Scientific Method and Experimental Design

Transcription

1 Biology Ms. Ye Name Date Block Scientific Method and Experimental Design

2 Video Notes: bit.ly/1lxjcb1 The scientific method is a process that is meant to produce to answer a Simplified example of how you might apply the scientific method to your life: Example from video Step in Scientific Method Woke up and couldn t find cell phone Think about the last time you had your phone Phone could be in the pants you wore yesterday Check your pants from yesterday Did not find cell phone in your pants Think about what else you did yesterday Cell phone might be in backpack Check backpack Find cell phone Tell friends the good news More details: A hypothesis is a and may be in if/then form. o Ex: If gummy bears are placed in water for 24 hrs, then they will swell to over twice their original size. Experiments may collect two types of data/observations: 1. (smell, color, appearance, etc) Ex: soft, yellow, shiny 2. (numerical information) Ex: 25 cm, 2.3 grams

3 Every experiment has two types of variables: 1. : The thing I (the scientist) change 2. : The thing I measure/am looking for in the experiment. o Example from Gummy Bear Experiment: Independent Variable Placement in Water (I the scientist have control over that) Dependent Variable Size of Gummy Bear (I do not have control over how big the gummy bears will get. This is something I measure. And two groups: 1. : has one independent variable altered 2. : all other groups are compared to this (this is the normal group) o Example from Gummy Bear Experiment: Experimental Group Bears in Water (these bears had one thing changed to them) Control Group Dry Bears (these are how gummy bears normally are) Additional Information: Because you only change one variable at a time during an experiment, all experiments also have constants = Patterns in Data: When appropriate, data can be plotted as a scatterplot and a trend (pattern or relationship) may be observed between the two variables o Direct Relationship= o Inverse Relationship= as one variable, as one variable, the other variable the other variable

4 A law tells us ; often has a formula o Ex: law of gravity, Boyles law A theory tells us o Ex: atomic theory, cell theory *A theory a law!* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Scenario 1: 1. In 1 2 sentences, summarize the purpose of this experiment. 2. What was Mr. Krabs hypothesis? 3. What is the independent variable in this experiment? 4. What is the dependent variable? 5. Which people are in the control group? 6. Were there any variables held constant in this experiment? 7. What should Mr. Krabs conclusion be? 8. Why do you think 10 people in group B reported feeling better?

5 Scenario 2: 1. What is the scientific question being explored in this experiment? 2. What is the independent variable in this experiment? 3. What is the dependent variable? 4. Which person is the control group? 5. Were there any variables that were held constant in this experiment? 6. What should Larry s conclusion be?

6 Scenario 3: Explain how SpongeBob could improve his experiment? Explain using the vocabulary we went through in the notes. Scenario 4: Analyze the data in the chart and determine whether or not the Super Snail Snacks created smarter snails. What else should be done to determine the effect of the snacks? Explain using the vocabulary we went through in the notes.

7 Reaction Timer Activity Biology Name Date Block Pre lab Questions: Remember: The Independent variable is the one I (the scientist) can easily/directly change. The Dependent variable is what I measure/the data I collect during an experiment. Ex: An experiment is done to see if the starting temperature of an oven affects how high a cake rises. IV: starting temperature of the oven (because I can easily change that). DV: how high the cake rises (this depends on the change in the IV, it is what I am measuring.) For the following situations, list the independent variable and dependent variable. 1. A study was done to find if different tire treads affect the braking distance of a car. IV: DV: 2. Students measured the temperature of the water at different depths in Lake Skywalker and found that the temperature varied. IV: DV: 3. A student wanted to test how the mass of a paper airplane affected the distance it would fly. Paper clips were added before each test flight. As each paper clip was added, the plane was tested to determine how far it would fly. IV: DV: **Show your teacher the answers to your prelab questions now. You MUST get this checked before you continue!**

8 Instructions: You are interested in testing factors that affect how far a ruler will drop before one person can grab it as another person drops the ruler through his or her fingers. In this experiment, you will be testing how using your dominant hand compares to using your nondominant hand. Each person in your group will serve as one trial in each condition (so you should have at least three trials in each condition). Problem Statement: Is the reaction time for your non dominant hand faster, the same or slower than your dominant hand? Hypothesis: If the reaction time for both the dominant hand and non dominant hand are tested, then. Procedure: 1. Have one partner hold the ruler vertically while the other holds his or her thumb and pointer finger from his or her dominant hand at the bottom of the ruler ( starting position ) ready to catch the ruler when it is dropped. 2. Partner 2 should drop the ruler without warning and partner 1 tries to catch it as quickly as possible with his/her dominant hand. 3. Observe where the ruler was caught (use the mark closest to the bottom of the thumb). Record the number. *Make sure to include units along with the recorded number!* 4. Repeat steps 1 3 with the partner s non dominant hand. 5. Repeat steps 1 4 two more times (once with each person in your group) and find the average. *Make sure to show your work for finding the average!* Data: Dominant Hand Trial # Average (show your work!) Reaction Time (include units!) Non Dominant Hand Trial # Reaction Time (include units!) Average (show your work!)

9 Questions: 1. What was the independent variable in this activity? Explain. 2. What was the dependent variable in this activity? Explain. 3. What were some variables that were held constant (at least 2)? 4. Which trial would you consider your control group? Why? 5. Based on your group s results, what should your conclusion be? Please support your response using the data you collected.

10 Scenarios to Print Scenario 1:Krusty Krabs Breath Mints Mr. Krabs created a secret ingredient for a breath mint that he thinks will cure the bad breath people get from eating crabby patties at the Krusty Krab. He asked 100 customers with a history of bad breath to try his new breath mint. He had 50 customers (Group A) eat a breath mint after they finished eating a crabby patty. The other 50 (Group B) also received a breath mint after they finished the sandwich, however, it was just a regular breath mint and did not have the secret ingredient. Both groups were told that they were getting the breath mint that would cure their bad breath. Two hours after eating the crabby patties, thirty customers in Group A and ten customers in Group B reported having better breath than they normally had after eating crabby patties. Scenario 2: Marshmallow Muscles: Larry was told that a certain muscle cream was the newest best thing on the market and claims to double a person s muscle power when used as part of a muscle building workout. Interested in this product, he buys the special muscle cream and recruits Patrick and SpongeBob to help him with an experiment. Larry develops a special marshmallow weight lifting program for Patrick and SpongeBob. He meets with them once every day for a period of 2 weeks and keeps track of their results. Before each session Patrick s arms and back are lathered in 2 pumps of the muscle cream, while Sponge Bob s arms and back are lathered with 2 pumps of the regular lotion. The results are shown in the table below.

11 Scenario 3: Flower Power SpongeBob loves to garden and wants to grow lots of pink flowers for his pal Sandy. He bought a special Flower Power fertilizer to see if will help plants produce more flowers. He plants two plants of the same size in separate containers with the same amount of potting soil. He places one plant in a sunny window and waters it every day with fertilized water. He places the other plant on a shelf in a closet and waters it with plain water every other day. Scenario 4: Super Snails Gary is not the smartest snail in Bikini Bottom and believes he can improve his brain power by eating Super Snail Snacks. In order to test his hypothesis, he recruits SpongeBob and several snail friends to help him with the experiment. The snails ate one snack with each meal every day for three weeks. SpongeBob created a test and gave it to the snails before they started eating the snacks as well as after three weeks.