with her own research classes. This activity is designed to walk you through the initial steps of designing and conducting an experiment.

I. Determine an initial focus and conduct background research.

In the future, to start your own research project, you would need to find a topic that interests you. Science research project ideas should come from you, not a parent, teacher, research mentor or someone else. There are many ways to find good project ideas. You might explore the real science that is related to something in a science fiction film or story. You might have ideas for an engineering solution to a real- world problem encountered by you or a family member or friend. You might propose a scientific analysis or engineering application based on one of your hobbies or interests, such as bicycling, sewing or filmmaking. You might think of new questions or applications after learning about new science research in Science News and Science News for Students articles. Log in to Science News in High Schools and search the most recent articles or just look through the current issue of Science News. In the student activity section of the Research in Brief Educator Guide, you could answer the related “Generating Interesting Topics and Questions” prompts to help you form ideas.

In order to proceed with designing your ideal sugar cookie, you probably need to shore up your food science and baking 101 knowledge. In this section, spend some time getting to know the ingredients and science behind the cookie baking process.

For more information on conducting background research, see: Cookie Science 12: Heading to the library. Cookie Science 13: The deal with gluten.

Here are a few resources to get things started and to refer to along the way:

Science News for Students, “Eureka! Lab: Bake your way to you next science project!”

TED-Ed, “The chemistry of cookies – Stephanie Warren.”

ACS Reactions Video “How to Cookie with Science”

1. After watching one of the listed cookie science videos, do you have any initial thoughts about possible questions you would like to test? List three potential questions below.

Does the amount of leavening agent, or raising agent, used affect the height and width of the cookie? Can a sugar cookie be made with too much sugar? Should you add salt to a cookie, and, if so, what is the optimal amount?

2. Do you have a favorite sugar cookie recipe memorized? If not, you’re going to need to do a little research to find a basic recipe that provides a good starting point for your design. Or, if you love the ready-made sugar cookies, then look up the ingredients and cooking instructions for a common type. Print out the recipe or write it below.

Example of a general sugar cookie ingredient list: 1½ cups white sugar, 1 cup softened butter, 1 egg, 1 teaspoon vanilla, 2¾ cups flour, ½ teaspoon baking powder (chemical leavening agent), 1 teaspoon baking soda (chemical leavening agent) and ½ teaspoon salt.

Cooking directions will vary.

3. Assuming you would be using scientific, metric-based lab equipment, do English to metric conversions for each ingredient. (Liquid measurements should be converted to milliliters and solid measurements should be converted to grams.)

Student answers will vary based on the recipe chosen.

4. What are the chemical components of each ingredient? Which ingredients are pure substances or mixtures? Explain your answer and give the chemical makeup of the ingredients — include the chemical formula of ingredients, when appropriate. What role does each ingredient play in cookie composition?

Sugar: Common table sugar, or sucrose, is a pure substance known for its sweet taste. Sucrose is a disaccharide composed of two chemically bonded monosaccharaides, glucose and fructose. When sucrose is heated to approximately 310° Fahrenheit, the Maillard reaction will occur. In this reaction, the carbonyl group of the sugar reacts with the amino group of the amino acid present to produce the signature brown, toasted color and a nutty taste. When sucrose is heated to approximately 350° F, a caramelization reaction will occur — this is when heat breaks down sucrose in the presence of oxygen into the smaller molecules associated with a caramel flavor and other nutty aromas.

Flour: Flour is a mixture. It contains carbohydrates, or starch granules, and proteins such as glutenin and gliadin. Whole wheat flour also contains small pieces of other parts of grain. When water is added to flour, the proteins that were tightly coiled uncoil and link together to form a gluten network. The more you mix the wet flour, the stronger the gluten network becomes. If the gluten network is too strong, gas produced in the baked good will not expand properly. If the gluten network isn’t strong enough to stay risen, the baked good will collapse even if enough gas was produced during the baking process. Flour provides the framework for the general structure of a baked good.

Butter or shortening: Butter is a mixture of fat and water, while shortening is a mixture of only various types of fats, such as vegetable oils. Fats, or triglycerides, create a hydrophobic coating on flour proteins and are used to prevent portions of the gluten network from forming during baking. Slowing gluten formation results in a softer, tenderer cookie.

Egg: Eggs are considered mixtures because they contain many different chemicals and have distinct parts — the yolk and albumen, commonly known as egg white. Eggs help give baked goods a solid structure. When heated to approximately 145° F, the proteins in eggs unwind and create a solid structure. When eggs are added to a dough, the egg proteins coagulate and act as a binding ingredient. Egg whites with air whipped into them can also act as a leavening agent if folded into batter carefully so air does not escape.

Chemical leavening agent: Chemical leavening agents can be mixtures or pure substances. Leavening agents produce gas during the baking process and are therefore used to make batter or dough rise. Baking soda, or sodium bicarbonate (NaHCO3), is a pure, basic substance of only one compound that will react with acids to create carbon dioxide gas. Baking powder is a mixture of NaHCO3 and two acids, typically monocalcium phosphate (Ca(H2PO4)2) and sodium acid pyrophosphate (Na2(H2P2O7)) or sodium aluminum sulfate (NaAl(SO4)2). In baking powder, the base NaHCO3 will not react with the Ca(H2PO4)2 to produce carbon dioxide gas until water is present. The second acid, either Na2(H2P2O7) or NaAl(SO4)2, will not react with NaHCO3 to produce carbon dioxide until the wet dough is warm. The second acid in baking powder prolongs the leavening process so that a new reaction producing carbon dioxide gas begins when the cookies are in the oven. When water in the dough is heated, the resulting steam can also act as a leavening agent. Egg yolks also have lecithin, which is an emulsifier. Emulsifiers allow hydrophobic fats and hydrophilic water-based liquids in a recipe to combine uniformly.

Table salt: Table salt is mostly NaCl, but may contain other additive ionic compounds, such as potassium iodide (KI) or sodium phosphate (Na3PO4). NaCl alone would be considered a pure substance, but when another ionic compound is added, table salt is considered a mixture. In cookies, table salt helps to round out the flavor profile. (In bread, table salt also helps control the production of carbon dioxide gas by yeast, by drawing the water out of yeast.)

5. Name a few chemical reactions and physical changes that occur when ingredients are mixed together and baked.

Chemical reactions: Maillard reaction, caramelization reaction, formation of a gluten network and all leavening acid-base reactions that produce carbon dioxide gas.

Physical changes: fat coating flour proteins, emulsification using egg yolks and production of steam from water.

6. Drawing on what you have learned from your research of the related scientific concepts, look back at your original questions and modify them or ask a new question that could be answered through observation or experimentation.

Does the amount of baking powder used affect the height of the sugar cookies? Which leavening agent works best? Which type of fat makes the softest sugar cookie?

7. Describe the results you expect to observe.

The more baking powder used, the thicker the cookie will be. Baking soda will be the best leavening ingredient because it will allow carbon dioxide to be produced throughout the baking process. Shortening will produce a thicker cookie than butter, because it does not contain any water.

II. Define your variables and develop your own testable Cookieology hypothesis from your proposed question.

After all that research and brainstorming, it’s your turn to determine how to scientifically address your cookie question. You’ll need to plan out an experiment by first developing a hypothesis that you want to test. Your hypothesis should be testable and should identify variables that can be measured or qualified throughout the experiment. You can collect quantitative data (data that consists of numbers, such as temperature, width or mass) and/or qualitative data (data that consists of nonnumeric characteristics as perceived by a human, such as texture or color).

1. What quantitative cookie data might you want to collect to address your cookie question, and how would you collect it? Duration that cookies were in the oven (with a timer); actual oven temperature (with one or more oven thermometers); internal cookie temperature (with a cooking thermometer); ingredient masses or cookie total mass (with a scale); cookie width or thickness (with a ruler); cookie softness (using a press to measure the force exerted and a ruler to measure the change in cookie thickness) and pH of the ingredients or cookie (with quantitative colorimetric pH paper).

2. What qualitative cookie data might you collect to address your cookie question, and how would you collect it?

Cookie color (photographed and compared with a chart of colors by the experimenter or by volunteers), texture (judged on a relative scale by taste-tester volunteers or evaluated by the experimenter with photographs, or with a magnifier or a low-power microscope) and taste (judged on a relative scale by taste-tester volunteers).

Now that you have determined what data you can collect, establish your experimental variables and eliminate unwanted ones. A variable is a factor, trait, object or condition whose value can change in the course of an experiment. As you saw from above, a variable can be qualitative (descriptive) or quantitative (measurable). A quantitative variable can be continuous or discrete. Cookie height, for example, is continuous because it can be any number between its minimum and maximum value. The number of heads or tails in coin tosses, though, is discrete because you would only use whole numbers to describe the data.

The independent variable is a factor that you, the experimenter, manipulate in order to observe its relationship to a phenomenon that can be measured (the dependent variable). Think “I” for “independent” and the one that “I” can control. Think “D” for “dependent” and for “data generated.” Experiments are designed to find out how the independent variable affects the dependent variable.

3. Identify one factor or variable that you will manipulate — the independent variable.

The amount of baking powder.

4. Identify one factor or variable that you will measure — the dependent variable.

The height and width of the resulting sugar cookie.

Now, create a testable hypothesis: Your hypothesis will need to be tested to generate one or more lines of evidence that will either support or refute it. A good hypothesis should be original and testable. Think through an experiment that can be done and that is repeatable. Write a hypothesis that defines a relationship between your variables. You may want to narrow down your research problem to a statement that is directional. A non-directional hypothesis defines that a relationship exists between two variables in some way. A directional hypothesis not only defines the relationship between variables, but also predicts a positive or negative change or difference between the two variables.

For examples, see Cookie Science 2: Baking a testable hypothesis.

5. Write a non-directional hypothesis that defines relationships between your variables.

The amount of baking powder will affect the height and width of the resulting sugar cookie.

6. Write a directional version of the above hypothesis. As the amount of baking powder added increases, the height of the resulting cookie will increase and the width will decrease.

III. Think about how you would analyze and display the data you collect, and the potential errors that will need to be controlled for by the procedure.

For additional information, see: Cookie Science 5: ‘Blinding’ your subjects.

1. How will you plan to analyze your data? Will you run any mathematical tests to see if there is statistical significance among your data, either proving or disproving your hypothesis? If so, make sure you determine the population size that you need to run the specific statistical test. Your teacher will give you more guidance for this question.

Student answers will vary based on class level. Teachers should adjust the question so that it is suitable for their class.

2. Some errors in data collection are random. Random errors can be either positive or negative fluctuations that affect the accuracy of your data. The best way to minimize random error is to test as many identical samples as possible, then take the average of those results. What sorts of random errors might occur in the cookie project?

Random errors could occur because of temperature fluctuations during baking and differences in the masses of each cookie.

3. Other errors in data collection are systemic. They always occur in the same direction; all of the measurements are off in the same way. Systemic errors affect the accuracy of the data. What sorts of systemic errors might occur in the cookie project?

The oven temperature might be consistently higher (or lower) than the set temperature. The weigh scale might not be calibrated, in which case it would always overestimate (or always underestimate) the dough mass of each cookie.

After analyzing the data, charts and graphs can be used to illustrate relationships between variables, or what your data found. Consider the following charts and graphs, and think about which one will most accurately represent the findings of your cookie experiment.

4. Pie charts show each component’s relation to the whole. The categories are represented as slices of the pie and are usually shown in different colors. What cookie data might you graph using pie charts?

Proportions of ingredients in cookies (by mass or by volume) or fractions of taste-tester volunteers who gave various responses about the cookies.

5. Bar graphs compare values between two or more populations, with the height of each bar representing the value for that population. Sometimes single bars are divided into segments of different colors to illustrate the relative contributions of different factors to that group. What cookie data might you graph using bar graphs?

Average diameter of the cookie at different conditions or fractions of taste-tester volunteers who gave various responses about the cookies. 6. Time-series graphs show measurements over a period of time. Either axis could be used for time, but usually time is plotted on the x-axis (horizontal axis). Data are plotted as dots or small circles. To help visualize the trend in the data, data points are usually connected by straight lines between data points or by a smooth curve of a mathematical function that best explains the trend in the data. What cookie data might you graph using time-series graphs?

The spread of the cookie relative to the time spent in the oven. The softness, temperature or other properties of the cookie relative to the time spent in the oven.

7. Scatterplots show a relationship between two quantitative variables. The independent variable is plotted on the x-axis (horizontal axis) and the dependent variable is plotted on the y-axis (vertical axis). What cookie data might you graph using scatterplots?

The change in height or rise of the cookie (on the y-axis) versus the amount of a certain ingredient added to the recipe (on the x-axis). Cookie softness (on the y-axis) versus the amount of a certain ingredient or the baking time (on the x-axis). Oven temperature (on the y-axis) versus location within the oven (in any one dimension, on the x-axis).

IV. Write and perform your procedure.

If your teacher asks, create a stepwise, detailed procedure for your Cookieology research project. While designing the procedure, make sure you think about ways to minimize potential errors, make accurate measurements and create reproducible results.

For additional information about writing a procedure, see: Cookie Science 6: Baking it up.

Keep in mind that many experiments (even surveys, and certainly things like taste tests) require safety and consent paperwork before the experiments can begin. If you think you might be entering a science fair in the future, check the Society for Science website for all the rules and paperwork before you start any project!

For example, see Cookie Science 4: Cookie ethics.

Be sure to keep a detailed data table in your lab notebook throughout the duration of your project. Write down any relevant ideas you had or experiments that you did each day. Make sure to put the date on each page.

For more details about keeping a good lab notebook, see Cookie Science 3: The lab notebook.

V. Analyze and display your results.

In the final phase of a project, you should analyze your data and draw conclusions. When you analyze your data be sure to estimate your experimental error (the accuracy of your results) and the effects of any assumptions you made during the experiment. Perform other relevant statistical tests with your data to help determine if your hypothesis is true.

For more information on statistics, see: Statistics: Make conclusions cautiously. Cookie Science 8: The meaning of the mean. Cookie Science 9: How data can spread. Cookie Science 10: Finding the cookie difference. Make tables and graphs of your experimental data. For all graphs and charts, it is important to include a title, labels for the axes and appropriate units for the variables. Wherever possible, use different colors to make it easier to identify different important aspects of the data. You should indicate experimental error on your graphs when possible, usually with small bars to show the standard deviation around the mean of each data point or bar height.

For additional information, see: Cookie Science 14: One experiment, 400 cookies. Cookie Science 11: That’s the way the cookie crumbles. Cookie Science 15: Results aren’t always sweet. Cookie Science 17: Posters – the good and the bad.

You should always aim to answer a standard set of questions in your results section. Below is a set of general questions that you should be able to answer after your analysis.

1. State your results. Was your hypothesis correct or incorrect? Explain.

Student responses will vary.

2. Did your work lead to a modified hypothesis or to a new hypothesis that appears more likely to be correct?

Student responses will vary.

3. What conclusions did you draw from your cookie experiments?

Student responses will vary.

Researchers often state what future work they might do if they continue that same project, or what they wish they had done differently during the experiment.

For example, see: Cookie Science 16: If I had to do it all again.

4. What didn’t go as planned in your experiment? How did these errors affect your results? What would you do in the future to minimize unwanted errors?

Student responses will vary.

5. What additional experiments might you conduct, or in what additional directions might you go, if you were to continue your cookie research project?

Student responses will vary.

Guide Supplement Cookieology: Experimental Design 101

Activity Guide for Students

Purpose: To learn and practice the initial steps of designing a scientific research project.

Procedural overview: Design a scientific experiment to create the ideal sugar cookie. If time and resources allow, run the experiment, collect and analyze data, and report your results.

Approximate class time: One class period, or more if students will be conducting their experiments.

Supplies:

Directions for students:

I. Determine an initial focus and conduct background research.

The first step in the scientific experimental design process is to find a good topic in order to formulate a suitable research question and hypothesis. Since this activity defines the scope of the “research field,” you might not need to do additional searching to find a research topic at this time. In the future, to start your own research project, you would need to find a topic that interests you. Science research project ideas should come from you, not a parent, teacher, research mentor or someone else. There are many ways to find good project ideas. You might explore the real science that is related to something in a science fiction film or story. You might have ideas for an engineering solution to a real- world problem encountered by you or a family member or friend. You might propose a scientific analysis or engineering application based on one of your hobbies or interests, such as bicycling, sewing or filmmaking. You might think of new questions or applications after learning about new science research in Science News and Science News for Students articles. Log in to Science News in High Schools and search the most recent articles or just look through the current issue of Science News. In the student activity section of the Research in Brief Educator Guide, you could answer the related “Generating Interesting Topics and Questions” prompts to help you form ideas.

For more information on conducting background research, see: Cookie Science 12: Heading to the library. Cookie Science 13: The deal with gluten.

Here are a few resources to get things started and to refer to along the way:

Science News for Students, “Eureka! Lab: Bake your way to you next science project!”

TED-Ed, “The chemistry of cookies – Stephanie Warren.”

ACS Reactions Video “How to Cookie with Science”

1. After watching one of the listed cookie science videos, do you have any initial thoughts about possible questions you would like to test? List three potential questions below.

5. Name a few chemical reactions and physical changes that occur when ingredients are mixed together and baked.

7. Describe the results you expect to observe.

II. Define your variables and develop your own testable Cookieology hypothesis from your proposed question.

1. What quantitative cookie data might you want to collect to address your cookie question, and how would you collect it?

2. What qualitative cookie data might you collect to address your cookie question, and how would you collect it?

3. Identify one factor or variable that you will manipulate — the independent variable.

4. Identify one factor or variable that you will measure — the dependent variable.

For examples, see Cookie Science 2: Baking a testable hypothesis.

5. Write a non-directional hypothesis that defines relationships between your variables.

6. Write a directional version of the above hypothesis.

III. Think about how you would analyze and display the data you collect, and the potential errors that will need to be controlled for by the procedure.

For additional information, see: Cookie Science 5: ‘Blinding’ your subjects.

6. Time-series graphs show measurements over a period of time. Either axis could be used for time, but usually time is plotted on the x-axis (horizontal axis). Data are plotted as dots or small circles. To help visualize the trend in the data, data points are usually connected by straight lines between data points or by a smooth curve of a mathematical function that best explains the trend in the data. What cookie data might you graph using time-series graphs?

IV. Write and perform your procedure.

For additional information about writing a procedure, see: Cookie Science 6: Baking it up.

For example, see Cookie Science 4: Cookie ethics.

For more details about keeping a good lab notebook, see Cookie Science 3: The lab notebook.

V. Analyze and display your results.

Make tables and graphs of your experimental data. For all graphs and charts, it is important to include a title, labels for the axes and appropriate units for the variables. Wherever possible, use different colors to make it easier to identify different important aspects of the data. You should indicate experimental error on your graphs when possible, usually with small bars to show the standard deviation around the mean of each data point or bar height.