MODULE: NATURE OF SCIENCE
USF STARS PROGRAM
FALL 2003
MODULE: Nature Of Science
Extended Background
Benchmark: SC.H.1.2
SC.H.2.2
SC.H.3.2
Importance of Science and Technology on Society
Increasing levels of CO2 in the atmosphere caused by the steady decline of tropical rain forests and the steady rise in industrial pollution has created worldwide concern over the future of the planet Earth. A space station is in the process of being built to be used to study the Earth, stars and man in space… and boiling a pot of water.
What do these three things have in common? They are all directly linked to the wonderful thing called science.
Science permeates our lives and informs our actions. Physics, for example, teaches us how mirrors work, how glasses can aid one's vision and how heat is treated by various household materials (plates and utensils). Chemistry discusses the principles of matter, like atoms, molecules and compounds. It discusses the countless different substances that can arise from the minutest variations within compounds. These atoms, molecules and compounds make up the water we drink, the food we eat, the air we breathe, the medicines we take when we are sick. Some we can't possibly live without. Biology, the study of life, teaches us why we are the way we are, why we need what we need to survive, how all living things are categorized, when we all came from. These, and countless other questions and answers are all related to science. In order to keep our economy growing, we need a new wave of educated students ready for modern scientific research, teaching, and technological development.
There have been so many tremendous advances in technology over the last decade or so, in fact the pace is accelerating. Everyday new things are discovered and with the increase in scientific knowledge, there is an increase in demand for educated students. Cancer research has found a virus capable of killing cancerous tumors in rats. Although this has not been sufficiently tested for use on people yet, scientists predict that testing on human volunteers may come into effect in around two years or so. There have also been the ever-controversial breakthroughs in the cloning of sheep and mice, which can have a great impact (whether good or bad) on the future.
Furthermore, it is essential for Americans to know how well students are doing in science because without this knowledge you can't even hope to be able to modify the school systems with the intention of challenging and encouraging students in the various branches of science. To accommodate growing reliance on this subject, you can't leave everything the way it is and hope that American students keep on top.
Similarly, science is also important in the international job market. The greater the advances in scientific technology, the greater the demand for workers sufficiently educated in these particular areas. Excellence in the sciences can open many doors, otherwise closed, for students. These skills can get you a job almost anywhere in the world, and with the growing concerns about finding jobs, it certainly helps to have so many options available to you. From engineering to dentistry, or from cancer research to maintaining a national park, a large percentage of the jobs today require background in science.
There is another important aspect of science that is often forgotten. Science is fun many ways. Learning is always fun but it's especially rewarding when it has something to do with the things going on around you. There is a satisfaction that comes from learning about these often complex matters that goes far beyond merely getting a good grade. It helps you to understand the world around you and to appreciate its complexities. It teaches you that we can't possibly understand everything about the world ever, but we go on trying anyway, engaging in the never- ending search for truths... and why? We do this because science is fun and exciting. The more we learn, the more we feel ourselves pushed towards the answers and towards further questions, towards the future.
The Scientific Method
There are a series of steps, called the scientific method, to help experimenters systematically investigate observations that can be tested with the experimental method. The scientific method is the process by which scientists, collectively and over time, endeavor to construct an accurate representation of the world. The scientific method is used to minimize the influence of our perceptions and beliefs in the explanation of natural phenomena. It provides a set of rules to guide the experimentation process. The scientific method consists of the following main different steps:
Observations
The first step in the scientific method is to carefully observe something in the world that creates curiosity about why things work the way they seem to work. The experimenter should write down in very clear terms exactly what is being observed and why it creates such curiosity. Also, begin thinking about possible variables that might affect the problem and gather information to see if other scientists have attempted a solution to the problem.
Hypothesis
A hypothesis is a question that has been reworded into a form that can be tested experimentally. In essence, it is the predicted outcomes. The experimenter should attempt to predict how any experiments will turn out and what the answer to the question(s) might be. While there is often a logical reason for making these predictions, this step may be largely intuitive and may reflect past experience with similar questions.
Hypotheses are possible causes, not just a generalization based on inductive reasoning. There is usually a separate hypothesis for each major question being asked and probably one overall hypothesis for the entire project. A hypothesis should be testable. One or more experiments should be planned for testing each hypothesis. It is not necessary that the hypothesis end up being correct; many are not. Hypotheses can be proven wrong or incorrect, but they can never be proven with absolute certainty. It's quite possible that in the future someone with additional knowledge may find an example where the hypothesis is not true.
Methods of Testing
The next step is to examine the different ways to test the validity of each of the hypothesis. If possible, an experiment should be designed to test each hypothesis.
The experimenter should write down an experimental procedure in terms of a step-by-step listing of what is needed in order to answer each of the questions raised. For an experiment to yield answers that can be trusted, there must be a "control", an additional test or trial run done exactly the same as the others except that no variables are changed. The control experiment becomes a reference point that allows the experimenter to see what would have happened if nothing was done, and compare it to what did happen when a variable was altered. Controls are sometimes difficult to design, but they are a very important part of the scientific method. The experimenter should write down predicted results of each specific test. This will help thinking about the experiments in detail and plan for what elements to be watching for when doing the testing.
The methods selected should be such that others can repeat the experimentation and that all who do the experiments will have a result that is measurable (quantifiable). Experiments are often done numerous times to assure that the observations and conclusions are reproducible. Reproducibility is crucial; without it no proof can be established that results are accurate. Reproducible experiments reduce the chance that the testing was performed incorrectly.
Experimentation
The experimenter should conduct the experiment several times if necessary and carefully record the results obtained. Instead of making general statements about the results of the experiments, the experimenter should gather and record actual, quantitative data from them. Data can be the amount of force applied, the chemicals used, an object's physical measurements, the time something took, etc.
All observations should be carefully recorded. If the results obtained were expected, then the experiment supports the hypothesis. The experimenter should keep an accurate record of how the experiments were conducted so others can replicate it.
Results
The experimenter should carefully examine the results, double check calculations and look for patterns or surprises. The experimenter should keep an open mind in order to analyze the data and interpret the results accurately, not to prove the hypothesis was right. If results are unexpected, the experiment could be repeated to confirm that the methods used were correct and measurements were accurate.
The experimenter should plot any graphs and draw tables of the results. The study of tables and graphs helps see trends to determine how different variables may have caused an impact on the response variable (the observation). Conclusions about the experiments should be reached based on those trends.
Conclusions
The experimenter should examine the results and state whether the predictions were confirmed or not. The experimenter should answer the original questions using the trends in the experimental data and observations to determine whether or not the hypothesis was correct. If the hypothesis was correct, the major factors that prove the hypothesis should be briefly explained. If the hypothesis was in error, the experimenter should try to explain the results and possible answers to the original questions and/or hypothesis. The experimenter should keep in mind that many major scientific breakthroughs have occurred because a scientist did not get the results expected and went back to do more experimentation to find out an explanation.
MODULE: Nature Of Science
Activity: “Color Burst”
Benchmark: SC.H.1.2
SC.H.2.2
SC.H.3.2
Lesson Background
This lesson uses a technique called paper chromatography. The water is absorbed by the coffee filter and rises up the filter. When the water reaches a spot of black ink, it carries the components of the spot up the filter. As the water continues to rise, the components do not all travel with it at the same rate. Some are more soluble in water than others, and the more soluble ones travel faster. After a time, the various components are at different distances from the original spot, having been separated from one another. Substances in which other substances dissolve, like water, are called solvents. Scientists use chromatography frequently to separate and identify the component parts of a mixture.
This activity will help children gain experience in conducting simple investigations of their own while working in small groups. Throughout the lesson, encourage children to observe more and more carefully, measure things carefully, record data clearly in logs and journals, and communicate their results in charts and simple graphs as well as in prose. Student investigations should be followed up with presentations to the entire class to emphasize the importance of clear communication in science.
Introductory Statement:
To gain experience in asking questions and conducting inquiry by exploring the separation of colors in water and other solvents; to communicate and share findings of student investigations.
Science Skills
Observation
Analyzing
Sketching
Critical thinking
Materials
§ 2 colorless plastic or glass cups
§ Blue, yellow, and green food coloring
§ 1, 8-ounce wide-mouth plastic cup filled with a half inch (1 cm) of water
§ Coffee filters (#6 size) or similar size
§ Black water-soluble marker (nonpermanent markers for overheads work best)
§ 2-3 paper towels
Engaging Questions
This part should be done as a teacher demonstration.
1. Fill two colorless plastic or glass cups about 3/4 full of water.
2. To one of these add a few drops of blue food coloring and to the other a few drops of yellow. Mix well. (The colors should be pretty deep for a good effect.)
3. Pour about 1/3 of each colored solution into another empty cup. Mix well.
- Ask students to describe what is observed. (The new color (green) seems to be a mixture of blue and yellow.)
- To a fourth cup of water, add a few drops of green food coloring
Ask students:
§ Can you tell the difference between the color in this fourth container from that in the third?
§ Is the green food coloring a mixture of blue and yellow?
§ How can we find out?
Try to guide the students to think about how to separate a combination of dyes into its individual components in order to figure out what the combination is.
How to manage experiment
Each person or small group will need these materials:
§ 1, 8-ounce wide-mouth plastic cup filled with a half inch (1 cm) of water
§ Coffee filters (#6 size) or similar size
§ Black water-soluble marker (nonpermanent markers for overheads work best)
§ 2-3 paper towels
The supplies should be separated and ready for use prior to the class because preparing them during the lesson may disconnect the continuity of the thought process after the initial demonstration.
Teacher’s Procedure
1. Using the black marker, have students decorate both sides of the coffee filter with a few dots, lines, or other markings. The simpler the pattern, the more striking the results will be. Caution students to be careful not to mark the ribbed bottom edge.