Lecture 7 Representing Data Ozgur Unal NIS – CHEMISTRY Lecture 7 Representing Data Ozgur Unal

Graphing A graph is a visual display of data. Three types of graphs: Circle graphs Bar graphs Line graphs A circle graph (or a pie graph) is used to show how some fixed quantity is broken down into parts. Check Figure 2.14 on page 55. To create a circle graph, start with the total amount, and then calculate the ratio of each component in the total. Find out the angles for each pie.

Bar Graph Bar graph shows how a quantity varies across categories. Bar graphs are also used to show the frequencies or amount of occurrences of events. For example, the number of NIS students in each grade.

Line Graphs Line graphs show how a quantity (dependent variable) changes with respect to the other (independent variable). Independent variable is shown on the x-axis. Dependent variable is shown on the y-axis. Sometimes we draw best fit line to show the linear relationships between the variables.

Line Graphs The relationship between the variables in a line graph can be analyzed by using slope (or steepness) of the line. A positive slope indicates that the dependent variable increases as the independent variable increases. A negative slope indicated that the dependent variable decreases as the independent variable increases slope = rise / run slope = ∆y/∆x

Calculate the slope of the line below. Line Graphs Calculate the slope of the line below.

Interpreting Graphs When points on a line graph are connected, the data is considered to be continuous. Continuous data allows you to read the value from any point that falls between the recorded data. This process is called interpolation. You can also extend a line beyond the plotted points in order to estimate values for the variables. This process is called extrapolation. Extrapolation might be less reliable than interpolation. Why?

Lecture 8 Properties of Matter Ozgur Unal NIS – CHEMISTRY Lecture 8 Properties of Matter Ozgur Unal

Properties of Matter States of matter: Solid, liquid, gas etc. Matter with a uniform and unchanging composition is called a substance. Example: Salt, sugar, oxygen etc. Most common substances exist as solids, liquids and gases, which have diverse physical and chemical properties. States of matter: Solid, liquid, gas etc. Plasma is another state of matter. It exists in stars, lightning bolt etc.

States of Matter A solid is a form of matter that has its own definite shape and volume. The particles of matter in a solid are tightly packed. When heated a solid slightly expands. A liquid is a form of matter that flows, has a constant volume and takes the shape of its container. The particles in a liquid are not rigidly held in place and are easily closely packed than the particles in a solid. Like solids, liquids tend to expand when heated.

States of Matter A gas is a form of matter that not only flows to conform to the shape of its container but also fills the entire volume of its container. The particles in a gas are very far apart, therefore gases are easily compressed. The word vapor refers to the gaseous state of a substance that is solid or liquid at room temperature. Steam is a vapor.