Nature of Science

Scientific research starts with a problem or a question. That question becomes the basis for a hypothesis, or testable statement. Sally decided to run an experiment that tests this hypothesis: Earthworms prefer moist, loamy soil over dry, sandy soil. What question MOST LIKELY generated her hypothesis?

• How do earthworms move?
• Why do earthworms move out of the ground?
• In what kind of soil would you find the most earthworms?
• Why do you find dead earthworms in the driveway after a rainstorm? 

Sally and Sue were investigating the topic of friction in science. They used a small car and a ramp as seen in the picture to test what they were learning. They knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. They planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. 
What would be the BEST research question to guide the girls' experiment?

• Will the car travel fastest on the glass surface?
• How does the angle of the ramp affect the speed of the car?
• Do rougher surfaces tend to create more friction than smooth surfaces?
• Does the amount of surface area affect the friction on the moving car? 

 Jonathan is learning about water conservation. He learns that the average household in the United States uses 293 gallons of water per day. Jonathan makes a chart that shows the percent of water that each indoor fixture uses in the average U.S. household. He would like to use this chart to determine which indoor fixture uses the most water in his own home. Then, he can replace this fixture with a more efficient, water-saving fixture. 
What would be an appropriate research question to guide Jonathan's research project?

• How can we use less water at home?
• How can the United States conserve water?
• Which fixture uses the most water in our home?
• Do shower heads use more water than sink faucets?

Sir Isaac Newton determined that gravity has a fixed acceleration on Earth. The earth pulls objects towards it with a fixed acceleration at -9.8 m/s². This is a _____________ ____________, as it states a scientifically accepted fact about the natural world.

• Scientific law
• Scientific theory
• Natural hypothesis
• Scientific evaluation

- can be disproved
- supported with repeated testing
- valid if there is no evidence to dispute it
This list of terms BEST describes a

• hypothesis
• law
• theory
• variable

When can a law or theory be changed?

• When new technology is developed
• After another scientist does an experiment
• Never; once it is a law or theory it is impossible to change it
• After many experiments and much more data has been collected

Scientific hypotheses, theories, and laws are all vital to the development of scientific ideas. They are all vital, but they are not equal. They actually represent different types of ideas, with varying degrees of strength. The strength of a scientific idea is based in large part on how well it allows us to predict what will happen in certain situations.
Rank the three, beginning with the strongest.

• Law, Theory, Hypothesis
• Theory, Law, Hypothesis
• Theory, Hypothesis, Law
• Hypothesis, Theory, Law

A scientific theory

• is used to prove hypotheses
• is used to prove a scientific law
• is simply a claim or guess by a scientist
• is a well-supported, widely accepted explanation

Maya's father told her that hummingbirds like to drink the nectar from red flowers. Maya noticed that most of the hummingbird feeders in the store were made of red plastic. She wondered if this were really true. She decided to conduct an experiment to see if hummingbirds really preferred red flowers to other colors. Maya hung three bottles, upside-down, in her garden. One was red, one was green, and the last one was clear. She filled the bottles with the same sugar solution and screwed a drip nozzle into each one. Then she waited and watched.
What is the independent variable in this experiment?

• The color of the feeder
• The location of the bottles
• The amount of sugar solution
• How much hummingbirds ate

Earthworms, like the one seen here, live in soil. Bennie wondered how changes in the moisture content of the soil would affect the movement of worms. He wanted to design an experiment to test his idea. What would be Bennie's manipulated (independent) variable in the experiment?

• Size of the worms

• Moisture of the soil

• Movement of the worms

• Temperature of the soil