Variables
What is an independent variable?
The variable that is changed by the scientist.
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 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 the muscle cream, while SpongeBob's arms and back are lathered with the regular lotion.
What is the independent variable? What is the dependent variable?
IV: Muscle cream on Patrick
DV: Amount of weight lifted after 1st and 2nd weeks.
Name the steps in the scientific method
Purpose/ask a question
research
hypothesis
experimentation
analysis results, conclusion, publish If hypothesis is wrong, rewrite and retest until correct.
Mr. Nunley wants to strengthen the immune system of his fish. He has researched that blue light is calming for fish. He knows that he can observe fish health by how well their natural colors appear on their bodies. He sets up two tanks. One tank has blue lights while a second tank has white light. He records qualitative data of observing the color of his fish. He doesn't notice any color change in his fish between the two tanks. Using your knowledge of the scientific method, what should Mr. Nunley do now that his hypothesis is incorrect?
Rewrite the hypothesis and retest.
How do you write a hypothesis?
Using an IF/Then or IF/Then/Because statement
What is the independent variable directly related to in a cause and effect relationship?
Dependent Variable
Sponge Bob notices that his pal Gary is suffering from Slimtosis, which occurs when the shell develops a nasty slime and gives off a horrible odor. His friend Patrick tells him that rubbing seaweed on the shell is the perfect cure, while Sandy says that drinking Dr. Kelp will be a better cure. Sponge Bob decides to test this cure by rubbing Gary with seaweed for 1 week and having him drink Dr. Kelp. After a week of treatment, the slime is gone and Gary's shell smells better.
What should SpongBob's conclusion be?
Can't tell if Dr. Kelp works because he has two IVs: Dr. Kelp and rubbing of seaweed. Inconclusive.
To make sure it hasn't been done before and the question has already been answered.
Mr. Waleski is building an outdoor weight room on the side of his house. He wants to lay down a concrete foundation. He isn't sure which concrete can hold the most weight so he conducts an experiment using three different types of cement: one with pebbles, one with fine granules, and one with a mixture of both. He makes a small batch of each kind and puts them in a pie crust container to dry. He then gradually places his weights on top of each to see which one can hold the most weight. The last one to crack will be used for the foundation. List some constraints to this experiment that he would want to remain consistent?
Teacher determines answers that work.
What does the If, Then, and Because portions of the hypothesis in an experiment represent?
If-independent variable
Then-dependent variable
Because-Scientific reasoning
How does a scientist manipulate the independent variable in the control group?
He/She/They doesn't. The independent variable is not manipulated purposefully to serve as a basis of comparison for the experimental group.
Daily Double:
Patrick believes that fish eat food exposed to microwaves will become smarter and would be able to swim through a maze faster. He decides to perform an experiment by placing fish food in a microwave for 20 seconds. He has the fish swim through a maze and records the time it takes for each one to make it to the end. He feeds the special food to 10 fish and gives regular food to 10 others. After 1 week, he has the fish swim through the maze again and records the time for each.
What is the independent and dependent variables?
IV: Eating microwaved food
DV: How fast a fish swims
What happens if the results don't support the hypothesis?
Mrs. Zawacki wants to see what type of water will increase the chances of getting a sunburn. On one day she rubs fresh water on her skin and lays out in the sun for an hour and then uses qualitative data of touch to measure sunburn. She repeats this trial two more times with one day using saltwater and another day using mineral oil. She discovered that mineral oil left the worst sunburn. What would be a great example of a control for this experiment?
Teacher determines if answer provided is correct.
Daily Double:
What variables in an experiment do the x and y axis' represent?
y axis=dependent variable
x axis=independent variable
What is the IV and DV in the experiment below?
Which type of light helps plants do photosynthesis better: White light, Blue Light, or Red Light?
IV: Type of Light
DV: Amount of plant growth
Mr. Krabbs wants to make Bikini Bottoms a nicer place to live. He has created a new sauce that he thinks will reduce the production of body gas associated with eating crabby patties from the Krusty Krab. He recruits 100 customers with a history of gas problems. He has 50 of them (Group A) eat crabby patties with the new sauce. The other 50 (Group B) eat crabby patties with sauce that looks just like new sauce but is really just mixture of mayonnaise and food coloring. Both groups were told that they were getting the sauce that would reduce gas production. Two hours after eating the crabby patties, 30 customers in group A reported having fewer gas problems and 8 customers in group B reported having fewer gas problems.
What should Mr. Krabs' conclusion be?
Teacher Decision on answer.
Why is it impossible to have two independent variables?
Because you won't know what caused the dependent variable to change.
Ms. Hoy, Mrs. Beeler, and Ms. Shepard are trying to figure out the best writing program for students. On blue days they use Writer's Workshop and on orange days they use Writer's Rope. They plan to judge which one is better based on improvement of student writing samples after two months of writing. What is the dependent variable in this scenario?
Student improvement in their writing.
What are the five parts of a graph that must be there in order for it to be a graph?
title, labels for x and y axis', scales, and begins with "0".
In the Bubbles Lab: Name some examples of constants.
Temperature in the room, amount of bubble solution, type of table top, type of straw, etc.
In a typical scenario, Mr. Krabs creates a new breath mint with a secret ingredient to reduce bad breath. He gives one group of customers the new mint (group A) and another group a regular mint without the secret ingredient.
Write a hypothesis from this example using an IF/Then statement
John wants to learn gardening. He has been encouraged to use fertilizer because his soil around his house is mostly clay-based. He wants to see which fertilizer will help his plants grow the fastest. He sprinkles Hellman's fertilizer on one side of his house and Layman's fertilizer on the other. Over three weeks, he monitors plant growth.
What is the independent variable and dependent variable of this example?
IV: Type of fertilizer
DV: Rate of plant growth
Mrs. Zawacki wants to figure out which bugs the bearded dragons likes to eat the best. He usually eats mealworms. She puts her dragon on the floor and baits him with a mega-worm, dubi roach, and a cricket and times how fast it takes him to run to the bug. Whichever bug the dragon runs to the quickest is his favorite. Identify the independent and dependent variables, and control.
IV: Type of bug
DV: Speed of dragon
Control: Mealworm
John wanted to build a greenhouse. He noticed that some greenhouses use clear material while others use translucent material. He then build two greenhouses one with transparent siding, and the other with translucent siding. Over the course of two weeks, he measured temperature changes inside the greenhouse. He discovered that translucent material did a better job of raising temperature for plant growth in the greenhouse.
If John wanted to graph his data, how would he label the y-axis? How would he label the x-axis?
y-axis: Rate of Temperature Change (DV)
x-axis: Type of Siding Material (IV)