THE SCIENTIFIC METHOD

Blown AwayHead Lice Meet Hair Dryer of DeathHead lice are becoming indestructible. A study found as many as 80% ofthe bugs are resistant to insecticides in over-the-counter shampoos, andresistance will only increase. Evolutionary biologist Dale Clayton mayhave a new line of attack.Clayton, who usually studies lice on bird feathers, stumbled onto hissolution after a major research setback. When he moved his laboratoryfrom England to the University of Utah a decade ago, his entire lousecollection perished in the dry desert air. Soon after, his 8-year-old camehome from school with head lice. He wondered if human head lice couldalso be killed by drying them out. “It was sort of a forehead slapper,”Clayton says. After conventional hair dryers failed, Clayton came up with theLouseBuster, a 10-pound device resembling a vacuum cleaner that desiccates(dries out) the bugs with a jet of 140-degree air (140° F). “It’s a pretty brutalassault,” he says. Tests show the invention is both safe and effective, eradicating80% of live lice and 98% of eggs, leaving survivors unable to breed. And, Claytonsays, “it will be awfully hard for lice to develop resistance.” Source: Emily Saarman, “Blown Away-Head Lice Meets Hair Dryer of Death,” Discover Magazine,February 2007

STEPS• 1. State the problem.

– In the form of a question

• 2. Formulate a hypothesis.– Write as an “If….then….because…”

statement.

• 3. Test the hypothesis with a controlled experiment.– Parts:

• Be sure to use a large sample size• Control Group: gives the basis for comparison

– Ex.• Experimental Group: tests ONE SPECIFIC variable

– Ex.• Independent Variable: the condition that is changed by the

scientist– Ex.

• Dependent Variable: the condition that results from the change

– Ex.

• 4. Make observations – Examine and describe using your senses.– Collect and record data/information

• An OBSERVATION is determined using the senses (sight, sound, taste, hearing, touch) and instruments (microscopes, thermometers). – Ex.

• An INFERENCE is an interpretation of your observations.– Ex.

• 5. Come to a conclusion, based on prior knowledge and data collected.

• Ex.

• 6. Experiment MUST be repeatable to verify data and ensure accuracy.