IB Chemistry: Validity Part 1

The video tutorial covers the concept of validity in IB chemistry experiments, focusing on the roles of independent, dependent, and controlled variables. It uses an archery competition analogy to explain how these variables affect the validity of an experiment. The tutorial emphasizes the importance of changing only one independent variable at a time to draw valid conclusions. It also discusses how to measure dependent variables accurately and the necessity of maintaining controlled variables to ensure experimental validity. The video concludes with a recap of the key points discussed.

What is the primary aim of a science experiment?

• To change as many variables as possible

• To ensure all variables are independent

• To see how changing the independent variable affects the dependent variable

• To measure all possible outcomes

In the archery competition example, what was the independent variable?

• The type of bow used

• The weather conditions

• The distance to the target

• The archer

Why is it important to have only one independent variable in an experiment?

• To ensure the experiment is quick

• To make the experiment more complex

• To attribute changes in the dependent variable to a single cause

• To allow for multiple conclusions

What is a dependent variable in an experiment?

• A factor that is measured

• A factor that is kept constant

• A factor that is ignored

• A factor that is manipulated

In the zinc and hydrochloric acid experiment, what was the dependent variable?

• The volume of hydrogen gas produced

• The amount of zinc used

• The temperature of the reaction

• The concentration of hydrochloric acid

Why is it important to select the correct dependent variable?

• To measure irrelevant factors

• To ensure the experiment is expensive

• To obtain valid results that address the experimental aim

• To make the experiment more difficult

What is a controlled variable?

• A factor that is kept constant in an experiment

• A factor that is ignored in an experiment

• A factor that is changed in an experiment

• A factor that is measured in an experiment

In the archery competition, why must all archers use the same type of bow?

• To ensure the competition is more challenging

• To make the competition faster

• To ensure fair comparison of archery skills

• To allow for different styles of shooting

Why is it important to control environmental conditions in an experiment?

• To make the experiment more exciting

• To ensure that changes in the dependent variable are due to the independent variable

• To allow for unexpected results

• To make the experiment easier to conduct

What is the key takeaway about validity in experiments?

• Validity is only about measuring the dependent variable

• Validity only applies to chemistry experiments

• Validity ensures that the experiment tests the aim and hypothesis accurately

• Validity is not important in experiments