Applied Science - Science and Math (5A) Post Lab
 OBJECTIVES: Exploring different types of graphs. Interpreting line graphs. VOCABULARY: extrapolate interpretation line graph MATERIALS:  worksheet Students interpret data on California population.
 BACKGROUND: A graph is a pictorial presentation of a relationship among 2 or more items.  Graphs can be used to easily visualize a mathematical relationship.  Define the axis of a graph.  Point out the vertical (y axis) and horizontal (x axis) components.  In graphing, the x is considered the independent variable, whereas the y is the dependant variable (y is dependant on x).  In a common example, y represents the number of people and x represents the year in which the number was counted. Students usually see graphs that are part of a rectangular Cartesian coordinate system.  This system is two dimensional.  The term "Cartesian" is derived from the French mathematician and philosopher Descartes (1596-1650) who was noted for his logical analysis and mechanical interpretation of the physical world.  Cartesian coordinates help locate a point by using a reading from the x axis and one from the y axis.  For instance, in the graph to the right, point A is located by finding its x and y axis. PROCEDURE: The student constructed a bar graph in lab.  In this activity, students look at a line graph and ask themselves questions about the graph to extrapolate an answer.  Extrapolate means that students will predict or extend how the graph will continue.  The points on the graph can be read from the x and y axis.    The worksheet revolves around the population of California.  If located in another state, make this graph more representative of your area.  California is now the most populous state in the United States, with about 28 million people.  New York was the most populous state up until 1989.  According to this graph, it looks as if California will be the leader for a long time to come.    Students are learning to extrapolate the future by using past data.  This is a common practice in determining future trends.    ANSWERS:    2.  increased, 3.  19 million, 4.  double, 5.  run out of space to live, shortage of housing, not enough food, increased use of natural resources (timber, water, oil, etc) and (5) pollution increase