Name: ______Date: ______
Section 1.3 - Thinking Like a Scientist
In 1928, Alexander Fleming noticed that bacteria he was studying did not grow in the presence of a yellow-green mold. In 1945, Fleming shared a Nobel Prize for Medicine with Howard Florey and Ernst Chain, who led the team that isolated penicillin.
Alchemy
______developed the tools and techniques for working with chemicals.
Alchemy
Alchemists developed processes for ______and ______. They designed equipment that is still in use today including ______, flasks, tongs, ______, and the ______and pestle.
An Experimental Approach to Science
Lavoisier helped to transform chemistry from a science of ______to the science of ______that it is today.
An Experimental Approach to Science
Lavoisier designed a ______that could measure mass to the nearest 0.0005 gram. He also showed that ______is required for a material to burn.
The Scientific Method
The ______method is a logical, systematic approach to the solution of a scientific problem.
Steps in the scientific method include:
- Making observations
- Testing hypotheses
- Developing theories.
The Scientific Method
Making Observations
When you use your senses to obtain information, you make an ______.
The Scientific Method
Testing Hypotheses
A ______ is a proposed explanation for an observation.
The Scientific Method
An experiment is a procedure that is used to test a hypothesis. When you design experiments, you deal with variables, or factors that can change.
•The variable that you change during an experiment is the ______variable, or independent variable.
•The variable that is observed during the experiment is the ______variable, or dependent variable.
The Scientific Method
Developing Theories
Once a hypothesis meets the test of repeated experimentation, it may become a theory.
•A ______ is a well-tested explanation for a broad set of observations.
•A theory may need to be ______at some point in the future to explain new observations or experimental results.
The Scientific Method
Scientific Laws
A scientific ______ is a concise statement that summarizes the results of many observations and experiments.
A scientific law doesn’t try to ______the relationship it describes. That explanation requires a theory.
Manipulated vs. Responding Variable Practice
Directions: In each of the following examples, identify the manipulated variable (MV), the responding variable(RV), and any controls(C) that you can think of.
Identify the Controls and Variables
Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.Identify:
- Manipulated Variable: ______
- Responding Variable: ______
- Controls: ______
- What should Smithers’ conclusion be? ______
Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of "treatment" there is no change in the appearance of the green slime on either side of the shower.
Identify:
- Manipulated Variable: ______
- Responding Variable: ______
- Controls: ______
Bart believes that mice exposed to radiowaves will become extra strong (maybe he's been reading too much Radioactive Man). He decides to perform this experiment by placing 10 mice near a radio for 5 hours. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. he found that 8 out of 10 of the radiowaved mice were able to push the block away. 7 out of 10 of the other mice were able to do the same.
Identify:
- Manipulated Variable: ______
- Responding Variable: ______
- Controls: ______
Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes.
Identify:
- Manipulated Variable: ______
- Responding Variable: ______
- Controls: ______
Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which is a commercial hair product) affect the speed of hair growth". Her family is willing to volunteer for the experiment.
Describe a good experiment that would test Lisa’s question. Make sure to identify the MV, RV, and any controls.
______
Manipulated Variable: ______
Responding Variable: ______
Controls: ______