Defintions
The ________ variables are all the things that you keep the same in every trial.
What is control variables?
Identify the independent variable:
Cam Cameron is testing the effect of temperature on the time it takes for ice to melt.
What is temperature?
Identify the Dependent Variable:
Katie wanted to find out what shampoo made her hair the shiniest. Everyday she washed her hair with different shampoos and then rated how shiny her hair was, on a scale from 1-10.
Identify 1 Control Variable:
Lexi wants to find out which frozen solid melts the fastest: soda, ice, or orange juice. She pours each of the three liquids into the empty cubes of an ice tray, and then places the ice tray in the freezer over night. The next day, she pulls the ice tray out and sets each cube on its own plate. She then waits and watches for them to melt. When the last part of the frozen liquid melts, she records the time.
What is "If...Then.." statement?
A ___________ statement that predicts the outcome of an experiment.
What is hypothesis?
Identify the Independent Variable:
Carolina is testing how the type of music affects test scores.
What is the type of music?
Identify the dependent variable:
Denmark wanted to test how the mass of a paper airplane affected the distance.
What is the distance?
Identify 2 Control Variables:
Jack wants to find out which laundry detergent cleans the best (Gain, Tide, or Purex). So, he takes a cotton sheet and cuts it up into equal squares. He stains four squares with chocolate, and four with grape juice. He washes one of each of the squares in each of the 3 detergents. One from each set of squares is washed in water alone. For each wash load, he used: the same amount of water, the same amount of detergent, and the same temperature of water.
Must be something that is kept the same throughout.
A good hypothesis should be ________.
What is testable?
The ______ variable is the one that you change on purpose in an experiment.
What is independent variable?
Identify the Independent Variable:
Sid wants to find out what fertilizer works best for growing carnations.
What is fertilizer?
Laura tested the effect of temperature on the time it takes for ice to melt.
What is the time it takes for the ice to melt?
Identify 3 Control Variables:
A scientist knows that the percent of fish eggs that hatch is affected by the temperature of the water in an aquarium. She is attempting to identify which water temperature will cause the highest percentage of fish eggs to hatch. The scientist sets up 5 aquariums at the following temperatures: 10°C, 20°C, 30°C, 40°C, and 50°C. She adds 50 fish eggs to each aquarium and records the number of eggs that hatch in each aquarium.
Must be something that never changes in the experiment.
Write a hypothesis for this question:
Does the type of liquid affect how fast an ice cube melts?
Must be in "If...Then..." format.
The ______ variable is the one that you measure or observe during an experiment.
What is dependent variable?
Identify the Independent Variable
Anna wanted to see what battery lasted the longest. She put each battery into a clock and recorded the time that the clock stopped.
What is the type of battery?
Identify the Dependent Variable:
Maverick wants to find out whether or not Miracle Grow really makes plants grow faster.
What is height of the plant?
If you are testing if sunlight plays a role in the growth of the plants, what would some of your controls be?
Must be something that remains the same.
Write a hypothesis for this question:
Does fertilize affect plant growth?
Must be wrote in "if...then..." format.
Which variable is purposely changed by the experimenter?
What is independent variable?
Identify the Independent Variable
Carol tests if watering plants with sugar water makes them grow taller than with regular water.
What is the type of water?
Identify the Dependent Variable:
CJ wanted to see if listening to music would make the basketball players make more baskets. On day one, he didn't play any music and counted how many baskets they could make in 10 minutes. On day 2 he played pop music and counted the baskets, and on day 3, he played classical music and counted the baskets.
Why is it important to keep control variables the same in an experiment?
So that you know any changes in the results are caused by the independent variable.
Why is having a hypothesis important?
It helps the researcher guide their investigation.