Chapter 1 The Nature of Science

Do Now Try to write down the steps a scientist might use to solve a problem – this is called the scientific method. –Hint – there are 6 steps

1.2 The Scientific Method Suppose you knew nothing about science How would you explain why it rains???

1.2 The Scientific Method If someone didn’t believe your explanation, could you prove it??? Why or why not???

1.2 The Scientific Method Since the beginning of human history, people have tried to explain natural events (like rain). Because of limited information, they may have come up with ideas that seem silly to us today.

1.2 The Scientific Method We now assume that all events in nature have a natural cause. We try to arrange a series of observations or tests to learn what these causes are. The goal of science is to understand the world around us and the scientific method is what distinguishes science from non-science.

1.2 The Scientific Method The scientific method is a frame of mind that involves curiosity. Curiosity spurs a scientist to ask questions. The scientific method also includes a refusal to accept explanations without evidence or proof. This “prove it” attitude makes scientists investigate ideas and develop explanations.

Steps to the Scientific Method Organized Common Sense 1.Observing and stating the problem 2.Forming a hypothesis 3.Testing the hypothesis 4.Recording and analyzing the data 5.Forming a conclusion 6.Replicating the work

Scientific Method Video YouTube - Chemistry Music Video 1: The Scientific MethodYouTube - Chemistry Music Video 1: The Scientific Method 3 minutes

Graphing A graph is a diagram representing a system of connections or interrelations among two or more things by a number of distinctive dots, lines, bars, etc Graphs have an X axis (horizontal) and a Y axis (vertical) It is a great way to present scientific data because it is easier for people to understand than a bunch of numbers

Graphing Activity We will start a worksheet on graphing in class and then you will finish it for homework. Put 2 graphs per piece of graph paper Skip question #3

Do Now Why do scientists graph their data? Name 2 types of graphs. Is the X axis horizontal or vertical? Is the Y axis horizontal or vertical?

1. Observing and stating the problem Observation – leaves change color in autumn Why????

2. Forming a Hypothesis Hypothesis – possible explanation, preliminary conclusion or even a guess about some event in nature It gets cold and that causes the leaves to change color

3. Testing the Hypothesis Perform an experiment - In July, take a small tree growing in a pot and place it in a growth chamber set to autumn temperature levels. - If our hypothesis is right, the leaves should change color. - If the leaves do change color, would we know if it was definitely due to the temperature?

3. Testing the Hypothesis Not really!!! There are factors other than temperature that are different between our tree in the growth chamber and a tree growing outside. Our tree is growing in a small pot. Our light is not natural light. Etcetera

Variable A variable is the factor that is isolated and tested in an experiment. In a good experiment, all factors other than the variable should be kept the same. Our variable is the temperature in the growth chamber.

Types of Variables Variables are things that may be expected to change during the course of the experiment. –The investigator deliberately changes the independent variable. (CAUSE) –He or she measures the dependent variable (EFFECT) to learn the effect of changing the independent variable. –To eliminate the effect of anything else that might influence the dependent variable, the investigator tries to keep standardized variables constant.

Control We need a control, which is the part of an experiment that does not contain the variable (temperature) Grow a second tree in a pot an place it in a growth chamber also. But, set the temperature in this chamber to normal summer temperatures. Now, if the leaves change color we can be more sure it was due to the colder temperature.

4. Recording and Analyzing Data As you perform the experiment you must collect data by recording observations and information In our experiment, we could count the number of leaves that changed color and the time it took for them to do so. Then you must analyze the data by putting it in tables and graphs

5.Forming a conclusion Yahoo! Video Detail for Why do leaves change color in the fall? Yahoo! Video Detail for Why do leaves change color in the fall? Now we have to decide if our hypothesis is true. We look at our data – does it support our hypothesis? In our experiment, if only the leaves on the tree in the colder chamber change color, we may decide that we confirmed our hypothesis. If the leaves of neither or the leaves of both trees change color, we may reject our hypothesis.

6. Replicating the work The original researcher must be able to reproduce the experimental results. Other researchers should also be able to reproduce the experiment.

Hypothesis and theories Theory – when a hypothesis is tested and confirmed often enough that it is unlikely to be disproved by future tests Powerful time tested concept that makes useful and dependable predictions about the natural world

1.2 The Scientific Method Galileo was the first scientist credited with using the scientific method. He recorded the series of steps he used to investigate falling objects. The scientific method is not only used by scientists. We all use the scientific method every day!!!

Scientific Method Video YouTube - The Scientific Method Video 3 minutes

Activity – Identifying Variables Work in groups of 2 Read each scenario and try to figure out the –Independent variable –Dependent variable –Standardizing variables –Control Group **Finish what you can in class and do the rest for homework.

Do Now What is an independent variable? What is a dependent variable? What is a control group?

A Universal Language – The Metric System YouTube - Metric & Standard Measurement Systems

Metric System Science works best when scientists read each other’s papers, check each other’s experiments, and argue about what results mean. To do this they need a universal system of measurement to present their findings. Scientists use the metric system of length, volume, mass, and temperature when describing experiments and data.

Metric System Decimal system based on certain standards and scaled on multiples of 10: –Kilo – 1000 –Basic Unit –Centi – 1/100 –Milli – 1/1000 –Micro – 1/1,000,000

Metric System Do you know the common metric units?? –Length? –Volume? –Mass? –Temperature?

Length Meter – basic unit of length in the metric system Equivalent to 39.4 inches (a little longer than a yard) –Kilometer (1000 meters) –Meter –Centimeter (1/100 of a meter) –Millimeter (1/1000 of a meter)

Volume Volume - amount of space an object takes up Cubic Meter – basic unit of volume for solids in the metric system Liter – basic unit of volume for liquids in the metric system –Kiloliter (1000 liters) –Liter –Centiliter (1/100 of a liter) –Milliliter (1/1000 of a liter)

Mass and Weight Mass – measure of the amount of matter in an object Weight – a measure of the pull of gravity on the mass Weight can change – mass never changes (space) Gram – basic unit of mass in the metric system –Kilogram (1000 grams) –Gram –Centigram (1/100 of a gram) –Milligram (1/1000 of a gram)

Temperature Celsius Scale – metric temperature scale Water freezes at 0 o C Boils at 100 o C Each Celsius degree is 1/100 of the range between freezing and boiling –Normal Human Body Temperature is 37 o C –Room Temperature is approximately 21 o C

Metric System Activity Conversion Worksheet Finish what you can in class and do the rest for homework

Do Now What is the basic metric unit of measurement for length? What is the basic metric unit of measurement for volume of a liquid? What is the basic metric unit of measurement for mass? What is the basic metric unit of measurement for temperature?

1.3 Science: “Facts” and “Truths”

Fact or Truth Scientific knowledge is a constantly changing body of observations Many “scientific facts” of the past are now know to be false (the earth is flat, the sun revolves around earth, etc) Facts are the best explanations of the world around us developed so far Some of the things you learn in this class may sometime be proven false

Fact or Truth If a fact is found to be false  our knowledge has increased - we have not failed Science continues to advance our understanding of the world

How to Study Science Don’t try to memorize individual facts – there are too many!! Arrange facts in groups – according to subjects See how things are inter-related Science is a process – try to see the thinking behind the experiments we discuss

Science and Human Values An important goal of science is to be objective But, this does not always happen – scientists are people too! They have different opinions, emotions, likes and dislikes –Energy –Animal and human experimentation Data can be misinterpreted or misapplied to prove a particular point

Science and Human Values Studying science makes us all more informed Understanding it decreases the dangers posed by misinterpretation or misleading information –Ex. nuclear power, acid rain, chemicals in food and water

The Spaceship called Earth Earth is beautiful when seen from space Our species has rapidly developed the ability to change the earth for both the better and the worse The earth is not a planet without end. It is more like a spaceship with a living cargo, carrying limited amounts of supplies We must take care of what we have and prepare for the future

Activity Scientific Method Study Guide Fill it out using your notes and use it as a study guide