Thinking Like a Scientist! The Scientific Method Thinking Like a Scientist!

The Nature of Science The goal of science is to understand the world around us! There are many branches of science: Biology (Living Environment) Earth Science Chemistry Physics

What is a scientific theory? A theory is a well-supported explanation of some aspect of the natural world. A theory is widely accepted by scientists because it is reliable. Theories have been tested repeatedly and have continuously yielded results that are supportive. Ex: The Theory of Evolution

Thinking like a scientist… Scientists don’t simply look for facts, they try to use those facts to solve larger mysteries. Ex. Mystery: How do plants use sunlight to convert CO2 and H2O into sugar? They understand that even mistakes teach you something, so it’s okay to experiment and have an unexpected outcome. They use the Scientific Method to answer the questions they have and solve problems.

Steps to the Scientific Method Call on I will call on some of you to share aloud. List List them on your paper. See See if you can recall the steps of the Scientific Method. Take Take 1 minute and turn to your partner.

The Scientific Method 1. Question Problems 2. Background Research 3. Hypothesis 4. Experiment 5. Collect & Analyze Data 6. Form & Report Conclusions

Question Develop a question about a problem that can be solved by experimentation.

Background Research Look up information to learn more about the problem/question you are trying to answer.

(based on your knowledge & research) Hypothesis Make an educated statement that you think will describe the results of the experiment. (based on your knowledge & research) FORMAT: If…then…because…

CREATE A HYPOTHESIS THAT CAN ANSWER THIS QUESTION. Let’s Practice! Question: Why is the moon visible at night, but not during the day? CREATE A HYPOTHESIS THAT CAN ANSWER THIS QUESTION.

Experiment Test your hypothesis.

Collect Data & Analyze Results Gather information from many trials and look for trends that tell you something new about the question/problem. Trial – Number of times you repeat experiment (At least 3x) Trend – Pattern in the data Direct, Indirect, Constant, Cyclic

Form & Report Conclusions Determine what the data YOU collected is showing you and tell others about your findings. AKA SHARE WHAT YOU LEARNED

Can you name the 6 steps of the Scientific Method? THINK Question: Can you name the 6 steps of the Scientific Method?

Scientific Experiments

Observation vs. Inference Observation – A true statement about an object that uses the 5 senses. Inference – A conclusion reached based on your observations and reasoning. (your opinion)

Observation vs. Inference

Observation vs. Inference

Making Observations There are 2 types: Qualitative Observations – A description using the 5 senses. Ex: Color, Odor, Taste, Sound, Texture Ex: The cat is black with white spots. Quantitative Observations – A description using number values. Ex: There are 15 mL of water in the graduated cylinder. Ex: The spider was 9 cm long. Ex: There are 5 birds in the sky. Qualities vs. Quantities L = Looks N = Numbers

Let’s Practice! The cheetah runs fast. Determine if the following observation is qualitative or quantitative: The cheetah runs fast. The Commack High School day ends at 2:25 PM. It is cold outside today. It is 10oC outside today.

Setting up experiments When you set up an experiment, you will need to determine the: Variable (being tested) Constants Control Group & Experimental Groups

Variables vs. Constants Variable – A factor that can be changed in an experiment by the scientist. There can be 2 types: Independent Variable – The scientist manipulates (controls/determines) this. The variable that “I” change. (tested) Dependent Variable – Depends on/Responds to the independent variable. The variable that changes based on what the scientist does. (result/measured)

Constants A factor that stays the same throughout the entire experiment. There will be many of these!

Let’s Practice! Worksheet

When Graphing…

When writing your hypothesis If we change our independent variable, then how will our dependent variable respond, because why. Ex: If I use the heater, then the room will become warmer, because the heater releases warm air. IV: Heater Use DV: Room Temperature

Control vs. Experimental Group Control Group – The group that does not get tested with the independent variable. Ex: Classroom of the same size with no heater. Experimental Group – The group that receives the independent variable. Ex: 3 Classrooms of the same size with heater turned up to 75 oC.

Let’s Practice! Worksheet

CONDUCTING AN EXPERIMENT

What you need… Valid Experiments are carried out properly so you are able to draw conclusions. When people make a claim, you should determine if the experiment is valid. If it is not, you should not value that claim. THINK to yourself: What is the evidence for this claim? Does the reason behind it make sense? Ex CLAIM: You can get washboard abs by doing 8 minutes of ab workouts a day.

Ways to Improve the Validity of Experiments Use a large sample size Conduct many trials Only test ONE VARIABLE (Independent Variable) at a time Use a control group for comparison Eliminate bias (The scientist influences the results to get a certain outcome) Only base conclusions on OBSERVED results

Problem/Question John watches his grandmother bake bread. She explains that the bread rises because yeast releases a gas as it feeds on sugar. John wonders “Does the amount of sugar used in the recipe affect the size of the bread loaf?”

He keeps all of his information on this topic in a journal. Background Research John researches the areas of baking and fermentation and tries to come up with a way to test his question. He keeps all of his information on this topic in a journal.

Formulate a Hypothesis After talking with his teacher and conducting further research, he comes up with a hypothesis. “If more sugar is added, then the bread will rise higher.”

Independent Variable The independent (manipulated) variable is a factor that’s intentionally varied by the experimenter. Ex: John is going to put 25 g, 50 g, 100 g, 250 g, and 500 g of sugar in each beaker.

In this case, it would be the size of the loaf of bread. Dependent Variable The dependent (responding) variable changes because of changes made to the independent variable. In this case, it would be the size of the loaf of bread.

She discusses with John how to determine the control group. Experiment His teacher helps him come up with a procedure, a list of needed materials. She discusses with John how to determine the control group.

Experiment - Control Group In a scientific experiment, the control group serves as the standard of comparison. Think of the control group as a “no treatment" group.

Experiment - Control Group The control group is exposed to the same conditions as the experimental group, except it is not exposed to the variable being tested. THINK QUESTION: Is this the IV or DV? All experiments should have a control group.

Experiment - Control Group Because his grandmother always used 50 g of sugar in her recipe, John is going to make no change in his control group, and use 50 g of sugar.

Experiment - Constants John’s teacher reminds him to keep all other factors the same so that any observed changes in the bread can be attributed to the differences in the amount of sugar. THINK QUESTION: What are some constants in John’s experiment?

Experiment - Constants They might include: Other ingredients to the bread recipe, oven used, rise time, brand of ingredients, cooking time, type of pan used, air temperature and humidity where the bread was rising, oven temperature, age of the yeast…

John is going to test each sugar variable 3 times. Experiment - Trials Trials refer to the amount of times John will repeat his experiment using the same conditions each round. John is going to test each sugar variable 3 times.

Collect and Analyze Results John comes up with a table he can use to record his data. He examines his data and notices that his control (50 g) worked the best in this experiment.

FORM & REPORT Conclusions John rejects his hypothesis. He tells his Grandmother that the bread does not rise higher when more sugar is added.

Now it’s time for you to try!