Chapter 1 – Section 1 What is Science?

Steps to the Scientific Method 1. Identify Problem or Question 1. Identify Problem or Question 2. Research and Gather Information 2. Research and Gather Information 3. Form a Hypothesis 3. Form a Hypothesis 4. Experiment 4. Experiment 5. Analyze Data 5. Analyze Data 6. Draw a Conclusion 6. Draw a Conclusion

Identify Problem or Question U Usually developed from a question you want to answer Use clear terms Identify variables in the question Ex: Does a certain type of cat litter irritate cats’ skin?

Research and Gather Information Research what is known about topics related to the question (what is cat litter made of?) Sources might include the internet, magazines, encyclopedias, videos, interviews Information is gathered before making a hypothesis

Research and Gather Info, con’t Information can be in the form of observations (ex: the cats are itchy and biting their skin) Information can be results from other experiments or field studies

It is Time for An Example! Question: Does acid rain affect plant growth? Question: Does acid rain affect plant growth? What are some things you could look up that would relate to our question? What are some things you could look up that would relate to our question? The pH of acid rain How pH/acid rain affects plants Where acid rain is found on Earth Results from other people’s experiments

Form a Hypothesis An explanation that can be tested A hypothesis is written in “If-then” format Should be very specific Ex: If cat litter contains deodorant, then it will irritate the cats’ skin.

It’s Time for an Example! Problem: Does acid rain affect the growth of a Pothos plant? Problem: Does acid rain affect the growth of a Pothos plant? Write a hypothesis for the problem. Write a hypothesis for the problem. If acid rain with a pH of 4 is sprayed on a Pothos plant for three weeks, then the plant growth will be slower than the control plants.

Test the Hypothesis (Experiment) Test the hypothesis in controlled settings Test the hypothesis in controlled settings Can contain only one variable (can test only one characteristic at a time) Can contain only one variable (can test only one characteristic at a time) Use senses to gather information during experiment Use senses to gather information during experiment

Experiment, continued Should have one control group that is not tested Should have one control group that is not tested Control group sets the standard for the test groups’ results to be compared to Control group sets the standard for the test groups’ results to be compared to example: A group of Pothos plants is not sprayed with acid rain Can have multiple experimental groups Can have multiple experimental groups

Variables??? A variableis a part of the experiment that can be changed A variable is a part of the experiment that can be changed There are two types of variables There are two types of variables Independent variable - the variable you control/test (ex: type of cat litter) 1. Independent variable - the variable you control/test (ex: type of cat litter) Dependant variable - the variable you measure (ex: skin irritation) 2. Dependant variable - the variable you measure (ex: skin irritation)

Time for an Example! Problem: Does acid rain affect plant growth? Problem: Does acid rain affect plant growth? Identify the independent variable Identify the independent variable Acid rain Identify the dependant variable Identify the dependant variable Plant growth

Analyze Data Decide which data is important and which data is not related to your hypothesis Decide which data is important and which data is not related to your hypothesis Create graphs for your data Create graphs for your data You should be able to recognize errors made during the experiment which may affect your data You should be able to recognize errors made during the experiment which may affect your data Look for patterns in your data Look for patterns in your data

Time for an Example!

Draw a Conclusion You should accept or reject your hypothesis based on your data You should accept or reject your hypothesis based on your data Explain the scientific reason for your results Explain the scientific reason for your results Explains mistakes or poor experimental design as a reason for unusual data Explains mistakes or poor experimental design as a reason for unusual data Based on data and research Based on data and research Logical answer to a question Logical answer to a question

Time for an Example ! Write a possible conclusion for our acid rain example. Write a possible conclusion for our acid rain example.

The answer is…. Plants prefer water that has a neutral pH. The acid rain has a low pH which means it would damage cells. Damaged cells will not grow as quickly. Also, if cells are damaged, they may not divide correctly causing the plant to grow slowly. However, a pH of 4 did not stop all growth, it only slowed it. It may take more than 4 weeks to see a real difference in the growth of the two groups of plants Plants prefer water that has a neutral pH. The acid rain has a low pH which means it would damage cells. Damaged cells will not grow as quickly. Also, if cells are damaged, they may not divide correctly causing the plant to grow slowly. However, a pH of 4 did not stop all growth, it only slowed it. It may take more than 4 weeks to see a real difference in the growth of the two groups of plants

Theory Explains events using scientific knowledge Results of many experiments support the theory Ex: cell theory says all living things are made of cells

Theory, con’t Theories change over time as more evidence is collected Theories usually explain why something happens

Laws  A statement about how things work in nature that seems to always be true  Less likely to change than a theory  Ex: Newton’s Universal Law of Gravitation that says all things are attracted to each other by the force of gravity.

Units of Measurement MMass measures the amount of matter in an object MMeasured with a balance UUnits are grams (g)

Units of Measurement, con’t VVolume is the amount of space an object takes up VVolume of solids are calculated by l x w x h VVolume of liquids are measured with a flask, graduated cylinder, or beaker LLiquid units are liters (L). SSolid units are cubic centimeters (cm 3 )

 Distance is measured in meters (m) using a ruler or meterstick.  Time is measured in seconds (s) using a stopwatch.  Weight is the amount of gravity pulling on an object and is measured with a spring scale. The units are Newtons (N)