Americans' Factual Knowledge of ScienceUnderstanding nanotechnology, probability and experiments

Feb 2, 2010Dominic Lusinchi

Forty-seven percent of Americans have heard of nanotechnology and 63 percent of them identified the correct definition of that field of scientific inquiry.

The 2008 National Science Board (NSB) survey asked respondents who had some familiarity with nanotechnology (inderdisciplinaryscience.suite101.com/article.cfm/nano), to assess whether a statement on the differing properties of the same materials at different scale levels were true or not - 41% provided the right answer. Only one-third of these respondents answered both questions correctly.

However, this should not be surprising, since nanotechnology is a relatively recent field of study - the term was first defined in the 1970s and it is only in 2000 that the U.S. National Nanotechnology Initiative was created. It takes times for innovations to enter the public consciousness.

These results and more (see also americanaffairs.suite101.com/article.cfm/scientific-literacy-and-the-public) are contained in the NSB's Science and Engineering Indicators 2010 ( a biennial study on the state of science and technology in the U.S.

Understanding Probability

The survey also posed questions about the "scientific process", specifically assessing respondents’ knowledge of probability and experimental design among things. For instance, they were asked: "A doctor tells a couple that their genetic makeup means that they've got one in four chances of having a child with an inherited illness. (1) Does this mean that if the first child has the illness, the next three will not have the illness? or (2) Does this mean that each of the couple's children will have the same risk of suffering from the illness?"

Nearly two-thirds (65%) answered both questions correctly: 82 percent answered the first question correctly and 73 percent got the second right. No major changes have occurred since 1988, i.e. about the same proportion of respondents answer correctly.

This genetic inheritance question is similar to that of tossing a fair coin, except that the "coin" here does not have a 50/50 chance, it has a 25% chance of coming up Heads (illness) and a 75% chance of coming up Tails (no illness). The parents' genetic makeup does not change after a child is born, so the risk to the next child remains the same (25/75) as that of the previous born. All siblings have the same risk.

Understanding Science Experiments

The experimental design question asked: "Two scientists want to know if a certain drug is effective against high blood pressure. The first scientist wants to give the drug to 1,000 people with high blood pressure and see how many of them experience lower blood pressure levels. The second scientist wants to give the drug to 500 people with high blood pressure and not give the drug to another 500 people with high blood pressure, and see how many in both groups experience lower blood pressure levels. (1) Which is the better way to test this drug? (2) Why is it better to test the drug this way?"

In 1995, 26 percent of respondents gave the correct answer, now (2008) it is 38 percent, although it has gone up as high as 46% (2004).

Thus it appears that some improvement has occurred in this area. Not a day goes by without a daily newspaper reporting the results of a clinical trial - which uses the set up adopted by the second scientist. How well it is reported is always an issue: after all, this is how the public is informed about these matters - people rely on some sort of information outlet (newspapers, the Web, TV).

The standard experimental procedure is to create two groups; each study participant is assigned to one of them through some kind of chance (random, i.e. unbiased) process, like flipping a coin. One groups receives the experimental drug, the other does not (scientificinquiry.suite101.com/article.cfm/scientific_method_uses_experiments_and_controls). Then, when the results are in, a reliable determination regarding the effectiveness of the drug can be made. On this issue, women performed better than men, although the difference is small: 39 percent v. 37 percent, respectively.

Source:

National Science Board. 2010. Science and Engineering Indicators 2010, Chapter 7 “Science and Technology: Public Attitudes and Understanding”. Arlington, VA: National Science Foundation (NSB 10-01).
Questions

What is the main idea of this article?

What can you take from this article to help you with your culminating assignment experimental design?

Does Mouthwash Kill Bacteria? Data AnalysisClass Experiment to Examine Effect of MouthWash on Oral Microbes

Nov 4, 2008Tami Port

After completing a classroom experiment in which students take oral samples to see if mouthwash reduces the number and variety of bacteria, this is how data are examined.

This classroom activity is designed to compare effectiveness of different mouthwashes, one containing alcohol (Listerine) and one that does not contain alcohol (Crest), in reducing the populations of oral bacteria. The experimental design also allows for the assessment of rinse time as a factor in mouthwash effectiveness.

After oral samples are obtained and incubated for 24 hours, the class then examines the number of bacterial colonies and the variety of different types of bacterial colonies growing on the surface of the agar. A colony is made up of millions of bacteria that are visible as dots on the surface of agar in a Petri dish.

What Are Dependent and Independent Variables?

Most experiments are designed to establish a cause and effect relationship between two variables. The independent variable is the factor whose effect is tested in the experiment. Its magnitude is purposely varied or manipulated by the experimenter. The dependent variable is the factor measured by the investigator. Its magnitude depends on the independent variable. In order to effectively measure the effect of the independent variable on the dependent variable, all other variables must be held constant for the duration of the experiment. These variables are referred to as controlled variables.

Mouthwash Experiment Variables, Questions and Hypotheses

After collecting the oral samples, there are several questions that the students should answer to ensure that they understand the scientific method of this experiment. For a complete description of the experimental setup see the article Does Mouthwash Kill Bacteria? Data Collection.

Experimental Variables

What Is Being Manipulated? There are really two questions being investigated in this experiment; two independent variables that are manipulated. What are they?

What Will Be Measured? When the plates are examined after incubation, the class will be comparing the different sections of the plate as well as different types of mouthwash. What are these are the dependent variables.

Questions and Hypotheses

What Scientific Questions Are Being Asked Though This Experiment? Hint: One question relates to each of the independent variables.

What Are the Hypotheses? The students need to make two hypotheses, each based on one of the scientific questions being asked. A hypothesis is a prediction, an educated guess of what the results will bear. It is not necessary for all students to have same hypothesis.

Recording Results of Mouthwash Experiment

After incubation of the plates for at least 24 hours, the class will compare the number of bacteria colonies in each section, and the variety (number of different types of colonies that do not look the same). Students will compare the differences between their own 3 sections as well as the differences that may result from using different kinds of mouthwash.

Questions

What is the main idea of this article?

What can you take from this article to help you with your culminating assignment experimental design?

It is no easy task to formulate a strong problem question and even professional scientists and researchers struggle with the process.

Component 2: Form a Hypothesis. A hypothesis may be formally defined as the possible explanation of some phenomenon. Realistically, a hypothesis is nothing more than an educated guess (but certainly more than a mere opinion) that the researcher makes as to the answer to the problem question. The hypothesis gives a prediction of the outcome of an experiment, and the analysis determines if the prediction is accurate.

Failure is instructive. The person who really thinks learns quite as muchfrom his failures as from his success.

(John Dewey)

The Experiment is Designed

Component 3: Methods and Materials. This component involves planning and then conducting the actual experiment and would include a step-by-step and highly detailed plan of exactly what would be done in the experiment. Within this plan would be found:

  • details on the specific kinds and amounts of materials and supplies that would be required to conduct the experiment.
  • details on manipulating variables and establishing control and test groups. Many factors or variables influence processes and outcomes. For example, to study the effect of a synthetic hormone on the growth rate of rats, rats would be put into identical cages, given identical amounts of water and food, and placed so they receive identical amounts of light. The cages, water, food, and light are called the independent variables. The synthetic hormone, called the dependent variable, might be dispensed in the rats' food or water. The rats receiving the hormone would be designated as the test group while the rats not receiving the hormone would be designated the control group. If the test group grows larger faster than the control group, then it might be concluded that since the hormone was the only variable that differed between the two groups, the hormone did indeed increase the growth rate of the test rats. Without the control group there is no way to guarantee that the hormone produced an increased growth rate as there would be no group with which to compare results.
  • details on sample size and sampling methods. The rule of thumb on sample size is: the larger the sample, the more accurate the results. Should one be suspicious of a new medicine that was advertised to have miraculous powers but come to find out was only tested on 20 people? 200 people? Yes, highly suspicious.
  • details on what data will be collected and how the data will be organized. In the rat growth rate experiment example, one would carefully weigh the rats in both the test group and the control group over a given period of time and organize the weights obtained into a data table.

Data is Analyzed

Component 4: Analyze the Data. Once scientists collect the raw data from a well-designed experiment what happens to it? How do scientists make heads or tails out of what the numbers (data) may be trying to tell them?

How do Scientists Design Valid Experiments?

Science is Based on Experiments That Yield Reliable Data

Jul 13, 2009Dennis Holley

Modern science was born with the realization that hypotheses must be tested with valid experiments that yield trustworthy data.

Science may be defined as the search for natural truths (facts and information) undertaken by exacting individuals (scientists) using precise and reliable methods. What are these scientific methods? How do scientists design and conduct experiments to get at the truth?

Experiments are a series of components (steps) usually carried out in sequence.

The Problem is Established

Component 1: The Problem. Curiosity leads to questions to be answered and problems to be solved. The first step must be to specify exactly what is to be solved. This is accomplished through the problem question. The problem question should:

  • be stated in clear and concise language.
  • be specific kinds and amounts of materials and supplies that would be required to conduct the experiment.
  • present only one problem to be solved at a time.

A problem well stated is a problem half solved.

(C. F. Kettering)

It is no easy task to formulate a strong problem question and even professional scientists and researchers struggle with the process.

Component 2: Form a Hypothesis. A hypothesis may be formally defined as the possible explanation of some phenomenon. Realistically, a hypothesis is nothing more than an educated guess (but certainly more than a mere opinion) that the researcher makes as to the answer to the problem question. The hypothesis gives a prediction of the outcome of an experiment, and the analysis determines if the prediction is accurate.

Failure is instructive. The person who really thinks learns quite as muchfrom his failures as from his success.

(John Dewey)

The Experiment is Designed

Component 3: Methods and Materials. This component involves planning and then conducting the actual experiment and would include a step-by-step and highly detailed plan of exactly what would be done in the experiment. Within this plan would be found:

  • details on the specific kinds and amounts of materials and supplies that would be required to conduct the experiment.
  • details on manipulating variables and establishing control and test groups. Many factors or variables influence processes and outcomes. For example, to study the effect of a synthetic hormone on the growth rate of rats, rats would be put into identical cages, given identical amounts of water and food, and placed so they receive identical amounts of light. The cages, water, food, and light are called the independent variables. The synthetic hormone, called the dependent variable, might be dispensed in the rats' food or water. The rats receiving the hormone would be designated as the test group while the rats not receiving the hormone would be designated the control group. If the test group grows larger faster than the control group, then it might be concluded that since the hormone was the only variable that differed between the two groups, the hormone did indeed increase the growth rate of the test rats. Without the control group there is no way to guarantee that the hormone produced an increased growth rate as there would be no group with which to compare results.
  • details on sample size and sampling methods. The rule of thumb on sample size is: the larger the sample, the more accurate the results. Should one be suspicious of a new medicine that was advertised to have miraculous powers but come to find out was only tested on 20 people? 200 people? Yes, highly suspicious.
  • details on what data will be collected and how the data will be organized. In the rat growth rate experiment example, one would carefully weigh the rats in both the test group and the control group over a given period of time and organize the weights obtained into a data table.

Data is Analyzed

Component 4: Analyze the Data. Once scientists collect the raw data from a well-designed experiment what happens to it? How do scientists make heads or tails out of what the numbers (data) may be trying to tell them?

One method of analysis is to graph the data. Graphs turn numbers into graphics which is useful because pictures are more easily understood than lists of numbers. Another analysis scientists perform is to run statistical tests on their raw numerical data. Statistical tests are mathematical processes that help determine if the data collected are significant and if so, how significant.

Component 5: Draw a Conclusion. Analysis of the data will hopefully reveal whether the original hypothesis was correct (supported by the data) or incorrect (not supported by the data). That in turn should answer the original problem question. In the conclusion component, scientists attempt to put the results in perspective, establish the significance of the results, and explain how the experiment fits into existing knowledge.

If science is the search for natural truths, then scientists must be very exacting in that search to ensure that truths are what result. Well-designed experiments are the key to the reliability of the entire scientific enterprise.

Questions

What is the main idea of this article?

What can you take from this article to help you with your culminating assignment experimental design?

Understanding Scientific Inquiry

Inquiry Involves the Use of Critical Thinking to Understand Science

Feb 28, 2008David R. Wetzel

Scientific Inquiry involves higher order critical thinking as students learn to ask questions, design experiments, conduct minds-on investigations, and present findings.

Scientific Inquiry and Higher Order Thinking Skills

Scientific inquiry causes students to use higher order thinking skills and learn science from a minds-on approach. Inquiry’s foundation originates with John Dewey. In Dewey’s book Democracy in Education (1916), he indicates that education begins with the curiosity of learners. Student curiosity and involvement in scientific inquiry moves them beyond passive learning to higher order thinking by:

  • asking questions;
  • designing investigations;
  • investigating;
  • formulating explanations;
  • presenting findings;
  • reflecting on findings.

Scientific inquiry causes a fundamental change from traditional teaching practices to a collaborative relationship between teacher and students. In collaborative environments students take risks without fear of ridicule. Teachers become facilitators as they:

  • model scientific inquiry skills;
  • ask guiding questions;
  • allow student creativity.

Scientific Inquiry and Critical Thinking

Scientific inquiry causes confusion as students analyze experimental findings. Confusion is good in this setting, because it demonstrates critical thinking by students is taking place. Critical thinking results in students drawing inferences that display a greater level of understanding (Hinrichsen, J. and Jarrett, D., 1999, Science inquiry in the classroom, 7-10). Northwest Regional Education Laboratory Resources