1 Scientific Method

. What is Science? 2 Activity carried on by humans that is designed to discover information about the natural world. Organized inquiry into the natural world and its phenomena. Science is about gaining a deeper and often useful understanding of the world. Science is not exact or perfect. From time to time, scientific explanations may change as new data is presented. The process of testing and fine-tuning theories never ends as scientists try to gain new insights into old problems

What is the goal of Science? 3 What is the goal of Science? To develop an understanding of the natural universe which is free of human bias.

Scientist use the scientific method to solve problems. 4 Scientific Method Scientist use the scientific method to solve problems.

What is the Scientific Method? 5 An organized set of steps used to solve a problem. Is there a certain number of sets? NO! It is simply a logical way to solve a problem.

Can you form conclusions about something before you test it? NO! 6 Can you form conclusions about something before you make observations? NO!

EXAMPLE What is an observation???? (1) Observation: 7 (1) Observation: Something done through the five senses. “I don’t hit very well with my baseball bat.” (2) State the problem: “I need a bat that will allow me to hit better.” What is an observation????

(4)Test the Hypothesis through an experiment: (3)Form a Hypothesis: “If I use a different bat, then I will hit more home runs.” *Hypothesis must be testable! (4)Test the Hypothesis through an experiment: How could I set up this experiment????? 8

- Follow a few simple rules. 9 Performing a GOOD experiment What is a GOOD experiment? - It truly tests for what it is supposed to test for. How can we make sure that our experiment is a GOOD experiment? - Follow a few simple rules.

Performing a GOOD experiment 10 Performing a GOOD experiment Rules: #1. An experiment usually contains two variables. Independent Variable (manipulated) What the experimenter...YOU… changes. (2) Dependent Variable (responding) What happens because the IV changes. Type of bat More homeruns

Performing a GOOD experiment 11 Performing a GOOD experiment Rules: #2. All experiments need a control. What is a control?? A control is something to compare the experimental results to. What’s our control? Our regular bat.

Setting up the Experiment 12 Setting up the Experiment The experiment: I will hit 100 balls with 4 bats and compare the number of homeruns. How can I make sure that the bat is the only factor affecting the way I hit the ball?

Can you think of any others??? These are called CONSTANTS. 13 Ball thrown the same every time. Same type/age ball. Weather the same every day. Same number of hits every day. Same amount of sleep each night. Can you think of any others??? How can I make sure that the bat is the only factor affecting the way I hit the ball? These are called CONSTANTS. -They are the same in the experimental group and the control group. -They do not change

To make sure we are testing for what we said we are testing for. 14 To make sure we are testing for what we said we are testing for. Why do we need Constants?

15 Data Regular Bat

After the Experiment (5)Analyzing the data (6)Draw conclusions. 16 (5)Analyzing the data “What is the data telling me?” What did we learn? I hit more homeruns with bat #3. (6)Draw conclusions. Was the hypothesis supported? YES! What does this data mean for the future? -I will use bat #3. Regular Bat

How can we be sure that the results are real? 17 How can we be sure that the results are real? REPEAT THE EXPERIMENT!

18 What’s a theory? Scientific Theories are based on knowledge gained from many experiments. NOT A GUESS!

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Redi’s Experiment on Spontaneous Generation 23 Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. Uncovered jars PROCEDURE: Covered jars Controlled Variables: jars, type of meat, location,temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Several days pass Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Observation vs. Inference 24 Observation vs. Inference An observation is the information gathered using any of your senses. An inference is an explanation of the data based on facts but not on direct observation.

Inference vs. Observation 25 Inference vs. Observation Statement Observation Inference Object A is round and orange. X X Object A is a basketball. Object C is round and black and white. X Object C is larger than Object B. X Object B is smooth. X X Object B is a table-tennis ball. Object A is a basketball. Object B is a table-tennis ball. Object C is a soccer ball.

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When leaving a movie theater, a person notices that the sidewalk is now wet. If the person assumes it rained while watching the movie, the person is making 27 A a hypothesis B an inference C an observation D a prediction

A student wants to determine the effect of salt on the freezing point of water. A student adds 200 mL of pure water to three identical containers. To one container, 2 g of the salt is added; in the second container, 4 g of the salt is added; and in the third container no salt is added. The three containers are placed in the same freezer. The temperature of the water is measured every 10 min for one hour, and the observations are recorded in a data table. What is the independent variable in this experiment? 28 A the amount of salt added B the temperature measured C the type of salt used D the type of container used

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