Chapter 2 Data in Science

1. Chapter 2Data in Science

2. Section 1 • There are many tools that are used to conduct scientific experiments such as collecting, analyzing, and evaluating data. • Some examples of tools that are used are computers, graphs, pencils, meter sticks, and thermometers. • In different countries years ago countries had different systems of measurement like England used 3 grains of Barley placed end to end to stand for an inch.

3. In the1700s the French Academy of Science made an easier measurement system. The metric system is formed over the next 200 yrs. Its known as the International System of Units(SI) and is in powers of 10. • Length: Describes how long an object is. A meter is the basic SI unit of length. • Mass: The amount of matter in an object. Kilogram is the basic SI unit of mass and it is used find the mass of large objects. Grams are used to describe the mass of small objects. • Volume : Amount of space an object occupies. The volume of a liquid is expressed in liters. The volume of a solid is expressed in cubic centimeters.

4. Density: The amount of matter in a given object and is described by dividing the mass by the volume. Density=Mass/Volume • Temperature: Measurement of either the hotness or coldness of an object. Basic SI units used to measure Temp. is Kelvin Fahrenheit and Celsius. • Models are used to represent an object or system. Common types of models are : • Physical: Help understand certain concepts ex. Are airplanes, dolls, and drawings • Conceptual : ex. The big bang theory …Puts ideas together to explain or summarize something. • Mathematical : made up of mathematical equations & data. Can help predict weather & can have many variables. Models are important tools

5. A theory is an explanation for many hypothesis and observations. Models can sometimes help form theories. • A law is a summary of many experimental results and observations. Law tells you what happens not why it happens, and the law of conservation of mass says during a chemical change the mass of the material formed is the same as the total mass of the starting mateial.

6. Section 2 • First column in a data table is where the independent variables go. • Independent Variables: factors that an investigator change in an experiment. • Second column in a data table is where the dependent variables go. • Dependent Variables : factors that change due to the independent variable. • Controlled Parameters are factors that stay constant through an experiment Ex. Temp. and material used to study should be kept constant. • Variable Parameters are factors that change throughout an experiment Ex. Mass and volume can be if you want to study a relationship between two factors.

7. Section 2 Labeling columns is important Independent Variables Dependent variables & correct units should be included

8. Data tables are helpful in organizing data and Graphs help you understand the data& also makes it easy to identify trends and make predictions. • An axis is a reference line that forms 1 side of the graph, each axis has its own range, you subtract smallest value from the largest value on same variable. Ex. 53-40=13 13 is your range.

9. The scale is the size that’s used for each box or grid mark on the graph • Data points are plotted on graphs by putting a dot on graph for each pair of data. • Line of Best Fit is a line with some but not all data points • Remember to label your graph with a title. • Linear Graphs are graphs where relationship between ind. And dep. Can be shown with a straight line. • Nonlinear Graphs are graphs where relationship between the variables can’t be shown with a a straight line. • Variables are direct when both ind. And dep. Variable increase. • Variables are inverse when one variable increases while the other decreases.

10. Computers are good data organizers and they help scientist collect, organize, process, and display large amount of data.

11. Section 3 • Mathematics is used to answer ?s, making observations, conducting experiments, and also organizing data. • When using math to conduct experiments make sure you have the accurate data or else you’ll get inaccurate data. • Also don’t use broken equipment, the wrong tool or use the tool incorrectly. • Data must be reproducible in order for other people to agree with your conclusion. • Scientist find it helpful to use a single number to describe an entire data set when analyzing data.

12. Mean: is the number you get when adding the data and dividing the sum by the number of individuals. • Median: the value of the middle item when data is arranged in order by size. • Mode: the most frequently occurring value in a data set. • Slope : A measure of the slant of a line, the ratio of rise over run. Rise represents a vertical change, and Run represents a horizontal change. • Scientist can use the equation y=kx to represent their data. • X represents measurement of volume and k represents measurement of mass.

13. You can rearrange the formula for density Y=kx = m=DV Linear and nonlinear result in different relationships in data. Linear= line Nonlinear = no line , curve