Variables Notes Nature of Science Unit See corresponding

Variables Notes �Nature of Science Unit �See corresponding notes to fill in blanks for completion then paste into composition/lab notebook �Mr. Ben Thompson � 7 th Grade Science �Fulbright Jr. High �Bentonville, Arkansas

Variables �Variable – a factor that can change in an experiment �Controlled Experiment – experiment where only one variable is changed �Independent Variable – (also called manipulated variable) the variable that is changed on purpose in an experiment – what do I change?

Variables �Dependent Variable – (also called responding variable) the variable that changes in response to the independent variable – what do I observe/measure? �Controlled Variable – (also called a Constant) – a variable that must be kept the same throughout the entire experiment – what do I keep the same? �The Control – the part of the experiment that remains unchanged and is used to detect and measure any effects of unknown variables

Hypothesis �Hypothesis – a possible explanation for a question or problem (an educated prediction) �IF. . . THEN……statement �Must be testable!

Y - axis D ependent R esponding Y - Axis X - axis Manipulated I ndependent X - Axis

Mean, Median, Mode, Range �Mean – add all of the numbers and divide by the total number of numbers in the list. �Median – the middle number in a list of numbers when ordered smallest to largest. �Mode – the number that appears most often in a list of numbers. �Range – the difference between the largest and smallest number in a list of numbers. Subtract the smallest number from the largest number.

Identifying Variables - Practice Esther became interested in insulation while her parent’s new house was being built. She decided to determine which insulation transferred the least heat. She filled each of 5 jars half-full with water. She sealed each jar with a plastic lid. Then she wrapped 4 jars with a different type of insulation and left 1 jar with no insulation. She thinks the thicker insulation will transfer less heat. She put the jars outside in the direct sunlight. Later, she measured the temperature of the water in each jar.

Identifying Variables - Practice Sandy heard that plants compete for space. She decided to test this idea. She bought a mixture of flower seeds and some potting soil. Into each of 5 plastic cups she put the same amount of soil. In the first cup she planted 2 seeds, in the second cup she planted 4 seeds, in the third cup 8 seeds, and in the fourth cup she planted 16 seeds. In the last cup she planted 32 seeds. After 25 days, she determined which set of plants was the tallest.