What's the Problem?
A researcher is testing the effect of adding salt to a sample of blood cells. To the control group, he added 20 milligrams (mg) of salt, to the experimental group #1, 40 mg of salt were added.
The Control Group should not have any salt added.
A student wants to test how different amounts of sunlight affect plant growth. What is the independent variable?
The amount of sunlight the plants receive
Qualitative or Quantitative? : The foam rose by 20ml.
Quantitative
Students test if the type of liquid (water, soda, juice) affects how fast seeds germinate. What should they keep constant?
Amount of liquid given, location of seeds, sunlight on seeds, etc
A marine biologist is studying a species of sea turtle for the effect of different types of food on their weight. The marine biologist identified her independent variable as the change in weight of the turtle and the dependent variable as the different versions of test food. What's the problem?
She switched her IV and DV.
A scientist tests if music affects how fast hamsters run on a wheel. What should the scientist measure as the dependent variable?
Speed of hamsters
What goes in the "if" part of a hypothesis?
The IV
A group of students gathers their materials for the lab and notes they have 40 ml of blue solution and 2 white tablets. Is this an observation of Exerpimental DESIGN or is it DATA?
Design!
Mr. Jones wants to see which snake food - mouse or rat - helps Spike and his buddy Spock maintain their weight better. For 2 weeks Spike is at Mr. Jones’ house. He is getting 2 mice, a bowl full of crickets each morning and a helping of ground beef as well as 10 ml of reptile supplement each day. Spock is at school and is getting a one small rat once a week. Their weight will be compared after 2 weeks.
Too many things that aren't being held constant. Only thing that should be different is the mouse or the rat.
Students test if the type of liquid (water, soda, juice) affects how fast seeds germinate. What is the IV?
The type of liquid
What goes in the "then" part of a hypothesis?
The DV
A group of students is observing pillbugs in a choice chamber. As the experiment progresses they count 10 pillbugs on the side of the chamber with the disco light in it. Is this an observation of experimental DESIGN or is it DATA?
Data!
Which vocab word identifies the factors that should be kept the same between the control group and the experimental group ?
Constants
A teacher sets up two fish tanks: one with fertilizer added and one without. Give a possible hypothesis for this experiment.
If _________, then __________. (answers vary)
Name the snake and both turtles in our classroom.
Spike
Crush
Squirt
Researchers are observing the effect of adding growth hormones to oak trees. What is one example of QUALITATIVE data and one example of QUANTITATIVE data they could collect?
Answers may vary!
Qualitative = descriptive
Quantitative = numerical
Krusty the clown was told that a certain itching powder was the newest best thing on the market. Interested in the product, he buys the itching powder and tests it by comparing it to the original version. Subject A is sprinkled with the original itching powder and another test subject, Subject B, is sprinkled with the NEW itching powder. Krusty sends the subjects home and goes to sleep. The next day Krusty decides to stick with the original itching powder because he claims to not know which one worked more effectively. What's the problem?
He never collected data to see what the effect of the itching powder was. There is no DV beind measured.
A Maine South Cross Country member is testing out a new pair of shoes to see if it lowers her race time at the next meet. What is the DV?
A pharamicist set up a study to determine whether Vitamin C could reduce cold symptoms. 10 volunteers were split into two equal groups. For two weeks, members of Group 1 took 1 tablet of the Vitamin C. Group 2 took a placebo (a sugar pill that does not contain the supplement). At the end of the two-week period, the pharmacist exposed the volunteers to germy preschoolers. The volunteers in both Group 1 and Group 2 continued to take their daily pills. All the volunteers developed symptoms of a cold, and there was no significant difference in the length of time the cold symptoms lasted. Make a claim about the Vitamin C.
The Vitamin C was ineffective in reducing cold symptoms.
Be the first group to stand up and shout "Hooray!"!
Hooray! :)