Scientific Questions = Testable Questions

The scientific method (Dr. OPHERC) is a way to gather evidence in order to develop a scientific explanation of phenomena.  After making interesting observations (O), we identify problems (P) and questions for investigation.  However, it is important that the questions we ask are  "testable".  Without a testable question to start our investigation, we won't be able to gather meaningful evidence.

What is a testable question?

A testable question asks something that can be measured and observed (phenomena) through experimentation.  In other words, a testable question can only be answered by gathering evidence.  If your question does not require collecting data (qualitative and quantitative observations), then your question is NOT "testable".

Another way to think about is in terms of a controlled experiment.  A testable question asks how one change (independent variable) has an effect on something else (dependent variable).

Testable questions examine cause and effect relationships.  In other words, testable questions look into how an independent variable (IV) affects a dependent variable (DV).

Below are some example testable question formats:

• How does            (IV)           affect          (DV)         ?
• What is the effect of            (IV)            on            (DV)          ?
• What effect does            (IV)            have on            (DV)          ?

Testable questions are not related to personal preference, moral values, the supernatural, or things that cannot be measured.  Just remember: Testable questions do not ask about things that are NOT considered to be phenomena!

How do you turn a topic into a testable question?

Now it is time that we learn how to develop our own testable questions so that we can begin designing our own controlled experiments!  It is important that we choose topics that are meaningful and of interest to us. Therefore, the next question is, how do we take a topic (that interests us) and turn it into a testable question for investigation?

1.  First, make two lists.

• List everything you can measure about your topic of interest.
  
• List everything that you can change/treat differently to your topic of interest.
  

Example Topic: Tomato Plants

• List everything you can measure about the tomato plant (DV): height of plant, number of tomatoes, color of tomatoes, water content of tomatoes, number of leaves, mass of tomatoes, density of tomatoes, depth of the roots, circumference of tomato, pH of the tomatoes, etc.
  
• List everything that you can change/treat differently to your tomato plant (IV): amount of sunshine, type of light, amount of soil, type of soil, amount of compost, type of compost, species of tomato plant, amount of water, temperature, humidity, number of seeds in the pot, type of pot, pH of the soil, pH of the water, type of water, etc.
  

The first list are possible dependent variables.  The second list are possible independent variables.

2.  Next, pick one item from each list that interests you most.
You are essentially picking one dependent variable and one independent variable.

Example:

• Water content of tomatoes = Dependent Variable
  
• Amount of water = Independent Variable
  

3.  Finally, choose an appropriate testable question format and fill in the blanks with the appropriate variables.

• How does            (IV)           affect          (DV)         ?
• What is the effect of            (IV)            on            (DV)          ?
• What effect does             (IV)               have on           (DV)             ?

Example:
What is the effect of the amount of water given to a tomato plant on the water content of tomatoes?

Watch the video below on how to write testable scientific questions for investigation!  

In-Class Activity
Answer the questions below using information from the blog post and video.  Write the question and answer in complete sentences.

1.  What is a testable question? (highlight your definition in BLUE)
2.  What is NOT a testable question?
3.  What are the two parts of a controlled experiment that are in every testable question?
4.  What are the 3 steps to turning a topic into a testable question?
5.  Write 3 more testable questions about the tomato plant by following the steps in question #4.
6.  Follow the steps for turning the topic "Cafeteria Pizza at MS 88" into a testable question.  Make sure to outline each of the 3 steps to get full credit.  

Scientific Explanations of Phenomena

A scientific explanation is the scientific way of explaining phenomena we observe by supporting a claim about what we observe with evidence and reasoning.  What are phenomena?  Phenomena are things, events, or circumstances that can be studied and observed.  Octopus mimicry, gravity, and global warming are all examples of phenomena.  We can study and observe these things, events, and circumstances using our five senses, and/or with scientific tools and technology.  

On the other hand, ghosts, UFOs, and Big Foot are not considered phenomena.  Only a select few people claim to have observed these things, but even the fanciest technology and equipment have yet to be able to study, much less detect, these things.  

Scientists do not develop scientific explanations of things that are not considered to be phenomena.  This is simply because we cannot gather evidence, which is a critical part of a scientific explanation. 

FINAL Scientific Explanation I: Is air matter?
Air is matter (claim). We found that the mass of the balloon increases each time we blew more air into it.  When the balloon had no air, it had a mass of 1.9 g.  When we blew the balloon to 35 cm, the mass went up to 2.1 g.  Finally, when we blew the balloon to 55 cm, the mass increased even more to 2.4 g (evidence).  According to Glencoe New York Science Grade 7 (pg.243), “Matter is anything that takes up space and has mass”.  Therefore, the increasing size of the balloon and mass show that air takes up space and has mass, which are the defining characteristics of matter (reasoning).

Scientific Explanation II: "Are the two liquids the same?"  

Claim:
Sometimes scientists make a claim (answer to the question at hand) about phenomena before collecting evidence through an experiment via observations and background research.  Other times, scientists collect as much evidence as possible first in order to make a valid claim.  In this case, we collected the evidence first.

Evidence:
In order to answer this question (make a claim), we first had to collect evidence.  Below are the procedure we used to gather evidence.

1.  Record as many qualitative observations of each liquid as you can.
2.  Measure and record the mass (with the unit) of liquid A and B.  
3.  Measure and record the volume (with the unit) of liquid A and B.  
4.   Calculate the density of liquid A and B by dividing the mass of each liquid by the volume of each liquid.  The unit is g/mL.  

Reasoning:
In order to make sense of our evidence to answer the question, "Are the two liquids the same?", we had to do background research to understand the unique properties of liquids.  According to Wikipedia.org, "different materials usually have different densities".  Furthermore, according to middleschoolchemistry.com, "“…each substance has its own density because of the atoms and molecules it is made from.”  

Therefore, since the density of the two liquids were different, we can make the claim that the two liquids are different.

FINAL Scientific Explanation II: Are the two liquids the same?
The two liquids are not the same (claim).  Although both liquids were clear, we found that the two liquids had different odors.  Liquid A had a harsh, burning odor, while liquid B had a more sour odor.  Furthermore, when we calculated the density of each liquid, we found that liquid A had a density of 0.8 g/mL, while liquid B had a density of 1.05 g/mL (evidence).  According to Wikipedia.org, "different materials usually have different densities".  Furthermore, according to middleschoolchemistry.com, "“…each substance has its own density because of the atoms and molecules it is made from.”  Therefore, since odor and density are properties unique to different materials, we know that the two liquids are different.

Conclusion: Scientists develop scientific explanations of phenomena
Scientists develop scientific explanations of phenomena.  This is because phenomena are things we can observe, study, and things of which we can collect evidence.  This coming school year, you will hear the word "phenomena" regularly.  When you hear about stories of ghosts and UFOs this coming Halloween, be a scientist and ask the story teller...  What is your evidence?  What is your reasoning?!  

Assignment
Answer the questions below in complete sentences.
1.  What are phenomena?
2.  What are two examples of things that are considered phenomena?  Why are they considered to be phenomena?
3.  What are two examples of things that are not considered to be phenomena?  Why are they NOT considered to be phenomena?
4.  Why don't scientists study things that are not phenomena?
5.  Are black holes considered to be phenomena?  Why or why not?  
6.  Do scientists always make a claim (hypothesis) before collecting evidence?  Explain.
7.  How do we know air is matter?
8.  How do we know the two liquids are NOT the same?
9.  Explain how background research helped us to develop our scientific explanations to the questions, "Is air matter?", and "Are the two liquids the same?".

Extension Question
10. Write 3 facts about black holes after watching the following video: http://www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.html