9/9/13 Chapter 1 Science Skills 1

CHAPTER 1: SCIENCE SKILLS

1.1 What is Science?

1.2 Using a Scientific Approach

1.3 Measurement

1.4 Presenting Scientific Data

Green = ? write in your notes

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1.2 USING A SCIENTIFIC APPROACH • Vocabulary

•  scientific method •  observation •  hypothesis

• Objectives • Describe the steps in a scientific method. • Compare and contrast facts, scientific theories, and

scientific laws. • Explain the importance of models in science. • Explain the importance of safety in science.

• manipulated variable •  responding variable •  controlled experiment

•  scientific theory •  scientific law • model

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SCIENTIFIC METHODS

•  scientific method - an organized plan for gathering, organizing, and communicating information

•  Goal of any scientific method: to solve a problem or to better understand an

observed event

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Example of a Scientific Method

Flow Chart

Scientific Method can vary from case to case

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IMPORTANT STEPS OF A SCIENTIFIC METHOD

•  Making Observations observation - information obtained through the senses

•  Forming a Hypothesis hypothesis - proposed answer to a question (an educated guess)

For a hypothesis to be useful it must be testable.

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IMPORTANT STEPS OF A SCIENTIFIC METHOD

•  Testing a Hypothesis - perform an experiment

•  variable - any factor that can change

• manipulated variable - variable that causes a change in another (independent)

• responding variable - variable that changes in response to manipulated variable (dependent)

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•  To examine relationship between MV & RV, use a controlled experiment - experiment in which

only one variable, the MV, is deliberately changed at a time

•  While RV is observed for changes, all other variables are kept constant or controlled.

IMPORTANT STEPS OF A SCIENTIFIC METHOD

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•  "What do I change?“ Answer: manipulated variable (independent)

•  "What do I observe?“ Answer: responding variable (dependent)

•  "What do I keep the same?“ Answer: controlled variable(s)

IMPORTANT STEPS OF A SCIENTIFIC METHOD

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•  Example:

Measuring the influence of different quantities of fertilizer on plant growth.

MV: RV: Controlled variables:

IMPORTANT STEPS OF A SCIENTIFIC METHOD

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•  Example:

Measuring the influence of different quantities of fertilizer on plant growth.

MV: amount of fertilizer used RV: growth in height and/or mass of plant Controlled variables: type of plant, type of fertilizer, amount of sunlight plant gets, etc. (factors that would otherwise influence RV if not controlled)

IMPORTANT STEPS OF A SCIENTIFIC METHOD

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•  Drawing Conclusions Was my hypothesis correct?

•  Developing a Theory Hypothesis supported in repeated experiments à

scientific theory - well tested explanation for a set of observations or experimental results

IMPORTANT STEPS OF A SCIENTIFIC METHOD

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•  Good theories •  are supported by data from lots of experiments/

trials. •  become stronger if new facts continue to support

them. •  can be revised or replaced as new data adds to

understanding. •  allow you to make accurate predictions. •  can never truly be proved.

IMPORTANT STEPS OF A SCIENTIFIC METHOD

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SCIENTIFIC LAWS •  After repeated observations or experiments, scientists

may arrive at a scientific law.

•  scientific law - statement that summarizes a pattern found in nature

•  i.e. •  Newton’s 2nd Law of Motion (F=ma) •  Hubble’s Law - Galaxies farther away from us

move away from us faster than closer galaxies

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SCIENTIFIC LAWS Vs. SCIENTIFIC THEORIES

•  A scientific law describes an observed pattern in nature without attempting to explain it. The explanations of such a pattern is provided by a scientific theory.

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SCIENTIFIC MODELS •  model - representation of an object or event

•  Purpose: makes it easier to understand things that might be too difficult to observe directly

•  Examples:

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SCIENTIFIC MODELS •  Examples:

* Constantly discovering new information so… new models are constantly replacing old models.

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WORKING SAFELY IN SCIENCE •  Dealing with materials that could be potentially

dangerous (flames, hot plates, electricity, chemicals, hot liquids, breakable glassware, etc.)

•  Need to use safe procedures when carrying out

investigations

•  Skills and Reference Handbook: Science Safety (page 868) has more information

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Look at each of the following drawings and explain why the laboratory activities pictured are unsafe.

A. B.

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Look at each of the following drawings and explain why the laboratory activities pictured are unsafe.

A. B.

Safety goggles should always be worn whenever working with chemicals, lab burners, or any substance that might get into eyes

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Look at each of the following drawings and explain why the laboratory activities pictured are unsafe.

A. B.

Safety goggles should always be worn whenever working with chemicals, lab burners, or any substance that might get into eyes.

Never heat a liquid in a closed container. The expanding gases produced may shatter the container.

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Look at each of the following drawings and explain why the laboratory activities pictured are unsafe.

C.

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Look at each of the following drawings and explain why the laboratory activities pictured are unsafe.

C.

When diluting an acid, pour the acid into water. Never pour water into the acid. Also, safety goggles and a lab apron should be worn when working

with chemicals.

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Is proper safety procedures being followed? If not why?

•  Gina is thirsty. She rinses a beaker with water, refills it with water, and takes a drink.

•  Bram notices the electrical cord on his microscope is frayed near the plug. He takes it to the teacher and asks for a new one.

YES or NO

YES or NO

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Is proper safety procedures being followed? If not why?

•  Gina is thirsty. She rinses a beaker with water, refills it with water, and takes a drink.

•  Bram notices the electrical cord on his microscope is frayed near the plug. He takes it to the teacher and asks for a new one.

YES or NO

YES or NO

Never drink from laboratory glassware. Substance in it

may have been poisonous & traces of poison may remain.

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Is proper safety procedures being followed? If not why?

•  Gina is thirsty. She rinses a beaker with water, refills it with water, and takes a drink.

•  Bram notices the electrical cord on his microscope is frayed near the plug. He takes it to the teacher and asks for a new one.

YES or NO

YES or NO

Never drink from laboratory glassware. Substance in it

may have been poisonous & traces of poison may remain.

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•  While washing glassware, Mike splashes some water on Evon. To get even, Evon splashes him back.

•  During an experiment, Lindsey decides to mix two chemicals that the lab procedure does not say to mix, because she is curious about what will happen.

Is proper safety procedures being followed? If not why?

YES or NO

YES or NO

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•  While washing glassware, Mike splashes some water on Evon. To get even, Evon splashes him back.

•  During an experiment, Lindsey decides to mix two chemicals that the lab procedure does not say to mix, because she is curious about what will happen.

Is proper safety procedures being followed? If not why?

YES or NO

YES or NO

Misbehaving is never acceptable in a laboratory!

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•  While washing glassware, Mike splashes some water on Evon. To get even, Evon splashes him back.

•  During an experiment, Lindsey decides to mix two chemicals that the lab procedure does not say to mix, because she is curious about what will happen.

Is proper safety procedures being followed? If not why?

YES or NO

YES or NO

Misbehaving is never acceptable in a laboratory!

Never mix chemicals unless directed to do so. The mixing might produce an explosive

substance.

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REVIEW •  What is the goal of a scientific method? •  What are three types of variables in a controlled

experiment? •  How does a scientific law differ from a scientific

theory? •  Why are scientific models useful?

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REVIEW •  What is the purpose of an experiment? A. to communicate data B. to test a hypothesis C. to prove a scientific law D. none of the above

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REVIEW •  Why are scientific models important? A. They prove scientific theories. B. They never change. C. They make it harder to understand things. D. They help visualize things that are very complex, very large, or very small.