Standard Review: Scientific Method

At one point in time, many people thought disease was caused by fate or by incorrect behavior. Following the invention of the microscope, bacteria were discovered. After this, a new theory of what causes disease arose that was known as the germ theory.  Why was the original theory modified? 

• It quickly became obvious that germs cause disease.
• The person who invented the microscope became ill.
• New evidence prompted revision to the original ideas.
• The proponents of the germ theory had political power.

The theory of plate tectonics states that Earth’s crust is made of sections that move. Which of the following is NOT evidence that can be used to support the theory of plate tectonics?

• The sea floor is spreading apart from mid-ocean rifts.
• Mountains push up where two plates bump into each other.
• The same species of bird is found in North America and South America.
• The continents look as if they fit together like pieces of a jigsaw puzzle.

Joe tells Mai his theory about why sea turtles nest on the beach instead of in the ocean. He says, “The turtle eggs would sink to the bottom of the ocean, and the baby turtles would drown.” Joe says his uncle is a fisherman, who told Joe this information. Mai tells Joe that his theory is not scientific. Which explanation supports Mai’s evaluation of Joe’s theory?

• Joe’s idea is already a scientific law. 
• Joe’s idea is not supported by scientific evidence. 
• Joe’s idea is a good guess that can be tested by experiments. 
• Joe’s idea accurately explains why sea turtles nest on the beach. 

 A biologist is investigating the effects of growth hormone on the rate of metamorphosis in butterflies. Which of the following methods of investigation would work best for the biologist investigating any possible effects?

• models
• controlled experiments
• systematic observations
• random sampling of populations

The independent variable is the ONE thing you _____.

• change on purpose
• control or keep constant
• measure

Why do we want to test one variable at a time?

• Because it is hard to setup a data table with more
• To know what is causing the changes. This helps us understand cause and effect.
• It is what has always been done

What is a constant/control in an experiment?

• Things that do not change in a experiment. It's the variable that stays the same. You can have many variables stay the same.

• It's the variables that the scientist changes in the experiment

• It's the variables that are being measured in an experiment

Jackie sets up an investigation to find out how many paperclips she can pick up with an electromagnet. She takes a long iron nail, wraps insulated wire around it 40 times, and connects the wire ends to the opposite terminals of a D-cell battery.

Jackie touches the tip of the nail to a pile of 100 paperclips and picks up 15 of them. She tries the investigation again and picks up 15 paperclips. Jackie concludes that her electromagnet can pick up 15 paperclips. What should Jackie do to improve her investigation?

• Jackie should use a regular magnet and not an electromagnet.

• Jackie should use a different type of battery.

• Jackie should do more trials to make sure her results are valid.

• Jackie should begin with more than 100 paperclips.

Which of the following is a scientific observation? 

• The potato is brown in color.
• The potato tastes the best.
• The potato may cause allergies.
• The potato smells funny. 

Justin blows his nose, but mucus seems to leak through the tissue.  He decides to test which tissue holds up the best while sneezing.  What is the independent variable?

• sneezing
• Justin
• amount of tissue
• type of tissue