The Nature of Science Chapter 1 Section 1

Essential Questions  What are the steps scientists use to solve problems?  Why do scientists use variables?  How do science and technology differ?  What are dependent variables?  What are independent variables?

Science  Three categories – 1.Life 2. Earth 3. physical  Explains natural world.  Explanations can be modified  Scientists investigate by observation, experimentation, and modeling

Scientific Method  Organized set of investigation procedures used to solve a problem or answer a question.

Scientific Method  Make an Observation  Ask a question  Form a hypothesis  Experiment/ Collect data  Draw a conclusion

Every Experiment Must Have:  Independent variable – The variable that the scientist changes  Dependent variable – changes as other variables change  Control – standard by which test results are compared  Constant – variable that does not change

Morgan wants to know which detergent works best for removing mustard stains. She purchased 3 white cotton t- shirts, Brand A detergent, and Brand B detergent. She put 1 ounce of mustard on each pocket of the shirts. She let the mustard sit for 8 hours before washing each shirt in her washing machine. She washed each shirt on the same cycle and water temperature for 1 hour using each brand of detergent and washed the 3 rd shirt without any detergent. She then compared the 3 shirts to see if the stains were removed. The shirt washed in Brand A had a light stain. The shirt washed in Brand B had no stain. The shirt washed without detergent had a dark stain.

 Observation- Walmart sells different brands of detergent  Question- Which brand of detergent works best for removing mustard stains.  Hypothesis- If I wash t-shirts in Brand A and Brand B detergent, then Brand A will be better at removing mustard stains.  Experiment- She tested her hypothesis.  Conclusion- Brand B was better at removing mustard stains than Brand A.

 Independent Variable- The detergent brands  Dependent Variable- The darkness of the stain.  Control- The shirt washed without detergent.

 Constants-  White t-shirts  Mustard (1 ounce)  Stain on pocket  Let sit 8 hours  Same machine  Same cycle  Same water temperature  Washed for 1 hour

Models  Represents idea, event, or object  Helps people understand

Theories and Laws  Theory – explanation based on observations and investigations ex. The Big Bang Theory  Law – always seems to be true Ex. Newton’s Laws of Motion

Science  Deals with natural world  Does have limitations