The Nature of Science

The Nature of Science Do Now: In your notes answer the following question What does science mean to you?

- Science is a way or a process used to investigate what is happening around us. Science - You can use scientific methods to search for new knowledge and to solve everyday problems.

What are some of the skills scientists use to solve problems?

Scientists use both observations and experiments to find answers. • Scientists use prior knowledge and background information. • Sources of Information • Scientific journals and books • Library • Internet • Reliability?

Observation/Inference Observations are what you learn through your senses. An Inference is how you explain what you observe.

Scientists use technology. • What is technology? • Technology is the application of science to make products or tools that people can use to make life easier • Computer • Robotics • Medical Expertise and Equipment

Science and Technology • New discoveries lead to new technology and products. Science continues to challenge old knowledge and ways of doing things. Modern communication assures that scientific information is spread around the world.

Technology in Your Lifetime • List five technologies that you used this morning as you got ready to come to school. • List three technologies that have improved the study of science.

Scientists must share their information. • Published results and conclusions of experiments in magazines and professional journals where other scientists can read to keep up with new information • Journals are used to communicate scientific observations, questions, thoughts, and ideas • Your notebook will be your scientific journal

DO NOW • What are the 5 steps of the scientific method? • Problem • Hypothesis • Test Hypothesis (experiment) • Analyze data • Form conclusion

The Scientific Method • Used to solve all problems. • A step by step process to answer questions. an example is…

Recognize the Problem Form a Hypothesis Test your Hypothesis Plan –Design an Experiment Do – Observe and Record Analyze your Data Draw Conclusions

Recognize the problem “What question needs to be answered?” “What problem needs to be solved?” “What do you want to know?”

Form a hypothesis A Hypothesis is a ‘prediction’ or statement that can be tested. A Hypothesis is an ‘educated guess.’ A Hypothesis is based on information that you already know.

Test your hypothesis (Perform an experiment) In well planned experiments, variables are tested. Only ONE variable changes at a time. • INDEPENDENT VARIABLE • DEPENDENT VARIABLE • CONSTANTS

Independent variable The variable that is changed by the experimenter. When graphing, always put the independent variable on the horizontal axis, called the x-axis.

Dependent variable The variable that is being measured. The variable that changes because of what the experimenter does. When graphing, always put the dependent variable on the vertical axis, called the y-axis.

Constant(s) The variable(s) that stay the same.

Your experiment will not be valid unless a control is used. A CONTROL is a sample that is treated exactly like the other experimental groups except that the independent variable is not applied to it.

To make sure that results of an experiment are valid, you need to conduct several trials of your experiment. The actual number of trials will vary with each experiment, but the more trials completed using the same exact methods, the more reliable the results will be.

Materials selected must match the experiment. Safety must always be a priority. Data tables help to organize observations and test results. Bias, or a particular slant based on individual differences, should be eliminated.

Finally… DO THE EXPERIEMENT! Follow procedure(s) as planned.

Analyze your data Once your experimentation is completed. • Review all observations and measurements. • Organize OBSERVATIONS and DATA. • Look for patterns, trends, correlations, similarities, differences …

DATA Data is information you obtain through measurement and calculation. Quantitative, Objective.

Draw conclusions Must match the objective. Must support the hypothesis. Communicate findings.

Revision if necessary Follow all the same steps and replan.

Do Now (while I check your homework) • List the 5 steps of the scientific method (without notes) A hypothesis is an “If/Then” statement: • What does the “If” part tell you? • What does the “Then” part tell you? • Write a hypothesis about the following question… How does temperature affect tropical plant growth?

DO NOW • Define: • Volume- • Mass- • Describe: How to find the volume of a solid, both regular and irregular.

Ways to organize information for analysis. • Graphing • Data table

Do Now: What is the best way to organize data?One way to analyze data is to arrange it in the form of a Graph…

Graphing • Data can be analyzed to see if it supports the hypothesis. • A graph is a diagram that shows the relationship of one variable to another. • A graph makes interpretation and analysis of data easier.

How to Construct a Line Graph • 1. Independent Variable on the X axis, label with units. • 2. Dependent variable on the y axis, label with units. • 3. Determine the variable range – Subtract the lowest number from the highest. Do this for each variable • 4. Determine the scale of the graph – (by 2, 5, 10 or more) Spread out the graph to use MOST of the paper. Turn the paper so that the variable with the widest range is on the longer side. Count how many boxes you have and then compare to your range from #3 to determine what number to scale by.

Continued • 5. Plot the data points. Plot each point with an “X”. If your point is not exactly on the line of the graph estimate the best spot. • 6. Connect the X’s. Draw a curve that best fits the data points. Do not connect the dots! • 7. Title the graph. If your graph has more than one set of data provide a key to identify different lines.

Give your graph a title… 50 40 30 20 10 PLANT GROWTH OVER TIME G R O W T H (cm) Always put the dependent variable on the vertical axis, called the y-axis. Label and scale each axis, Including units. Plot the data and connect. Graphing example 0 1 2 3 The origin TIME (days) Always put the independent variable on the horizontal axis, called the x-axis. Back

Extrapolate • extending the graph, along the same slope, above or below measured data.

Interpolate • obtaining a value from a graph that is located between major points given, or between • data points plotted.

Another way to analyze data is to arrange it in the form of a Data Table

Data Tables • Identify the independent variable • Label the first column • Record the values • Identify the dependent variable • Label the next column(s) • Record the values

Give your data table a title… Identify the independent variable • Label the first column Identify the dependent variable • Label the next column(s) PLANT GROWTH OVER TIME TIME (days) GROWTH (cm) Record the values Record the values 0 1 2 3 0 32 38 40 Data table example

Experiments with Multiple Trials • Each trial becomes a new column • Must match the procedure • The final column would average them

Number of Successes

Variety of Data Tables • Depend on the type of experiment • Contain the information related to the experiment • Organized format for analyzing data Back

The Nature of Science