Exploring Controlled Experiments in Biology

The video tutorial explains what a controlled experiment is and why it's important for testing scientific hypotheses. It uses an example of testing a fertilizer's effect on plant growth. The process involves setting up two identical plants, with one receiving fertilizer and the other not, to observe differences in growth. The tutorial covers the importance of controlling variables, measuring results, and analyzing data to support or refute a hypothesis. It also introduces the concepts of independent and dependent variables.

What is the purpose of a controlled experiment?

• To observe natural conditions

• To control all variables except one

• To test multiple variables at once

• To change all variables simultaneously

What is a scientific hypothesis?

• An untestable theory

• A proven fact

• An idea that explains a situation

• A random guess

What is the first step in designing a controlled experiment to test fertilizer?

• Get two plants of the same species

• Place plants in different locations

• Choose different species of plants

• Use different types of soil

Why is it important to keep all conditions the same for both plants in the experiment?

• To save time and resources

• To test multiple variables

• To make the experiment more complex

• To ensure the fertilizer is the only variable affecting growth

What is the only difference between plant A and plant B in the experiment?

• Plant A gets more sunlight

• Plant B gets more water

• Plant A receives fertilizer

• Plant B is in a larger pot

How would you determine if your hypothesis is correct?

• By moving the plants to different locations

• By changing the soil type

• By measuring the plants regularly

• By observing the plants once

What should you do with the measurements taken during the experiment?

• Only measure plant A

• Change the experiment setup

• Record and compare them

• Ignore them

What does it mean if plant A grows bigger than plant B?

• The fertilizer does not work

• The hypothesis is supported

• Both plants are identical

• Plant B needs more water

What is the independent variable in this experiment?

• Plant growth

• Amount of sunlight

• Type of soil

• Fertilizer

What is the dependent variable in this experiment?

• Type of plant

• Plant growth

• Amount of water

• Temperature