Scientific Method study guide for Friday, March 21

[Note: The videos shown in class on Thursday

are included at the bottom of this study guide.]

There is going to be a scientific method test on Friday, March 21. The study guide for this test is very similar to the study guide for the last test, but this one has more information.

For the test, students will need to understand the parts of an experiment. Here are the vocabulary terms.

independent variable = the variable that is purposely changed by the scientist in order to see if the dependent variable changes with the independent variable; you can also think of this as the difference in your groups. 

dependent variable = the variable observed and/or measured during the experiment to find out if it changes with the independent variable 

controlled variables = all the things that could change but the scientist keeps the same to prevent them from interfering with the experiment 

hypothesis = a prediction of what you will find in your experiment; a predicted answer to your scientific question; a hypothesis is usually stated as an if/then statement.
Important detail: A scientific hypothesis must be testable.

In our class experiment, we had the question, "Do 7th grade DRMS boys have better hand-eye coordination for throwing than 7th grade DRMS girls?"

Our hypothesis was, "If I compare the accuracy of 7^th grade DRMS males and females at throwing tennis balls into a trash can, then it will be found that males are more accurate than females."

Our independent variable was the gender of the people--boys vs girls. That's what we changed about the groups.

Our dependent variable was the number of baskets scored by each person. That is what we measured to see if it changed with the groups.

Our controlled variables included everyone using the same tennis balls, standing the same distance away, throwing at the same trash can, in the same room, having the same number of tries, etc.

Remember that the independent and dependent variables will be in the hypothesis. The "if" part contains the independent variable, and the "then" part contains the dependent variable. In our experiment, the "if" was comparing boys and girls, and the "then" was the number of baskets scored per person. You should be able to determine the independent and dependent variables by looking at the hypothesis.


Here are the questions that appeared on the last test:

Dr. Sarah Smith has a friend, Jessica, who only likes to eat yellow M&Ms. Dr. Smith tried to convince Jessica that all the M&Ms taste the same, but Jessica insists the yellow ones taste better. So, Dr. Smith decided to conduct an experiment. She found 20 volunteers. Each one was blindfolded and then given a bowl with M&Ms in it. Each bowl contained 5 yellow M&Ms, 5 blue M&Ms, and 5 orange M&Ms. Then, each volunteer was asked to take out one M&M at a time and try to identify its color by its taste. Dr. Smith recorded whether the volunteer was correct or incorrect. It turned out that volunteers correctly guessed the yellow M&Ms about 33% of the time.

What was Dr. Smith’s hypothesis?  Dr Smith's hypothesis was that all M&Ms taste the same. To put that into her if/then statement, it could be: If blindfolded volunteers are asked to identify the color of M&Ms by the taste, then it will be found that their chances of accurately identifying the color will be the same as if they were randomly guessing.


What is an independent variable in this experiment? The colors of M&Ms is the independent variable. That is the differences in the groups being compared.

What is a dependent variable in this experiment? The dependent variable is the volunteers' ability to accurately identify color by taste.
What is a controlled variable in this experiment? Some of the controlled variables are that all volunteers were blindfolded, asked the eat one M&M at a time, given the same number of M&Ms, etc.

Andrea, a student at Haines City IB school, wanted to know which shape was best for a wind turbine blade. Wind turbines have blades that spin in the wind and then use that spinning to generate electricity.

She did some online shopping for wind turbines and found that most (60%) had a simple propeller shape. About 20% had a corkscrew shape; she read that the corkscrew shape was better for keeping birds from crashing into the blades. The remaining 20% of turbines for sale had a more complicated shape known as the humpback. That shape is supposed to look a little like a humpback whale. Andrea decided to read some more about turbine blade design and she found out the most researchers believe the humpback shape is the best at catching wind and turning it into electricity. But, the humpback shape is the most expensive to build; that’s why it’s not as popular as the propeller design. Other researchers have found that the corkscrew shape is just as effective as the propeller, but it’s also more expensive to build.

Andrea decided to compare the three different blade shapes. She built her own turbines using metal. Each blade was made to be 1 foot long. She then placed the homemade windmill in front of a large fan, which she turned on to high. She counted how many times the blade turned in 1 minute.

What would have been the best hypothesis for Andrea to use?  If the propeller, corkscrew and humpback blade designed are compared, then it will be found that the humpback blade will spin more times per minute.


What is an independent variable in this experiment?  the blade design

What is a dependent variable in this experiment? the number of spins per minute

What is a controlled variable in this experiment? all blades were 1' long, and they were made from metal, the fan was on high, etc.

Finally, here are the last questions from the previous test. This study guide doesn't have the answers for this part. That way, you can use this to practice.

Tyler, another Haines City IB student, wanted to enter the school science fair. For her experiment, she decided to test various drinks and their ability to stain teeth. Of course, she didn’t want to actually stain people’s teeth, so she used eggs as a substitute. She read that egg shells are made of similar materials to human teeth, so egg shells are a good substitute in this kind of experiment. She also read that coffee is one of the worst drinks when it comes to staining teeth over time. Other researchers had compared coffee, tea and Coke, and they all found that coffee was the worst. Tyler decided to do something different in her experiment, though. She decided to compare coffee with lemonade, because she wondered if lemonade could turn people’s teeth yellow.

Experiment

To do her experiment, Tyler used 12 eggs. She placed 6 of them in 16oz cups, and then she filled those cups with fresh, hot coffee. She took the other 6 eggs and placed them in 16oz cups; then she filled those cups with nice, ice cold lemonade. She allowed all 12 eggs to sit in their cups for one day. Then, she took all the eggs out, dried them off, and compared their stains. She used a colorimeter (which measures color) to compare how dark the stains were on each egg. After analyzing her data, she found that coffee had stained the eggs more than lemonade. 

What would have been the best hypothesis for Tyler to use?

What is an independent variable in this experiment?
What is a dependent variable in this experiment?

What is a controlled variable in this experiment?
What is the biggest mistake Tyler made in the design of her experiment?

Here's another practice problem:

Billy Bob wanted to know if organic pesticide works better than artificial pesticide at preventing oleander caterpillars from attacking his oleander plant. After reading about other people's experiments, he learned that most researchers have found organic pesticides are less effective. So, he developed this hypothesis:
"If organic pesticides and artificial pesticides are compared in their ability to prevent oleander caterpillars from attacking oleander plants, then it will be found that oleander plants treated with organic pesticides will have more caterpillars than oleander plants treated with artificial pesticides."

What is the independent variable?
What is the dependent variable?
What are three controlled variables needed for this experiment?

Scientific Variables video

Parts of an Experiment video

Controlled Experiments video

Extra Credit due March 21

Here are two extra credit opportunities that are due on Fri, March 21. Don't forget that there's also a study guide for the test that will be on Friday. 

Click this link to read "The (kids') eyes have it." Then, answer the following questions on a paper that you will bring to class on Friday, March 21. The questions are worth 5 points each.

1. What was the independent variable?
2. What was the dependent variable?
3. What was one controlled variable?
4. How did scientists explain the conclusion?
5. Why were the results were surprising to some scientists?

Click the link to read the article, "Risk-taking linked to Ritalin." Then, write the answers to the following questions on a paper you will bring to class on the 21st.The questions are worth 5 points each.

1. What was the independent variable?
2. What was the dependent variable?
3. What was given to the control group?
4. What was given to the experimental group?
5. What were three controlled variables?
6. What was the conclusion?
7. Why is this research important?

 You can read more info on control groups and experimental groups at this link.

Scientific Method study guide for Friday, March 21

There is going to be a scientific method test on Friday, March 21. The study guide for this test is very similar to the study guide for the last test, but this one has more information.

For the test, students will need to understand the parts of an experiment. Here are the vocabulary terms.

independent variable = the variable that is purposely changed by the scientist in order to see if the dependent variable changes with the independent variable; you can also think of this as the difference in your groups. 

dependent variable = the variable observed and/or measured during the experiment to find out if it changes with the independent variable 

controlled variables = all the things that could change but the scientist keeps the same to prevent them from interfering with the experiment 

hypothesis = a prediction of what you will find in your experiment; a predicted answer to your scientific question; a hypothesis is usually stated as an if/then statement.
Important detail: A scientific hypothesis must be testable.

In our class experiment, we had the question, "Do 7th grade DRMS boys have better hand-eye coordination for throwing than 7th grade DRMS girls?"

Our hypothesis was, "If I compare the accuracy of 7^th grade DRMS males and females at throwing tennis balls into a trash can, then it will be found that males are more accurate than females."

Our independent variable was the gender of the people--boys vs girls. That's what we changed about the groups.

Our dependent variable was the number of baskets scored by each person. That is what we measured to see if it changed with the groups.

Our controlled variables included everyone using the same tennis balls, standing the same distance away, throwing at the same trash can, in the same room, having the same number of tries, etc.

Remember that the independent and dependent variables will be in the hypothesis. The "if" part contains the independent variable, and the "then" part contains the dependent variable. In our experiment, the "if" was comparing boys and girls, and the "then" was the number of baskets scored per person. You should be able to determine the independent and dependent variables by looking at the hypothesis.


Here are the questions that appeared on the last test:

Dr. Sarah Smith has a friend, Jessica, who only likes to eat yellow M&Ms. Dr. Smith tried to convince Jessica that all the M&Ms taste the same, but Jessica insists the yellow ones taste better. So, Dr. Smith decided to conduct an experiment. She found 20 volunteers. Each one was blindfolded and then given a bowl with M&Ms in it. Each bowl contained 5 yellow M&Ms, 5 blue M&Ms, and 5 orange M&Ms. Then, each volunteer was asked to take out one M&M at a time and try to identify its color by its taste. Dr. Smith recorded whether the volunteer was correct or incorrect. It turned out that volunteers correctly guessed the yellow M&Ms about 33% of the time.

What was Dr. Smith’s hypothesis?  Dr Smith's hypothesis was that all M&Ms taste the same. To put that into her if/then statement, it could be: If blindfolded volunteers are asked to identify the color of M&Ms by the taste, then it will be found that their chances of accurately identifying the color will be the same as if they were randomly guessing.


What is an independent variable in this experiment? The colors of M&Ms is the independent variable. That is the differences in the groups being compared.


What is a dependent variable in this experiment? The dependent variable is the volunteers' ability to accurately identify color by taste.

What is a controlled variable in this experiment? Some of the controlled variables are that all volunteers were blindfolded, asked the eat one M&M at a time, given the same number of M&Ms, etc.

Andrea, a student at Haines City IB school, wanted to know which shape was best for a wind turbine blade. Wind turbines have blades that spin in the wind and then use that spinning to generate electricity.

She did some online shopping for wind turbines and found that most (60%) had a simple propeller shape. About 20% had a corkscrew shape; she read that the corkscrew shape was better for keeping birds from crashing into the blades. The remaining 20% of turbines for sale had a more complicated shape known as the humpback. That shape is supposed to look a little like a humpback whale. Andrea decided to read some more about turbine blade design and she found out the most researchers believe the humpback shape is the best at catching wind and turning it into electricity. But, the humpback shape is the most expensive to build; that’s why it’s not as popular as the propeller design. Other researchers have found that the corkscrew shape is just as effective as the propeller, but it’s also more expensive to build.

Andrea decided to compare the three different blade shapes. She built her own turbines using metal. Each blade was made to be 1 foot long. She then placed the homemade windmill in front of a large fan, which she turned on to high. She counted how many times the blade turned in 1 minute.

What would have been the best hypothesis for Andrea to use?  If the propeller, corkscrew and humpback blade designed are compared, then it will be found that the humpback blade will spin more times per minute.


What is an independent variable in this experiment?  the blade design

What is a dependent variable in this experiment? the number of spins per minute

What is a controlled variable in this experiment? all blades were 1' long, and they were made from metal, the fan was on high, etc.

Finally, here are the last questions from the previous test. This study guide doesn't have the answers for this part. That way, you can use this to practice.

Tyler, another Haines City IB student, wanted to enter the school science fair. For her experiment, she decided to test various drinks and their ability to stain teeth. Of course, she didn’t want to actually stain people’s teeth, so she used eggs as a substitute. She read that egg shells are made of similar materials to human teeth, so egg shells are a good substitute in this kind of experiment. She also read that coffee is one of the worst drinks when it comes to staining teeth over time. Other researchers had compared coffee, tea and Coke, and they all found that coffee was the worst. Tyler decided to do something different in her experiment, though. She decided to compare coffee with lemonade, because she wondered if lemonade could turn people’s teeth yellow.

Experiment

To do her experiment, Tyler used 12 eggs. She placed 6 of them in 16oz cups, and then she filled those cups with fresh, hot coffee. She took the other 6 eggs and placed them in 16oz cups; then she filled those cups with nice, ice cold lemonade. She allowed all 12 eggs to sit in their cups for one day. Then, she took all the eggs out, dried them off, and compared their stains. She used a colorimeter (which measures color) to compare how dark the stains were on each egg. After analyzing her data, she found that coffee had stained the eggs more than lemonade. 

What would have been the best hypothesis for Tyler to use?


What is an independent variable in this experiment?

What is a dependent variable in this experiment?


What is a controlled variable in this experiment?

What is the biggest mistake Tyler made in the design of her experiment?

Here's another practice problem:

Billy Bob wanted to know if organic pesticide works better than artificial pesticide at preventing oleander caterpillars from attacking his oleander plant. After reading about other people's experiments, he learned that most researchers have found organic pesticides are less effective. So, he developed this hypothesis:
"If organic pesticides and artificial pesticides are compared in their ability to prevent oleander caterpillars from attacking oleander plants, then it will be found that oleander plants treated with organic pesticides will have more caterpillars than oleander plants treated with artificial pesticides."

What is the independent variable?

What is the dependent variable?

What are three controlled variables needed for this experiment?