*Variables: Properties or characteristics
- Controlled Variable- Independent Variable - Dependent Variable
Solving Scientific Puzzles
OBSERVATION is the act the act of noting or perceiving objects or events using senses.
Between 1984 and 1988, JohnHarte, professor at the University of California, studied amphibians: the Tiger Salamander. He noticed that tiger salamander was disappearing from their nature home, the slopes of the Rocky Mountainsof Colorado. The number of these amphibians falls by 65 percent. Harted wanted to discover the facts or reasons around the disappearance.
Bradford in 1988 looked for a species of small frog in thelakes of Sequoia and Kings Canyon National Park. The frog species used to live in those lakes; but for some reason, they had disappeared from 98 percent. Bradford reported his observation: he foundthat local amphibians (frogs, toads, and salamanders) were also disappearing. Amphibians are sensitive to their environment because their skin absorbs chemicals from water.
So, their disappearances fromtheir natural homes, was an alarm:
biologists considered that something was altering the environment.
The responsible of the careful observation is the core ofscientific investigation.
Harte had studied the Colorado salamander population for years. He had learned what they eat, how they behave, when they reproduce, and the conditions they live in. Frequent visitsto the ponds helped him realize the salamander population was decreasing in number. Records of the lakes’ conditions helped him to find an explanation.
OBSERVATIONS OF THE NATURAL WORLD
Hartequestioned why the number of salamanders was dropping. He talked to other scientists, he observed the organisms and environment in Colorado, and read scientific reports.
Then he was able to respond...