Variable Lab
In an experiment testing how fertilizer affects tomato plant height, this is the factor the scientist intentionally changes or tests.
What is the Independent Variable?
Hypothesis: "If a glowstick is placed in boiling water, then it will glow brighter than at room temperature." State an experimental procedure to test this.
What is: Place identical glowsticks into beakers with different water temperatures (e.g., boiling vs. room temp) and measure their brightness/light intensity?
A dog owner wants to know if a grain-free diet cures her dog's itching. Over two weeks, she switches the dog's food to grain-free, buys a new shampoo, and washes the dog's bed daily. The itching stops. Why can't she conclude that the food was the cure?
What is: She changed multiple independent variables at once (food, shampoo, bedding), so she cannot isolate which change cured the itching?
Put these standard scientific inquiry steps in logical order: Analyze Data, Form a Hypothesis, Draw Conclusions, Ask a Question, Conduct an Experiment.
What is:
When graphing experimental data on a standard line or bar graph, this variable always belongs on the x-axis (horizontal).
What is the Independent Variable?
A student tests three shoe brands to see which lets runners sprint fastest. The sprint time recorded on the stopwatch is this type of variable.
What is the Dependent Variable?
Experiment: A student drops basketballs from heights of 1 meter, 2 meters, and 3 meters onto concrete and measures the height of each bounce. State the hypothesis being tested using an "If... then..." format.
What is: "If a basketball is dropped from a higher drop point, then it will bounce higher"?
Two students want to find out which brand of battery lasts longest in a flashlight. Student 1 leaves Flashlight A turned on continuously. Student 2 turns Flashlight B on for 10 minutes every hour. Explain why their results cannot be compared.
What is: Usage time/duty cycle was not held constant, introducing an uncontrolled variable?
True or False: The Conservation of Mass is a theory.
What is false?
When graphing experimental data, this variable always belongs on the y-axis (vertical).
What is the Dependent Variable?
To ensure an experiment testing paper towel absorbency is fair, the sheet size, water temperature, and pour speed must stay exactly the same. These factors are called this.
What are Constants (or Controlled Variables)?
Hypothesis: "If bread is kept in a moist container, then it will grow mold faster than bread in a dry container." Identify the independent variable and the dependent variable for this planned experiment.
What is:
A baker wants to see if adding extra sugar makes bread dough rise higher. She prepares four bowls:
What is Bowl 1 (the Control Group)?
Newton's Law of Universal Gravitation calculates the exact pull between two objects (F = G \frac{m_1 m_2}{r^2}), while the Theory of General Relativity explains that gravity is caused by mass curving spacetime. State which one explains HOW/WHY and which one describes WHAT happens.
What is The Theory explains HOW/WHY; the Law describes WHAT happens?
A scientist records temperature changes over 24 continuous hours. State whether a Bar Graph or a Line Graph is best suited for showing this continuous change over time.
What is a Line Graph?
In a medical trial testing a new allergy pill, Group A receives the real medication, while Group B receives a sugar pill with no active ingredients. Group B serves as this.
What is the Control Group?
Experiment: A gamer tests whether wearing blue-light glasses improves reaction time in a video game over 10 trials, comparing scores with glasses on vs. glasses off. Write a complete, testable hypothesis for this setup.
What is: "If a player wears blue-light glasses, then their reaction time in the game will decrease/improve compared to playing without glasses"?
An experiment measures the strength of three bridge designs by stacking weights on each until it collapses. Design A breaks at 12 kg, Design B at 18 kg, and Design C at 15 kg. Identify the measured outcome that determines which bridge is strongest.
What is the maximum weight held before collapse (the Dependent Variable)?
Mr. Spooky wants to test the following hypothesis: If drinking milk affects my mood, then drinking milk will make me feel braver. What experimental design could he form and test?
The basis of the hypothesis is flawed. Feelings and moods are not quantifiable metrics and therefore no valid experiment could test these variables.
Look at this data trend:
What is a direct/positive relationship (as study time increases, test score increases)?
A scientist wants to test if a new engine oil improves car gas mileage. Explain why the scientist cannot test both a new oil and a new gasoline brand in the experimental group at the same time.
What is: Testing more than one independent variable at a time makes it impossible to know which variable caused the change in the results?
Experiment: Three identical metal spoons are placed into boiling water: one with a plastic handle wrap, one with a wooden handle wrap, and one bare metal spoon. The scientist measures how long it takes wax on each handle to melt. Identify what question this experiment is designed to answer.
What is: "Which handle material is the best heat insulator (or prevents thermal conduction the best)?"
A farmer treats three fields with different water salinity levels to see which produces the most corn. Field A has 0% salt, Field B has 1% salt, and Field C has 3% salt. If the farmer wants to label the cause and the effect, what is the cause and what is the effect?
What is:
Explain why scientific knowledge is considered open to change rather than 100% permanent absolute truth.
What is: New evidence, better technology, or new observations can lead scientists to revise or improve existing theories and explanations?
A graph title reads: "The Effect of Tire Tread Depth (mm) on Braking Distance (meters)." Identify the independent and dependent variables purely from reading this title.
What is: