As we have learned in science class, most of our transportation is powered by fossil fuels.  When fossil fuels are burned, harmful greenhouse gases and pollutants are placed in the air.  Fossil fuels are considered to be non-renewable sources of energy, because they come from the remains of living things more than 300 million years ago that can in no way be replenished at the rate at which we humans are using them!  Therefore, we designed experiments to determine how best to propel rockets using Alka-Seltzer + water as a model of an alternative and renewable source of energy.

Before designing our experiments, we made some observations of other chemical reactions to get a better sense of how to design our own experiments.

As with every controlled investigation, we only change one variable in order to observe the effect(s) of that one change. Think back: What was the ONE variable that your group decided to change to the Alka Seltzer + water chemical reaction?  What is another way to describe the ONE variable that a scientist changes in an experiment?  What is another way to describe what the scientist measures?

Each group only changed one variable in order to see the effect(s) of that one change.  Some groups changed the temperature of the water or the amount of water, while other groups changed the size of the Alka-Seltzer tablet.  The group above changed the temperature of the water, and predicted that the hotter water would dissolve the tablet faster.

As a scientific community, we shared our group's results. Through our first round of experimentation, we learned that increasing the temperature, increasing the amount/volume of water, and crushing the Alka-Seltzer tablet all decreased the amount of time it took for the Alka-Seltzer to dissolve (for the chemical reaction to occur).

Before designing our rockets, we took a break and visited the animals!  What was your favorite animal at the Environmental Study Center?

After experimenting to better understand how the size of Alka-Seltzer, temperature and volume/amount of water affect the speed of the chemical reaction, each group picked one variable (= independent variable) to change to their Alka-Seltzer powered rocket to get the rocket that can propel the highest.  Most groups changed the temperature or size of the Alka Seltzer.  Do you remember which group had the highest rocket propulsion?  Do you remember this group's independent variable?

Last but most certainly not least, we learned that there is no such thing as failure in science.  There is also no such thing as an "incorrect" hypothesis, because the whole point of testing a hypothesis is to learn something new (and learning something new is never wrong/right/correct/incorrect).  Instead, we say that our hypothesis was "not supported" and reflect on the process and possible limitations that occurred in the planning/design and execution of the experiment, and also evaluate and possibly re-think our original hypothesis!

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.  

What is a controlled experiment?

A controlled experiment is an experiment that is conducted under a setting that is “controlled” by the scientist with the least possible influence from outside factors.  A controlled experiment compares an experimental group with a control group in the exact same conditions with the one exception of a special/different treatment given to the experimental group. 

The control group represents the "normal", "standard" or untreated condition.  The experimental group is the one part of the experiment that is changed/manipulated (given different treatment).  The constants are everything else you keep the same to ensure a fair test.

Francesco Redi's Controlled Experiment: Do maggots (young flies) come from rotting meat?

To better understand controlled experiments, let's look at Francesco Redi's famous controlled experiment on maggots and meat as an example.  Francesco wanted to find the answer to the question, "Do maggots (flies) come from rotting meat?".  This may seem like a really silly question, but in Francesco Redi's day (1600s), people actually believed that flies and maggots were generated spontaneously from meat.   Take a look at Redi's experiment below.

Homework

Watch the video below on a controlled experiment studying the effect of ozone on plants  Then answer the questions in your science notebook in complete sentences.

1.  What was the question the scientists were trying to answer through this controlled experiment?
2.  How were all of the plants treated the same?
3.  What is a variable?
4.  What is the variable (one thing changed) in this experiment?
5.  What was the control/control group in this experiment?
6.  What is a control/control group?
7.  What do the scientists measure/record everyday in this experiment?
8.  Why do you think it is important that scientists only test one variable in an experiment?

Extra Credit:

Watch the video of how students set up a controlled experiment to investigate the effect of mirrors on dolphin behavior: http://vitalny.pbslearningmedia.org/resource/737ed8f2-10bb-484e-9b75-e3f19a91f3a4/dolphin-dive-05-test/
Then answer the questions below.

1.  What was the control test/group in the dolphin experiment?
2.  What was the experimental group in the dolphin experiment?
3.  How do you think the students could have improved their experiment?

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

Scientific Method = Gathering Evidence

Last week, we learned that the Scientific Method is an organized method used by scientists to find and gather evidence (data) to support a claim (argument) about what the scientist observes.  There are many versions of the scientific method, but all versions of the scientific method involve trying to answer a specific question, and experimenting to find the answer.

The version of the scientific method that we will use in my class was given to me by my dear friend, Dr. OPHERC:

• Observation: The observation is simply any information gathered using the senses or an instrument.  A scientific investigation begins with an interesting observation in the world that generates questions that can be tested.

• Problem/Question: The problem/question is the specific question the scientist will attempt to answer through experimentation.

• Hypothesis: The hypothesis is the claim of the scientist, or an educated guess about the answer to the problem/question.  A hypothesis is based on sufficient observations, prior knowledge, and background research.  

• Experiment: The experiment is when the scientist actually tests his/her hypothesis for supporting evidence using detailed procedures, appropriate materials, and scientific measuring tools.  During the experiment, the scientist records all of his/her qualitative and quantitative observations.

• Results: The results are all of evidence (the qualitative and quantitative observations) gathered throughout the experiment.  The results are often displayed in tables, charts, and graphs for further studying. 

• Conclusion: The conclusion is the reasoning of the scientist that explains the meaning or significance of the results.  In the conclusion, the scientist links the evidence from the experiment back to the original claim (hypothesis).     

Scientific Explanation = Goal of a Scientist

During the first week of school, we learned that science is a way to develop explanations for what we observe, using the evidence we gather through our own experiments, and through the experiments of other scientists.  A scientific explanation, so to speak, is the scientific way of explaining what we observe in the world (and outside of the world, too!).  A scientific explanation is essentially a claim (about what a scientist observes/observed phenomena) that is supported with evidence and reasoning.  
The goal of a scientist is to develop scientific explanations to share with the scientific community, and the purpose scientific method is to gather the "evidence" component of the scientific explanation.  

But what is a claim?  What is evidence?  And what is reasoning?!  These components of a scientific explanation (C.E.R.) have been outlined below.

C.E.R. = Parts of a Scientific Explanation

• Claim: a conclusion that attempts to answer/address a testable scientific question. 
• Evidence: appropriate and sufficient data from an experiment, other scientists' experiments, reading material, and/or other observations that support the claim.  
• Reasoning: a justification that links the claim and evidence that incorporates appropriate and sufficient scientific principles; requires background research.  

Connecting the Scientific Method with C.E.R.

Last week, we performed an experiment to gather evidence in order to develop a scientific explanation. The question we addressed was, "What is the most common color in a 2.17 oz Original Fruit bag of Skittles?"

Below is an outline of how we gathered our evidence via the Dr. OPHERC.  We will use class 711's data for our example.

1.  The scientific method began with an observation.

Observation: There are five different colors in a bag of skittles - red, yellow, orange, green, purple.  Every time I eat a bag of skittles, the frequency (how many) of each color seems to be different.  

2.  This observation inspired, or led to, a question for investigation.

Problem/Question: What is the most common color in a 2.17 oz "Original Fruit" bag of Skittles?  

3.  We made a tentative claim (hypothesis) to test, based on our observations, background research, and prior knowledge.

Hypothesis: If purple is the most popular color of Skittles, then it will be the most common color in a 2.17 oz bag because the makers of Skittles will likely accommodate the preference of the consumers.  Furthermore, according to Skittles.com, green should make up 19.7% of a 2.17 oz bag, yellow should make up 19.5% of a 2.17 oz bag, orange should make up 20.2% of a 2.17 oz bag, red should make up 20% of a 2.17 oz bag, and purple should make up 20.6% of a 2.17 oz bag. 

4.  We then tested our hypothesis through an experiment to gather evidence.

Experimental Procedure:
1.  Open the bag of Skittles onto your sheet of paper towel.
2.  Group your Skittles according to color. 
3.  Count how many of each color are present in your group’s bag and record this info in table 1.   
4.  Analyze your data by creating a bar graph on Table 2.
5.  Make sure to label the graph showing colors and numbers of Skittles. 
6.  Form a conclusion.  State whether your hypothesis was correct or incorrect and why. 

5.  Next, we graphed all of our data (evidence).

Results:
Average number of red (class 711): 11.5 pieces
Average number of yellow (class 711): 13.3 pieces
Average number of orange (class 711): 10.2 pieces
Average number of green (class  711): 13.5 pieces
Average number of purple (class 711): 10.2 pieces

6.  We then made a conclusion by determining whether or not the evidence gathered supported our original claim.  The conclusion is essentially our reasoning.  The conclusion addresses our original claim (was it correct?  incorrect?), provides our evidence, and links our evidence back to our original claim.

Conclusion: My hypothesis was not supported through this experiment because I predicted that purple would be the most common color, and my results show that green is the most common color in this experiment.  The average total number of candies in class 711 was 58.6 pieces.  There was an average of 10.2 red candies, 13.3 yellow candies, 10.2 orange candies, 13.5 green candies, and 10.2 purple candies in a 2.17 oz bag.  Class 711's results were different from class 711, 714, 715, and 716. My next step is to average the data from all four classes.  Since every class has a different average frequency of colors, the results do not provide enough evidence to support or oppose my claim that purple is the most common color of skittles in a 2.17 oz bag.  Furthermore, since Skittles.com states that green should make up 19.7% of a 2.17 oz bag, yellow should make up 19.5% of a 2.17 oz bag, orange should make up 20.2% of a 2.17 oz bag, red should make up 20% of a 2.17 oz bag, and purple should make up 20.6% of a 2.17 oz bag, it is important that we increase our sample size in order to have a fair test.

Homework:

Answer the following questions in your science notebook.  Write the questions AND answer in complete sentences.

1.  Why do scientists use the scientific method?
2.  What is a scientific explanation according to this article?  Cite your evidence.
3.  How is the "reasoning" in a scientific explanation related to the claim and evidence?  Explain.
4.  According to this blog post, a claim is a conclusion that attempts to answer/address a testable scientific question.  What is another way to define claim?
5.  According to this blog post, evidence is appropriate and sufficient data from an experiment, other scientists' experiments, reading material, and/or other observations that support the claim.  What is another way to define evidence?
6.  Were we able to gather enough evidence through our Skittles experiment to support a claim that a particular color is the most common in a 2.17 oz bag of "Original Fruit" Skittles? Explain.
7.  Using the scientific method does not always provide the necessary evidence to support the claim (hypothesis) of the scientist.  What do you think a scientist should do in the case that the evidence does not support the claim (hypothesis)?  Explain what you think should be the next steps for the scientist.

Due: Monday, October 21, 2013.