Scientific Inquiry, Reflection and Social Implications UNIT TWO Scientific Inquiry, Reflection and Social Implications

SCIENTIFIC METHOD Q: What is the scientific method? A: The scientific method is a way to ask and answer scientific questions by making observations and doing experiments following a series of steps. Scientists use this method to search for cause and effect relationships in nature.

SCIENTIFIC METHOD Q: What are the steps of the scientific method? A: The steps of the scientific method are:

SCIENTIFIC METHOD 1. Ask a Question: The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where? The question must be about something that can be measured, preferably with a number.

SCIENTIFIC METHOD 2. Do Background Research: Use the library and internet to do research. Find out about previous attempts by other scientists to answer your question. Determine the best way to go about answering your question.

SCIENTIFIC METHOD 3. Construct a Hypothesis: A hypothesis is an educated guess about how things work. The hypothesis should be written in the following format: “If __(I do this)__, then __(this)__ will happen.” It must be stated in a way that can easily be measured and in a way to help answer the original question.

SCIENTIFIC METHOD 4. Test the Hypothesis with an Experiment: The experiment tests whether the hypothesis is true or false. It’s important for the experiment to be a fair test – be sure that only one factor is changed at a time while keeping all other conditions the same. This way, scientists can see how changes to one item causes something else to change. The experiment should also be repeated several times to make sure the first results weren’t just an accident.

SCIENTIFIC METHOD 5. Analyze the Data and Draw a Conclusion: Once the experiment is complete, collect the measurements and analyze them to see if the hypothesis is true or false. If the hypothesis is false, construct a new hypothesis and start the entire process of the scientific method over again. Even if the hypothesis is true, the scientist may want to test it again in a new way.

SCIENTIFIC METHOD 6. Communicate the Results: Professional scientists do this by publishing their final reports in a scientific journal or presenting their results at a scientific meeting.

SCIENTIFIC METHOD Note: Even though this process is shown as a series of steps, new information or thinking may cause a scientist to back-up and repeat steps at any point during the process.

SCIENTIFIC METHOD Q: How is a scientific experiment designed? A: A scientific experiment consists of two parts:

SCIENTIFIC METHOD 1. Experimental Factors: The parts of the experiment that change. Also called variables. A good experiment tests the effect of only one variable at a time.

SCIENTIFIC METHOD There are two types of variables in an experiment: a) Independent Variable: The variable that is manipulated by the scientist. Can be determined by asking yourself, “What am I changing in this experiment to produce a result?”

SCIENTIFIC METHOD b) Dependent Variable: The variable that changes because of the change in the independent variable. Can be determined by asking yourself, “What am I observing as I change the independent variable?”

SCIENTIFIC METHOD 2. Standardized Variables: Some parts of the experiment will stay the same. You may have many standardized variables in one experiment. Can be determined by asking yourself, “What am I keeping the same in this experiment?” One group will also be known as the control group. This group does not receive the independent variable Used to compare results to show that the independent variable had an effect

SCIENTIFIC METHOD Practice Problem #10: Identify the independent variable, dependent variable, and some standardized variables in the following experiment: A scientist varies the amount of water he gives to his tomato plants to see how it will affect their growth.

SCIENTIFIC METHOD Practice Problem #11: Identify the independent variable, dependent variable, and some standardized variables in the following experiment: A scientist measures how much water evaporates over time in different temperatures.  

SCIENTIFIC METHOD Practice Problem #12: Homer notices that his shower is covered in a strange green slime. His friend, Barney, tells him that coconut juice will get rid of the green slime. Homer decides to check this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with plain water. After 3 days of “treatment” there is no change in the appearance of the green slime on either side of the shower. 

SCIENTIFIC METHOD Practice Problem #12: What is being tested? What is the control setup? What is the experimental setup? What should Homer’s conclusion be?

SCIENTIFIC METHOD Practice Problem #13: Bart believes that mice exposed to microwaves will become extra strong (or perhaps he’s been reading too much Radioactive Man). He decides to perform this experiment by exposing 10 mice to microwaves for 10 seconds. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8 out of 10 microwaved mice were able to push the block away. 7 out of 10 non-microwaved mice were able to do the same.

SCIENTIFIC METHOD Practice Problem #13: What is being tested? What is the control setup? What is the experimental setup? What are some standardized variables? What should Bart’s conclusion be?

SCIENTIFIC METHOD Q: Can all questions be solved using the scientific method? A: No. In order to be solved using the scientific method, the question must involve something that can be proven through scientific experimentation with measurable dependent variables. You cannot design a scientific experiment to measure opinions, thoughts, beliefs, or other non-measurable variables and therefore questions involving these factors cannot be answered using the scientific method.

SCIENTIFIC METHOD Practice Problem #14: Decide whether or not the following questions can be answered using the scientific method. 1. Is the acceleration due to gravity really 9.8 m/s2? 2. Is water made of hydrogen and oxygen atoms? 3. Are Twix bars better than Snickers bars? 4. Are Great Danes happier dogs than Poodles? 5. Do people act crazy during full moons? 6. Do small cars get better gas mileage than SUVs? 7. Does candy make kids happy? 8. Do anteaters eat more ants when it is sunny?

SCIENTIFIC METHOD Q: What is the difference between a hypothesis, a scientific theory, and a scientific law? A: We already know that a hypothesis is an educated guess about how things work. Hypotheses require further testing to be proven true. Ex: My locker won’t open because I’m not using the correct combination.

SCIENTIFIC METHOD A scientific theory is a possible explanation about the way things work that has been tested. A hypothesis becomes a scientific theory after repeated testing has proven it true. Scientists are able to make predictions based on theories. Ex: Eating a high fat diet will result in high cholesterol.

SCIENTIFIC METHOD A scientific law is a repeated observation about nature. Scientific theories become scientific laws after they have been repeatedly tested and proven true. Ex: Newton’s 1st Law of Motion: For every action there is an equal and opposite reaction.

DATA ANALYSIS / GRAPHING Q: Why do we use graphs in science? A: Graphs are visual representations of the results of our scientific experiments. Using graphs to analyze data allows us to find patterns and relationships in data that would otherwise be difficult, if not impossible, to interpret.

DATA ANALYSIS / GRAPHING Q: Which types of graphs are we most likely to use in science? A: There are three types of graphs you are most likely to use in science. These are:

DATA ANALYSIS / GRAPHING 1. Line Graphs: Line graphs are used to show data that changes for only one item.

DATA ANALYSIS / GRAPHING Practice Problem #15: Answer the following questions using the line graph: Approximately how much hydrogen had been produced after 90 seconds had elapsed? How much time had elapsed when 117 mL of hydrogen had been produced?

DATA ANALYSIS / GRAPHING 2. Bar Graphs: Bar graphs are used when we want to compare data for several different items or events.

DATA ANALYSIS / GRAPHING Practice Problem #16: Answer the following questions using the bar graph: What is the approximate melting temperature of lead? Which metal has a melting temperature of approximately 1800 K?

DATA ANALYSIS / GRAPHING 3. Pie Charts: Pie charts are used when we want to see how the parts of something add up to 100% of the data. Pie charts are usually round and contain percentages.

DATA ANALYSIS / GRAPHING Practice Problem #17: Answer the following questions using the pie chart: Which element makes up 48% of calcite? What percentage of calcite is made up of carbon?

DATA ANALYSIS / GRAPHING Q: What are some tips for drawing good graphs and charts? A: For a great graph, make sure to: Choose the right type of graph for your data. Use graph paper. Only draw one graph per sheet of paper. Use a ruler for all straight lines. Draw in dark colors.

DATA ANALYSIS / GRAPHING Be neat. Title your graph. Label the x and y axes on line and bar graphs, including units of measure. Use different colors on bar graphs and pie charts if possible. Always put the independent variable on the x axis.

DATA ANALYSIS / GRAPHING Practice Problem #18: Draw a graph or chart using the following data showing how mass changes as temperature changes:

DATA ANALYSIS / GRAPHING Practice Problem #19: Draw a graph or chart using the following data that shows the favorite colors of a first grade class:

DATA ANALYSIS / GRAPHING Practice Problem #20: Draw a graph or chart using the following data that shows the % color distribution of a bag of M&Ms: