Fundamental Biomedical Techniques - Week 3 Independent and Dependent Variables video

Introduction to Variables in Experiments

  • Terms:
    • Independent Variable: The variable changed by the scientists to test the experiment's hypothesis. This variable differentiates the control group from the experimental group.
    • Dependent Variable: The outcome measured in the experiment, also referred to as data.

Experiment 1: Dimpling Cars to Increase Gas Mileage

  • Hypothesis: Adding dimples to a car's shape could increase its gas mileage, similar to how dimples on a golf ball improve its aerodynamics.

  • Independent Variable:

    • Whether the car had dimples or not (Option C).

  • Rationale: This variable represents the difference between the experimental group (car with dimples) and the control group (normal car).

  • Dependent Variable:

    • The gas mileage of the car (Option B).

  • Rationale: The gas mileage measured depends on the presence of dimples on the car.

Experiment 2: Elephants and Their Fear of Mice

  • Hypothesis: Elephants are afraid of mice.

  • Experimental Setup:

    • A mouse was placed under a cup of elephant dung.
    • When an elephant walked by, the dung was tipped, freeing the mouse.
    • Control setup: Used dung without a mouse.

  • Independent Variable:

    • Whether or not there was a mouse under the dung (Option A).

  • Rationale: This feature differentiates the experimental groups where one has a mouse and the other does not.

  • Dependent Variable:

    • The elephant's reaction during the experiment (Option B).

  • Rationale: The reaction was measured each time the experiment was executed to assess the effect of the mouse's presence.

Experiment 3: Rock from Lawn Mower vs. Bullet from Gun

  • Hypothesis: A rock thrown from a lawn mower can have the same force as a bullet shot from a gun.

  • Experimental Setup:

    • Myths about the energy of thrown rocks were tested by the MythBusters.

  • Independent Variable:

    • The object being tested (Option B).

  • Rationale: This variable indicates the difference between the groups being tested: rock vs. bullet.

  • Dependent Variable:

    • The angle the rig arm went up (Option A).

  • Rationale: The angle depends on which object (rock or bullet) impacts it during the experiment.

Experiment 4: Running in the Rain

  • Hypothesis: Running from shelter in the rain will keep a person drier compared to walking.

  • Experimental Setup:

    • Adam and Jamie walked and ran through rain, measuring the amount of rain collected on their clothing.

  • Independent Variable:

    • The speed of movement through the rain (Option B).

  • Rationale: This variable differentiates the groups based on their movement speed while testing the hypothesis.

  • Dependent Variable:

    • The mass of rain on their clothes (Option A).

  • Rationale: The amount of rain collected depended on whether they were walking or running through the rain.

Conclusion

  • The MythBusters demonstrate the importance of independent and dependent variables in scientific experimentation and logical thinking.
  • Encouragement for audience to engage by leaving questions and subscribing for future content.