The Nature of Science The Methods of Science Scientific Measurements Graphing

The Methods of Science The Scientific Method Chapter 1

The Methods of Science Science studies natural patterns. Science studies natural patterns. Science is classified into three main categories: life science Science is classified into three main categories: life science

Earth science

and physical science and physical science sometimes a scientific study will overlap the categories. sometimes a scientific study will overlap the categories.

The Methods of Science Science explains the natural world; explanations can change over time. Science explains the natural world; explanations can change over time.

Scientists investigate nature by observation, experimentation, or modeling. nature by observation, experimentation, or modeling.

Scientific method Organized set of investigation procedures Organized set of investigation procedures 1) State a problem. 1) State a problem.

2) Gather information

3) Form a hypothesis or educated guess based on knowledge and observation. or educated guess based on knowledge and observation.

Scientific method 4) An experiment with variables is a common way to test a hypothesis. 4) An experiment with variables is a common way to test a hypothesis.

Experimental variables A. A dependent variable changes value as other variables change. A. A dependent variable changes value as other variables change. B. An independent variable is changed to determine how it will affect the dependent variable. B. An independent variable is changed to determine how it will affect the dependent variable.

Scientific method C. A variable that does not change when other variables change is a constant. C. A variable that does not change when other variables change is a constant. D. A control is the standard to which test results can be compared. D. A control is the standard to which test results can be compared.

5) Analyze data from an experiment or investigation. from an experiment or investigation.

Scientific method 6) Form a conclusion based on the data. 6) Form a conclusion based on the data.

7) Reduce bias by keeping accurate records, using measurable data, and repeating the experiment. by keeping accurate records, using measurable data, and repeating the experiment.

Models Represent ideas, events, or objects and can be physical or computerized. Represent ideas, events, or objects and can be physical or computerized.

A theory is an explanation based on many observations and investigations; is an explanation based on many observations and investigations;

A scientific law is a statement about something that always seems to be true. is a statement about something that always seems to be true.

Science deals with the natural world Questions of value or emotion cannot be answered. Questions of value or emotion cannot be answered.

Technology Applied science helping people Applied science helping people

Standard Exact quantity that people agree to use for comparison Exact quantity that people agree to use for comparison

Standards of Measurement Measurements must have a number and a unit. Measurements must have a number and a unit. SI – an improved version of the metric system used and understood by scientists worldwide. SI – an improved version of the metric system used and understood by scientists worldwide.

SI system is based on multiples of 10 and uses prefixes to indicate a specific multiple. is based on multiples of 10 and uses prefixes to indicate a specific multiple.

Length Is measured using a unit appropriate for the distance between two points. Is measured using a unit appropriate for the distance between two points.

Volume The amount of space an object The amount of space an object occupies. occupies.

Mass Measure of matter in an object Measure of matter in an object

Density Mass per unit volume of a material. Mass per unit volume of a material.

Derived unit A unit obtained by combining different SI units. A unit obtained by combining different SI units.

Time The interval between two events The interval between two events

Temperature Is measured using a thermometer. Is measured using a thermometer.

Graph Visual display of information or data that is used to detect patterns Visual display of information or data that is used to detect patterns A line graph shows a relationship where the dependent variable changes due to a change in the independent variable. A line graph shows a relationship where the dependent variable changes due to a change in the independent variable.

Line graph The scale should make the graph readable. The scale should make the graph readable. The x-axis should always be used for the independent variable. The x-axis should always be used for the independent variable. Units of measurement must be consistent. Units of measurement must be consistent.

Bar graphs Compare information collected by counting. Compare information collected by counting.

Circle graphs Show how a whole is broken into parts. Show how a whole is broken into parts.

What axis should always be used for the independent variable? The x – axis The x – axis

What is the difference between the Independent and Dependent Variable?? The dependent variable is the variable that changes when the independent variable is altered - that is, the dependent variable is what changes as a result of what you did in the experiment.

Drawing a Graph by Hand * Always use a straight edge to make any marks or lines on your graph *Always use as much of the graph paper as possible

Where do I begin? *Identify the independent and dependent variables of your experiment * Organize your data into a chart or table

Steps to follow: *Write the label of the independent variable on the x-axis. Be sure to include the units that were used. *Write the label of the dependent variable on the y-axis. Be sure to include the units that were used.

Steps to follow continued: *Subtract the lowest value of the independent variable from the highest value. This gives you the range for the independent variable. * Mark off the x-axis in a way that best fits the range of the independent variable. Spread out the data as much as possible. *Number the x-axis. Don’t forget to label zero if your data begins at zero.

Steps to follow continued: *Repeat the above steps for the y-axis *Plot your data values on the graph. Make each mark a small, dark dot. *Draw the best straight line or curve that best fits your data markings. Not every dot must fall on the line!

What is extrapolation? Extrapolation of data is the prediction of data beyond the graphed data data points

What is interpolation? *Interpolation is the prediction of data located between known data points.

Let’s Extrapolate !! How many grams of NaCl will dissolve in 150ml of water? 10g of NaCl

Let’s Interpolate!! How many grams of NaCl will dissolve in 100ml of water? 6.7g of NaCl