Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
A Fair Test is a scientific investigation where only one variable is changed, while all other conditions are kept the same to ensure the results are valid.
The Independent Variable is the factor that you deliberately change (e.g., the temperature of water ).
The Dependent Variable is the factor that you measure or observe to get your results (e.g., the time it takes for sugar to dissolve).
Control Variables are all the other factors that must be kept constant (e.g., using the same volume of water and the same mass of sugar ).
A Prediction is a smart guess about what will happen, often written as: 'If I change [Independent Variable], then [Dependent Variable] will [increase/decrease/stay the same].'
To make results more reliable, scientists repeat the experiment at least three times and calculate an average (mean).
📐Formulae
💡Examples
Problem 1:
An explorer wants to find out which type of soil allows water to pass through the fastest. She tests sandy soil, clay soil, and loamy soil. She pours of into each. Identify the variables.
Solution:
Independent Variable: Type of soil; Dependent Variable: Time taken for water to pass through (); Control Variables: Volume of water (), the amount of soil used, and the size of the funnel.
Explanation:
To make it a fair test, only the soil type should change. If she used different amounts of water, she wouldn't know if the soil type or the water volume caused the difference in time.
Problem 2:
A student measures the growth of a plant over 4 weeks. In Week 1 it was , and in Week 4 it was . Calculate the total growth.
Solution:
Explanation:
The total change in the dependent variable (height) is found by subtracting the initial value from the final value.