The Scientific Method

What is the Scientific Method?? The basic steps that scientists follow to uncover facts and solve scientific problems It’s a plan for solving a problem! Gathering, organizing, and communicating data

What are the steps? Make an Observation Ask a Question Do Background Research Develop a Hypothesis Experiment: Test your Hypothesis Analyze the Data Conclusion (report and share)

Step 1: Observation Everything starts out with an observation What is an observation? Anything you perceive with your senses Ex. The sun is bright. Sugar tastes sweet. Sandpaper feels rough.

What can you observe about these two fish in their tanks?

Step 2: Form a Question Ask a question based on your observations. Develop a question that can be solved through experimentation! Can you think of a question based on your observation of the two fish?

Step 2: Form A Question Does the size of a fish’s tank affect how big it grows? We observed that the fish with the bigger tank was larger than the fish with the smaller tank. Is this a coincidence?

Step 3: Do Background Research Research your subject. Collect the knowledge you need to know to perform your experiment. Your research will help you to form your hypothesis.

Step 4: Develop a Hypothesis What is a hypothesis? An educated prediction or the answer of a problem or question Based on research and prior knowledge

Step 4: Develop a Hypothesis A hypothesis should sound like this.. “I think ___________________ because __________________________.” “If ____________________, then ___________________ because ________________.” You can fill in the “because statement” using your background research!

Step 4: Forming a Hypothesis What is your hypothesis for our question about the fish? Question: Does the size of a fish’s tank affect how big it will grow? Remember to use “I think…. Because……” or “If…. Then… because…” Use our background research to justify your prediction!

Step 5: Experiment (Test your Hypothesis) What is an experiment? This is how you test your hypothesis. Develop a set of steps you can repeat that will allow you to observe and collect data to test your hypothesis.

Step 5: Testing your Hypothesis An experiment includes variables. A variable is a quantity that is measured or changed during the experiment. There are different kinds of variables: Independent variable Dependent variable Control Constant

Step 5: Testing your Hypothesis Independent variable: What you are changing in the experiment Dependent variable: the outcome caused by changing the independent variable (this is what will be measured) Control: The “normal group” used for comparison (If we were testing adding things to the fishes’ water, the control would be a fish tank with plain water) Constant: stays the same from one experiment to the next

Step 5: Testing your Hypothesis For our experiment… Some types of fish grow bigger than others. How should we deal with this? Use only one type of fish in our experiment. We are trying to see if the size of the fish tank affects how big the fish will grow. What should we change? What should we have different measurements for? The size of the fish tank What should change depending on the size of the fish tank? The size of the fish How can we measure the growth of the fish during their time in our tanks? Measure at the beginning, measure at the end

Step 5: Testing your Hypothesis Let’s identify the variables in our experiment. Independent variable: What are we changing in the experiment? The size of the tank Dependent variable: What will change depending on our independent variable? The size that the fish will grow to Constant: What will stay the same in every experiment? The type of fish we use

Step 6: Collect and Analyze the Data Observations, information, and data are collected from the experiment. Organize the data (measurements, observations) and perform any calculations needed Interpret the data you gathered from your experiment

Step 6: Collect and Analyze the Data Use your data to construct charts or graphs. You can use the charts or graphs to SEE trends in your data. Dependent Variable Independent Variable

Step 6: Collect and Analyze Data How would you graph the data from our fish experiment? 1. Identify the Independent Variable and place it on the x axis. 2. Identify the Dependent Variable and place it on the y axis. 3. Plan a scale for your graph. Label the graph. 4. Place points for each Independent Variable on its Dependent Variable measurement. 5. Draw a line to smoothly connect the points.

Step 6: Collect and Analyze Data Pretend that we collected these results from our fish experiment. Tank Size Fish Start Size Fish End Size Total Growth 1 L 10g 14g 4g 2 L 12g 18g 6g 3 L 11g 20g 9g 4 L 21g 5 L 13g 25g

Step 6: Collect and Analyze Data We can use our data to create a graph. Growth of Fish (g) Tank Size (L)

Step 6: Collect and Analyze Data What does this graph show us? Growth of Fish (g) Tank Size (L)

Step 7: Conclusion Does your data support your hypothesis? If YES… You just made a scientific discovery! If NO… Make a new hypothesis or revise your experiment and test again!

Step 7: Conclusion (and Sharing) Summarize your results and answer your question. Were there any possible sources of error? Maybe one of our fish got sick and couldn’t grow normally. Does your data support your hypothesis? Why or why not?

That’s all!