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Nature of Science

Performance Benchmark N.12.A.4
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Nature of Science
Scientific Inquiry


Science, Technology, and Society
Content Areas
Nature of Science (NOS)
Life Science
Earth Science
Physical Science

Students know how to safely conduct an original investigation using appropriate tools and technology. E/L

Since the National Science Education Standards were published in 1996, there has been a tremendous push to promote using the inquiry process in the science classroom. One part of inquiry is to have students participate in scientific investigations using authentic tools and technology. These investigations can range from traditional laboratory-based experiments to engineering-style design activities. While such science investigations can provide students with a deep understanding of science and a rich experience, they may also present many hazards commonly found in a laboratory environment. Therefore, students must keep safety as their number one priority when performing scientific investigations to ensure successful learning.

Figure 1. The Occupational Safety and Health Administration produces a large number of safety posters appropriate for the science classroom. (from


Safety begins with the classroom teacher setting up a safe learning and working environment. Materials and equipment must be used, maintained, and stored in accordance with appropriate safety rules and guidelines; the local school district should have these available for all teachers. These rules and guidelines are based on laboratory safety requirements promulgated by the Occupational Safety and Health Administration and the Nevada Division of Industrial Relations. Also, organizations such as the Laboratory Safety Institute post general guidelines for setting up a safe area.

For more information about guidelines to setting up a safe science laboratory, go to

The laboratory must have safety equipment appropriate for the scientific investigations that are conducted. At a minimum, all laboratory areas should have a fire extinguisher, fire blanket, and first aid kit. A laboratory where chemicals are used also needs an eye wash, body shower, fume hood, and spill neutralization kit.  

Figure 2. Safety equipment for a laboratory where chemicals are used. (from


The area must be large enough to prevent overcrowding and ensure that students have the space to perform experiments safely. The amount of available room per student varies depending on whether the space is mixed use (classroom/laboratory), where more overall space is needed to safely conduct investigations, or stand-alone laboratory, where less overall space is needed to safely conduct investigations.

The National Science Teachers Association has published a discussion of school laboratory space considerations. This discussion can be found at
The teacher should provide a safety overview at the beginning of the school year and students should be aware that they share responsibility for a safe environment in their science classroom. Having the students and their parents sign a safety contract is an excellent way to reinforce the serious nature of safety in the classroom. Many districts require these contracts be signed by both students and their parents and returned prior to students participating in any laboratory activities. In a classroom where scientific investigations are conducted many times during the year, having the contract signed and returned in the first two weeks of school is essential.  

A good safety contract template is found at

It is important to note that the teacher should make the safety contract as specific to their classroom environment as possible; generic safety contracts lack meaning and relevance, thereby, discouraging active thought about safety issues.

Emergency procedures should be discussed at the beginning of the school year. At a minimum, procedures should be in place to handle first aid for cuts, burns, chemical contact to eyes and skin, electric shock, and animal bites. Along with first aid, emergency procedures should be established in case of fires, chemical spills, and general evacuations.

Figure 3. A first aid kit is essential for every science laboratory and the procedures for proper use should be understood by students. For a list of critical policies and procedures, go to


If chemicals are used in the laboratory, Material Safety Data Sheets (MSDS) should be posted or kept in a clearly marked binder. Students should be made aware of the location of the sheets and how to use them in case of an emergency.

To get MSDS for chemicals commonly used in school laboratories, go to

Student should also understand and practice using safety gear such as protective eyewear, aprons, and gloves. Be aware that some students may have latex allergies and may need to use hypoallergenic gloves. Teachers can instill the use of safety gear by consistently wearing safety gear during classroom demonstrations, laboratory experiments, or any time scientific investigations are being conducted.

The teacher should constantly reinforce safety throughout the year with their students. Before every laboratory activity, safe use of equipment and materials in the lab need to be considered and documented. For many teachers, this means detailing the procedures for the laboratory, modeling the use of the equipment and materials, and using pre-laboratory safety quizzes. This is certainly an effective technique at the beginning of the school year and/or when new laboratory equipment and materials are introduced. However, later in the year, to deepen student understanding of experimental design, including development of proper safety procedures, the teacher may want the students to create their own laboratory safety procedures before conducting their investigations. This moves the scientific investigation from being completely teacher-centered to more student-centered.

When students develop their own laboratory procedures, they should include those that concern laboratory safety. It is critical that the teacher check and approve these procedures prior to experimentation. Likewise, if students are allowed to expand their original scientific investigations beyond the scope of the original procedures, any modifications should be discussed with and approved by the instructor prior to conducting further experiments.

To learn more about how scientific investigations are critical to effective instruction, including the need to develop a safe laboratory environment, go to

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Performance Benchmark N.12.A.4

Students know how to safely conduct an original investigation using appropriate tools and technology. E/L

Common misconceptions associated with this benchmark

1. Students incorrectly use too much of a chemical when conducting an investigation.
Many accidents involving chemicals are a result of too much of that chemical being used. Before proceeding with a scientific investigation that involves chemicals, teachers and students should ensure they are using the minimum amount of the chemical allowed by the experiment. Many investigations can be successfully conducted with only small amounts of chemicals and very dilute solutions. Teachers and students also should consider using the safest chemical possible to perform an experiment. The least hazardous and toxic material should be used in all cases.

To learn more about this common laboratory mistake, as well as proper procedures for a chemistry laboratory, see

2. Students may not complete all the procedures in a scientific investigation, resulting in unsafe conditions.
Many unsafe conditions can result if some of the laboratory procedures are not completed. It is important that the teacher monitor students not only to make sure they are following the approved procedures, but also that they complete every step. For example, students may be conducting a force and motion experiment involving springs. If the procedures are not completed, the spring mechanism may be in its maximum energy position, and if this mechanism is released accidentally, injury could result. To prevent incomplete investigations, a general checklist can be used by the students and teachers to ensure that all procedures have been completed.

To learn more about the different laboratory safety checklists, go to


3. Students incorrectly think that conducting scientific investigations is inherently unsafe.
Many students have preconceived notions that scientists commonly engage in unsafe practices. Students commonly view scientists as “mad” eccentrics that consider only the acquisition of knowledge and do not care who or what they hurt in the process. Perhaps this stereotype comes from literature and the modern media, where these mad scientists (often white males, wild haired, and in a lab coat) are performing dangerous experiments that potentially can destroy the whole world. However, teachers should develop “student scientists” in their classroom, and as students develop scientific investigations that are safe, they come to understand that this is the norm in scientific activity.

More information about the “mad scientist myth” can be found at

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Performance Benchmark N.12.A.4

Students know how to safely conduct an original investigation using appropriate tools and technology. E/L

Sample Test Questions

1st Item Specification: Explain the use of proper experimental controls and control groups in experimental designs.

Depth of Knowledge Level 1

  1. Experimental controls are used in scientific investigations to
    1. prevent multiple data sets that will interfere with the testing of the hypothesis.
    2. lower costs of performing multiple trials to insure accuracy and precision.
    3. assist in maintaining accurate records that reflect the true data collected.
    4. allow for the graphing of one set of independent and dependent variable data.
  1. Control groups are useful in scientific experiments because they
    1. are easily identified by the experimenter during the investigation.
    2. are cheap and relatively easy to maintain throughout the experiment.
    3. prevent the data collection from being contaminated by other variables.
    4. provide a standard for comparison with the data collected in the investigation.

Depth of Knowledge Level 2

  1. A scientist sets up an investigation to study the effect of temperature on bacterial growth. She plans to count the bacterial growth each day as she changes the pH slightly, places the petri dishes with the bacteria in the refrigerator and in an incubator, and varies the type of agar that she uses. What observation can you make about her experiment?
    1. Her design will effectively measure temperature changes on bacteria growth.
    2. She has too many variables that will affect understanding the temperature changes on bacterial growth.
    3. Different types of agar and pH changes will not prevent understanding the effect of temperature on bacterial growth.
    4. All her variables are controlled within the design of the experimental investigation.
  1. A researcher wants to study whether a new soft drink will be popular with consumers due to its taste. He wants to have a test group taste the soft drink in comparison to other popular brands on the market. Which research design would be an acceptable method for the researcher and controls variables?
    1. Have multiple soft drinks available. Each participant tastes most of them and selects his favorite.
    2. Have each participant view the types of soft drinks and taste all of them selecting the best flavor.
    3. Participants taste the new soft drink and one other drink rinsing their mouth with water after each test recording their favorite beverage.
    4. Each participant tastes the new soft drink compared to other soft drinks keeping a score card of what beverage they liked best.

2nd Item Specification: Explain the components of a scientific investigation.

Depth of Knowledge Level 1

  1. Scientific investigations include
    1. having a testable hypothesis.
    2. testing multiple variables at one time.
    3. using several control groups.
    4. having undefined data sets.
  1. Scientific investigations include all of the following EXCEPT
    1. having an appropriate control group.
    2. identifying a testable hypothesis.
    3. testing one variable at a time.
    4. having multiple unrelated data sets.

Depth of Knowledge Level 2

  1. A student is designing a science fair project to test the relationship between the rate of a chemical reaction and different factors such as changing the temperature, pH and size of the reactant materials. He decides to test the hypothesis: Rate of reaction increases when the temperature of the reaction is increased. In his experimental design, he heats his reaction and increases the acidity of the solution. Which of the following is correct?
    1. He is testing two variables at the same time.
    2. He has a correct hypothesis in relation to the experimental design.
    3. The experimental design could be improved by grinding the reactants.
    4. He has identified his control for the investigation.

3rd Item Specification: Describe proper and appropriate use of lab equipment.

Depth of Knowledge Level 1

  1. In order to light a Bunsen burner, a student should do the following:
    1. turn on the gas, light the match, place the match flame in two inches above the burner.
    2. turn on the gas, light the match and adjust the burner controls.
    3. adjust the burner controls, turn on the gas then light the match.
    4. light the match, turn on the gas, touch the match to the tip of the burner, adjust the controls.
  1. When measuring liquids, always
    1. select small graduated cylinders for large quantities of liquid.
    2. pour small quantities into large graduated cylinders.
    3. select the graduated cylinder that best measures the quantity you need.
    4. pour directly from the container into your laboratory without measuring it.

Depth of Knowledge Level 2

  1. A student is conducting an experiment using a Bunsen burner when the fire bell rings. What should he do?
    1. Exit the room and quickly exit the building following directions from hall monitors.
    2. Turn the gas off, exit the room and quickly leave the building.
    3. Leave his eye goggles on, exit the room and quickly leave the building.
    4. Turn the gas off, pour the reaction down the sink, exit the room and quickly leave the building.
  1. A student is conducting an experiment that requires her to pass a test tube through a flame in order to heat the contents of the test tube evenly. Which piece of equipment is most appropriate for this activity?
    1. Test tube holder because it adjusts to the size of the test tube.
    2. Test tube rack because it is made of wood.
    3. Crucible tongs because they are very small.
    4. Buret clamp because it can be secured to the ring stand.

4th Item Specification: Explain safety considerations in lab procedures.

Depth of Knowledge Level 1

  1. When instructed by your teacher, the proper way to smell a chemical is to
    1. put the container next to your nose and inhale.
    2. waft the smell away from your nose.
    3. waft the smell towards your face.
    4. have your lab partner smell the chemical.
  1. When handling an acid that accidently spills on your hand, you should
    1. wipe your hands on your lab apron.
    2. start rinsing your hand under the faucet.
    3. put a base on your hand to neutralize the acid.
    4. use  a paper towel to wipe the acid off your hand.

Depth of Knowledge Level 2

  1. A student is conducting a laboratory investigation and needs to obtain chemicals for his lab station. He should do all of the following EXCEPT
    1. know the names and formulas of the chemicals needed for the investigation.
    2. know the quantities of all the chemicals needed for the activity.
    3. take all the chemicals to his desk and measure what he needs.
    4. carry only what he can safely manage to his desk and then obtain the remaining materials.
  1. Which of the following is the BEST procedure before doing any laboratory investigation?
    1. Clean up the lab station and gather all the materials.
    2. Read and make a list of all the materials needed for the activity, note all the safety issues.
    3. Ask your partner to read through the laboratory and write out the directions.
    4. Wait for your teacher to tell what materials you will need when the laboratory is ready to begin.

5th Item Specification: Explain how inquiry drives the processes of science.

Depth of Knowledge Level 1

  1. Which of the following is not part of scientific inquiry?
    1. Analyzing data.
    2. Collaborating with peers.
    3. Doing a verification lab.
    4. Testing a scientific question.
  1. All of the following are important components of scientific inquiry EXCEPT
    1. explaining new results in terms of current scientific knowledge.
    2. using evidence to support scientific concepts and understandings.
    3. presenting scientific findings to scientific community and peers.
    4. learning a new laboratory technique for separation of mixtures.

Depth of Knowledge Level 2

  1. Why is it important to explain new findings in terms of current scientific knowledge?
    1. New findings can help us to understand or revise current theories and concepts.
    2. New findings can help scientists promote their careers and obtain grants.
    3. Current scientific knowledge cannot be revisited or changed.
    4. Scientific knowledge is the same as scientific laws and not subject to change.
  1. Collaboration among scientists is an important component of scientific inquiry for all of the following EXCEPT
    1. scientists can learn from each other by sharing ideas and findings.
    2. scientists tend to argue during collaboration and fail to generate new ideas.
    3. new procedures for problem solving can develop through collaboration.
    4. experimental data can be validated by replicating each other’s work.

6th Item Specification: Analyze an experimental design.

Depth of Knowledge Level 1

  1. Your neighbor asks you to review her child’s science fair project design. The student wants to test the hypothesis that green plants need sunlight to grow. She plans to grow one plant on her patio and the other plant in the closet. Which of the following would you suggest?
    1. Be sure to leave the plant in the sun, then place the same plant in the closet.
    2. Be sure to control variables such as water, fertilizer and temperature.
    3. Use shade tolerant plants for the closet and sun tolerant plants for the patio.
    4. Use distilled water mixed with Miracle Grow fertilizer for both sets of plants.
  1. You and your lab partner need to design an experiment to test for the effect of acids on metals. You decide to use one type of acid and control the concentration but test different metals such as copper, aluminum, iron and tin. Your lab partner wants to use several different types of acids. Which of the following is your BEST response to her?
    1. There is not enough time during the class period to test different types of acids and their effects on metals.
    2. Different types of acids are more difficult to obtain and too much time would be spent trying to find them.
    3. The experiment needs to be controlled and testing several acids on different metals is too many variables.
    4. Collecting the data from her design requires setting up several data charts which is more difficult to analyze.

Depth of Knowledge Level 2

  1. A student wants to test Mendel’s hypothesis that crossing a tall pea plant with a short pea plant will produce only tall pea plants. He obtains pea plant seeds from the nursery and grows them. Which of the following is the most correct statement about his experimental design?
    1. He does not know what the genotypes of his plant seeds are.
    2. The plants may be infertile and unable to produce flowers.
    3. The phenotypes are easy to identify after they fully mature.
    4. The plants are identical in genotype and phenotype.
  1. A student finds an unlabeled bottle of white substance left at his desk and wants to identify it. His teacher says that it is either sodium chloride or glucose because these two substances were used in the last class. Which of the following procedures would be the most appropriate way to test for the nature of the substance?
    1. Dissolve it in distilled water. Perform a conductivity test. If it conducts then it is a salt. Sugars do not conduct electricity.  
    2. Dissolve it in water, then taste the water to see if it is salty or sweet. Glucose tastes sweet and can be identified.
    3. Use a magnet to see if one of the substances is attracted to the magnetic field.
    4. Use equal amounts of each of the substances dissolved in water and calculate their densities.

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Performance Benchmark N.12.A.4

Students know how to safely conduct an original investigation using appropriate tools and technology. E/L

Answers to Sample Test Questions

  1. A, DOK Level 1
  2. D, DOK Level 1
  3. B, DOK Level 2
  4. D, DOK Level 2
  5. A, DOK Level 1
  6. D, DOK Level 1
  7. A, DOK Level 2
  8. D, DOK Level 1
  9. C, DOK Level 1
  10. B, DOK Level 2
  11. A, DOK Level 2
  12. C, DOK Level 1
  13. B, DOK Level 1
  14. C, DOK Level 2
  15. B, DOK Level 2
  16. C, DOK Level 1
  17. D, DOK Level 1
  18. A, DOK Level 2
  19. B, DOK Level 2
  20. B, DOK Level 1
  21. C, DOK Level 1
  22. A, DOK Level 2
  23. D, DOK Level 2

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Performance Benchmark N.12.A.4

Students know how to safely conduct an original investigation using appropriate tools and technology. E/L

Intervention Strategies and Resources

The following list of intervention strategies and resources will facilitate student understanding of this benchmark.

1. Dr. Cal’s Guide to Laboratory Safety

The University of Illinois, Chicago has developed a comprehensive website concerning primarily chemistry laboratory safety. The site includes an overview, as well as how students can prepare laboratory procedures that keep safety first.

To visit Dr Cal’s safety site, go to


2. Start the School Year Safely! Article

This article by Ron Hammond is published at the website and includes a nice checklist of items to do at the beginning of the year to ensure a successful and safe year of laboratory science. The article discusses general housekeeping, planning for safety, a safety inventory, and safety contracts.

To access the article, go to


3. Using Safer Chemicals Article

The American Chemical Society has published an article about using safer chemicals for common chemical reactions that are used in school laboratories. The article includes an activity that can be conducted at the beginning of the year that demonstrates effective, safer chemicals for laboratory use, and ultimately, how these chemicals will reduce the risk of potential accidents.

The article and activity can be found at
ACS/ ACSContent/education/greenchem/SafeStart.pdf


4. Safety Resources

Flinn Scientific, Inc., has created a comprehensive laboratory safety site for schools. The site includes (1) Material Safety Data Sheets (MSDS) for many common chemicals used at schools, (2) articles concerning laboratory safety, (3) specific demonstrations and articles concerning eye and eyewear safety, (4) a list of general laboratory safety issues that help the teacher create a safe environment, (5) some sample safety contracts and exams, (6) safety resources outside of Flinn, and (7) a way to subscribe to Safety Notes, Flinn’s free service that provides monthly training videos on safety.

Flinn’s site can be accessed at


5. On-line Safety Tutorial

For those schools that have access to Internet computers, may wish to have their students conduct the Biology Lab Safety Tutorial produced by Baruch College. The tutorial is for biology students, but many of the topics covered in the tutorial relate to general laboratory safety. Additionally, the site contains quizzes where students can gauge their safety understanding for each section.

The safety tutorial is located at

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