The Nature The Nature of Scienceof Science

Chapter 1 Chapter 1

Section 1Section 1

Essential QuestionsEssential Questions

What are the steps scientists use to solve What are the steps scientists use to solve problems?problems?

Why do scientists use variables?Why do scientists use variables? How do science and technology differ?How do science and technology differ? What are dependent variables?What are dependent variables? What are independent variables?What are independent variables?

ScienceScience Three categories – Three categories –

1.Life1.Life

2. Earth2. Earth

3. physical3. physical Explains Explains natural worldnatural world.. Explanations can be modifiedExplanations can be modified Scientists investigate by Scientists investigate by observation, observation,

experimentation, and modelingexperimentation, and modeling

Scientific MethodScientific Method

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

Scientific MethodScientific Method

Make an ObservationMake an Observation Ask a questionAsk a question Form a hypothesisForm a hypothesis Experiment/ Collect dataExperiment/ Collect data Draw a conclusionDraw a conclusion

Every Experiment Must Have:

Independent variable – The variable that Independent variable – The variable that the scientist changesthe scientist changes

Dependent variable – changes as other Dependent variable – changes as other variables changevariables change

Control – standard by which test results Control – standard by which test results are comparedare compared

Constant – variable that does not changeConstant – variable that does not change

Morgan wants to know which detergent works best for Morgan wants to know which detergent works best for removing mustard stains. She purchased 3 white cotton t-removing mustard stains. She purchased 3 white cotton t-shirts, Brand A detergent, and Brand B detergent.shirts, Brand A detergent, and Brand B detergent.

She put 1 ounce of mustard on each pocket of the shirts. She 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 let the mustard sit for 8 hours before washing each shirt in her washing machine.her washing machine.

She washed each shirt on the same cycle and water She washed each shirt on the same cycle and water temperature for 1 hour using each brand of detergent and temperature for 1 hour using each brand of detergent and washed the 3washed the 3rdrd shirt without any detergent. She then shirt without any detergent. She then compared the 3 shirts to see if the stains were removed.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 A had a light stain.

The shirt washed in Brand B had no stain.The shirt washed in Brand B had no stain.

The shirt washed without detergent had a dark stain.The shirt washed without detergent had a dark stain.

Observation- Walmart sells different brands Observation- Walmart sells different brands of detergentof detergent

Question- Which brand of detergent works Question- Which brand of detergent works best for removing mustard stains.best for removing mustard stains.

Hypothesis- If I wash t-shirts in Brand A and Hypothesis- If I wash t-shirts in Brand A and Brand B detergent, then Brand A will be Brand B detergent, then Brand A will be better at removing mustard stains.better at removing mustard stains.

Experiment- She tested her hypothesis.Experiment- She tested her hypothesis. Conclusion- Brand B was better at removing Conclusion- Brand B was better at removing

mustard stains than Brand A.mustard stains than Brand A.

Independent Variable- The detergent Independent Variable- The detergent brandsbrands

Dependent Variable- The darkness of the Dependent Variable- The darkness of the stain.stain.

Control- The shirt washed without Control- The shirt washed without detergent.detergent.

Constants-Constants-

White t-shirtsWhite t-shirts Mustard (1 ounce)Mustard (1 ounce) Stain on pocketStain on pocket Let sit 8 hoursLet sit 8 hours Same machineSame machine Same cycleSame cycle Same water temperatureSame water temperature Washed for 1 hourWashed for 1 hour

ModelsModels Represents idea, event, or objectRepresents idea, event, or object Helps people understand Helps people understand

Theories and LawsTheories and Laws

Theory – explanation based on Theory – explanation based on observations and investigationsobservations and investigations

ex. The Big Bang Theoryex. The Big Bang Theory

Law – always seems to be trueLaw – always seems to be trueEx. Newton’s Laws of MotionEx. Newton’s Laws of Motion

ScienceScience

Deals with natural worldDeals with natural world Does have limitationsDoes have limitations