Objective: Today we will So that we will be able to Design & carry out a maze experiment together So that we will be able to Design investigations using independent, dependent, and controlled variables. Design a control group for comparison, when appropriate.

On a post-it note, please list Bell Work: On a post-it note, please list the parts of the “Scientific Method.” Afterwards, have students share (could use rally robin with partner).

The “Scientific Method” Identify a question Gather information State a hypothesis Design and conduct an investigation 5. Collect and analyze data 6. Draw conclusions 7. Communicate results Discuss: As we get more sophisticated in our science, we think of these less as sequential steps and more as a possible stages that a project could be in. Flip to pg 17 in text. How is this different? More cyclical process that must undergo constant revision and may involve lots of dead ends and unsupported hypotheses before reaching an “answer” to our question.

Background Information: Maze studies have been used in psychology research since the early 1900’s as a way to measure an animal’s ability to learn and remember. How to insert meme into slideshow? http://www.memes.com/img/190162

Background Information: For example: Does getting a reward (like cheese!) help a rat learn faster? For more info about maze studies, check out www.ratbehavior.org/RatsAndMazes.htm

Today: We’re going to design & carry out a maze experiment together! Step 1: When I say “go,” complete the maze in front of you as fast as you can. Write your name and the time you finished on the top. Display a stopwatch on the board so that students can record their times. http://www.online-stopwatch.com/

Brainstorm What factors might affect how long it takes you to do a maze? Faster: Slower: With your table/partner, choose 1 factor to investigate. If students are feeling uncertain, they can choose one that we’ve brainstormed. If feeling more confident, can choose own variable.

Design Your Investigation: Please answer the questions in the first TWO columns to help you plan your investigation! 5 Minutes Fill in the first 2 columns in the first row together. Before changing any variables, we completed the maze once. We did this to see what our time would be under normal conditions so that we can COMPARE our experimental results to our results under normal conditions.

Carry Out Your Investigation: Carry out your investigation & record your results. (10 Minutes) State your conclusion in 1-2 sentences. (5 Minutes) Don’t write anything in the “analysis” section yet!

Control Run: Completing the maze under normal conditions (before we change any variables) is your “control run.” The Control Run (or Control Group) shows what would have happened under normal conditions, before any variables are changed. After the experiment, we can compare our experimental results to our controlled results to see if the changes we made in the experiment had any effect. Note: A control group is not always necessary.

Variables: Variable = Anything that can CHANGE in an experiment. Examples: What type/color pen we used The amount of noise in the room Which person completed the maze How difficult the maze was How long it took to complete Etc….

There are 3 Types of Variables: Independent Variable (IV) = The thing that the scientist changes. Dependent Variable (DV) = The thing that changes because of the IV. (This is almost always the thing that the scientist measures!) Controlled Variables (CV) = The things that the scientist keeps from changing/holds constant so that they don’t affect the results. What was the IV

Variables: What were your IV, DV, & CVs? Examples: What type/color pen we used The amount of noise in the room Which person completed the maze How difficult the maze was How long in took to complete Etc….

You should always have ONLY 1 IV and 1 DV because you are looking for a cause – effect relationship.

Hypothesis A possible explanation (or prediction) developed by the scientist that helps to guide his/her investigation. Example: Jocote Fences in Central America No, it doesn’t need to be in “if… then…” format! In the jocote investigation I told you about, we noticed that the jocote plants that were farmed still seemed to have a lot of diversity (there were different colors, sizes, types, etc). This is different than most farmed crops, like corn, that all tend to look pretty uniform compared to their wild ancestors. We hypothesized that the farmers were doing something in their farming practices to maintain the genetic diversity. Because we had thought about our hypothesis, we were on the look out for this farming practice when we were out collecting plants. We noticed that the farmers would take trees from the wild to build living fences around their property. They would then take trees from the fences to plant their farms. So, the living fences acted as storehouses of genetic diversity. If we hadn’t though through some of the possible explanations ahead of time, to create our hypothesis, we may have missed these important fences!

Analysis: Based on what you’ve just learned about designing a scientific investigation, write 2-3 sentences analyzing your investigation. Address questions like: How confident are you in your results? What would make you more/less confident? If you could redo your investigation, is there anything you would change about the design? What would a logical follow-up investigation be?

Analysis: By completing the same maze more than once, you introduced another variable, which likely affected the time required to complete the maze. What is that variable? Challenge: How would you eliminate this variable? Explain. You introduced the additional variable of exposure to the maze. The more times you complete a maze, the more quickly you will likely be able to complete it. So, we don’t know if your times were improving because of the IV you chose, or if you were just learning the maze. Eliminating this variable would be difficult because using a different maze each time would also introduce another variable – the different maze. Take away – the most important thing in designing an investigation is ensuring that we have only 1 IV and 1 DV so we can see that clear cause-effect relationship. If we have any additional variables, even by accident, then we cannot draw a sound conclusion. There are only a limited number of sound investigations that students could have planned given the materials provided – for example, how does the number of times you complete a maze affect your time?

Practice

Please underline the IV, circle the DV and list at least 3 CVs: Sandra is doing an experiment about fish. She wants to know if fish that live in polluted water have more harmful chemicals in their bodies. She sets up several different aquariums – some have polluted water and some have clean water. She puts one fish in each aquarium. After 1 year, she tests the fish to see how many harmful chemicals they have in their bodies. We will follow up tomorrow by repeating these practice problems and then also discussing if we have/need a control group & what it would look like.

Please underline the IV, circle the DV and list at least 3 CVs: Eric is studying athletes. He wants to know if athletes who take extra protein after lifting weights build more muscle than those who eat regularly. He asks the PRA football team to help. He has each player lift weights for 1 hour. Then, he has some of the players take protein while some of the players eat a regular dinner. He measures their muscle mass before and after to see whose muscles developed more. We will follow up tomorrow by repeating these practice problems and then also discussing if we have/need a control group & what it would look like.

Please underline the IV, circle the DV and list at least 3 CVs: Alex is studying bacteria. He wants to know what antibiotic kills the most bacteria. He has three different antibiotics. He puts the same amount of each on samples of bacteria. He then counts how many bacteria were killed in each sample. If running short on time, skip these practice problems today. We will follow up tomorrow by repeating these practice problems and then also discussing if we have/need a control group & what it would look like.

Closing: What’s wrong with Adrianna’s investigation? How would you fix it? Please use vocabulary from today’s lesson in your answer!

Homework: Finish IV, DV, CV practice problems if you did not finish during class today. OPTIONAL