Chapter 1, Lesson 1 Notes
*Science is a way of learning about the natural world.
*Science also includes skills all the knowledge gained by exploring the natural world.
*Scientists use skills such as observing, inferring, predicting, classifying, evaluating, and making models to study the world.
*Observing means using one or more of your senses to gather information. It also means using tools to help your senses.
*A quantitative observation deals with numbers, or amounts.
*A qualitative observation deals with descriptions that cannot be expressed in numbers.
*When you explain or interpret the things you observe, you are inferring, or making an inference. Inferring is not guessing. Inferences are based on reasoning from what you already know.
*Predicting means making a statement or claim about what will happen in the future based on past experience or evidence
*predictions and inferences are closely related.
*The difference between a prediction and an inference is that a prediction is a statement about what will happen, and an inference is an attempt to explain what is happening or has happened.
*Classifying is the grouping together of items that are alike in some way.
*Evaluating involves comparing observations and data to reach a conclusion about them.
*Making models involves creating representations of complex objects or processes. Some models can be touched, such as a map. Others are in the form of mathematical equations or computer programs.
*Models help people study things that can’t be observed directly.
*Planning and carrying out an investigation may use many of the scientific skills. It may also involve identifying variables.
*Independent variables are changed to test a hypothesis.
*Dependent variables change in response to the independent variables.
Chapter 1, Lesson 2 Notes
*An attitude is a state of mind.
*Scientists possess certain important attitudes, including curiosity, honesty, creativity, open-mindedness, skepticism, good ethics, and awareness of bias.
*One attitude that drives scientists is curiosity. Scientists want to learn more about the topics they study.
*Good scientists always report their observations and results truthfully. Honesty is especially important when a scientist’s results go against previous ideas or predictions.
*Sometimes it takes creativity to find a solution to a problem. Creativity means coming up with inventive ways to solve problems or produce new things.
*Scientists need to be open-minded, or capable of accepting new and different ideas. However, open-mindedness should always be balanced by skepticism, which is having an attitude of doubt.
*Scientists need a strong sense of ethics, which refers to the rules that enable people to know right from wrong.
*What scientists expect to find can influence, or bias, what they observe and how they interpret observations.
*Personal bias comes from a person’s likes and dislikes.
*Cultural bias stems from the culture in which a person grows up.
*Experimental bias is a mistake in the design of an experiment that makes a particular result more likely.
*Scientific reasoning requires a logical way of thinking based on gathering and evaluating evidence.
*Being objective means that you make decisions and draw conclusions based on available evidence.
*In contrast, being subjective means that personal feelings have entered into a decision or conclusion.
*There are two types of scientific reasoning. Deductive reasoning is a way to explain things by starting with a general idea and then applying the idea to a specific observation.
*Inductive reasoning uses specific observations to make generalizations.
*Scientists must be careful not to use faulty reasoning, because it can lead to faulty conclusions.
Chapter 1, Lesson 3 Notes
*Standard measurement allows scientists everywhere to repeat experiments.
*In the 1970’s, scientists in France developed a system of measurement called the metric system.
*The metric system is a system of measurement based on the number 10.
*Modern scientists use a version of the metric system called the International System of Units, or SI.
*Using SI as the standard system of measurement allows scientists to compare data and communicate with each other about their results.
*In the SI system, the basic unit for measuring length is the meter (m). For lengths smaller than a meter, the centimeter (cm) and millimeter (mm) are used. The kilometer (km) is used for measuring long distances.
*Mass is the amount of matter in an object. A balance is used to measure mass by comparing the mass of an object to a known mass.
*In the SI system, the basic unit for measuring mass is the kilogram (kg). To measure smaller masses, grams (g) and milligrams (mg) are used.
*Unlike mass, weight is a measure of the force of gravity acting on an object. A scale is used to measure weight.
*Volume is the amount of space an object or substance takes up.
*In SI, the basic unit for measuring volume is the cubic meter (m3).
*A cubic meter is equal to the volume of a cube with 1-meter sides. Use cubic meters to measure the volume of solids.
*To measure the volume of a liquid, use the liter (L), and read the level at the bottom of the meniscus, or curve.
*To measure the volume of an irregular solid, use the displacement method: immerse the object in water and measure how much the water level rises.
*Density, a measure of how much mass is contained in a given volume, is expressed as a relationship between two units.
*In SI, the basic unit for measuring density is kilograms per cubic meter (kg/m3)
*In addition to the Celsius scale, scientists sometimes use another temperature scale, called the Kelvin scale. In fact, the Kelvin (K) is the official SI unit for temperature.
*A thermometer is used to measure temperature.
*The second (s) is used to measure time.
Chapter 1, Lesson 4 Notes
*Math skills that scientists use to collect data include estimation, accuracy and precision, and significant figures.
*An estimate is an approximation of a number based on reasonable assumptions. It is not a guess.
*Scientists often rely on estimates when they cannot obtain exact numbers. They may base an estimate on indirect measurements, calculations, and models.
*Accuracy and precision have different meanings. Accuracy refers to how close a measurement is to the true or accepted value. Precision refers to how close a group of measurements are to each other. A reliable measurement is both accurate and precise.
*Significant figures communicate how precise measurements are. The significant figures in a measurement include all digits measured exactly, plus one estimated digit.
*When you add or subtract measurements, your answer can only have as many places after the decimal as the measurement with the fewest places after the decimal.
*When you multiply measurements, the answers should only have the same number of significant figures as the measurement with the fewest significant figures.
*Scientists use certain math tools to analyze data.
*These tools include calculating percent error; finding the mean, median, mode, and range; and checking the reasonableness of data.
*Percent error calculations are a way to determine how accurate an experimental value is. A low percent error means the result you obtained was accurate. A high percent error means your result was not accurate.
*The mean is the numerical average of a set of data. The median is the middle number in a set of data. The mode is the number that appears most often in a list of numbers. The range of a set of data is the difference between the greatest value and the least value in the set.
*An important part of analyzing any set of data is to ask, “Are these data reasonable? Do they make sense?” Data that do not fit with the rest of a data set are anomalous data.
Chapter 1, Lesson 5 Notes
*To help see what data mean you can use a graph. A graph is a “picture” of your data
*One kind of graph is a line graph. Line graphs display data that show how one variable (dependent variable) changes in response to another variable (independent variable)
*Scientists control changes in the independent variable. Then they collect data about how the dependent variable changes.
*A line graph is used when an independent variable is continuous, which means there are other points between the tested ones. You can make a linear graph from a table and draw a line of best fit.
*A line graph in which the data points yield a straight line is a linear graph.
*The kind of graph in which the data points do not fall along a straight line is called a nonlinear graph. Both kinds of graphs are useful.
*Line graphs are powerful tools in science because they allow you to identify trends, make predictions, and recognize anomalous data.
*Graphs make it easy to see anomalous data points. When a graph does not have any clear trends, it probably means that the variables are not related.
Chapter 1, Lesson 6 Notes
*Thinking and questioning is the start of a scientific inquiry process.
*Scientific inquiry refers to the diverse ways in which scientists study the natural world and propose explanations based on the evidence they gather.
*Scientific inquiry often begins with a question about an observation. In trying to answer a question, you are developing a hypothesis. A hypothesis is a possible answer to a scientific question.
*After developing a hypothesis, you are ready to test it by designing an experiment. An experiment must follow sound scientific principles for its results to be valid.
*Variables are factors that can change in an experiment. The one variable that is purposely changed to test a hypothesis is the independent variable. The factor that may change in response to the independent variable is the dependent variable. All other variables must be kept the same.
*An experiment in which only one variable is manipulated at a time is called a controlled experiment. In any experiment, there is a risk of introducing bias.
*Data are facts, figures, and other evidence gathered through qualitative and quantitative observations. After data have been collected, they need to be interpreted. Then you can draw conclusions about your hypothesis. A conclusion is a summary of what you have learned in an experiment.
*Communicating is the sharing of results and ideas with others through writing and speaking. Scientists communicate by giving talks at scientific meetings, exchanging information on the Internet, or publishing articles in scientific journals.
*Experiments are one way of gaining scientific knowledge, but sometimes they are not practical. Observations and modeling are two other ways of gaining scientific knowledge.