Question

Part C: Review Questions

How did holding your breath affect your heart rate?
Does the data support or refute the hypothesis?
Other than holding your breath, what can affect your heart rate? List at least three variables that can affect heart rate.
Choose one of the variables from your list, and design an experiment to test the impact on heart rate.
Formulate a hypothesis about how the variable will affect heart rate.
Test your hypothesis, and record the data in a data table similar to the one above.
Support or refute the hypothesis based on the results.
Why is it important to test only one variable during an experiment?

Answer 1

PART A:

Independent variable: number of cigarettes smoked

Dependent variable: risk for lung cancer

Independent variable: number of sharks swimming in a coastal region

Dependent variable: number of shark attacks on humans

Independent variable: amount of milk a person drinks

Dependent variable: the strength of his or her bones

PART B:

Hypothesis: If I hold my breath for 30 seconds, then my heart rate will

(choose 1) increase/decrease.

Independent variable: holding my breath

Dependent variable: heart rate

PART C:

The heart rate decreases because oxygen exchange in the lungs decreases.

This depends on what you chose for heart rate in the hypothesis. If you said the heart rate decreases after holding your breath, and the results showed the heart rate decreased, then the hypothesis is supported. If you said the heart rate decreases after holding your breath, and the results showed the heart rate increased, then you refuted the hypothesis.

Heart rate can change due to an increase or decrease in activity, moving positions such as sitting and standing, and emotions.

Example: Increase in activity—jumping jacks

Hypothesis: If I do five jumping jacks, then my heart rate will increase.

Test hypothesis. You can use the average resting heart rate from the previous experiment. If you do an experiment with an increase in physical activity like jumping jacks, then your data will reflect an increase in heart rate because the body requires more energy, which requires more oxygen, increasing the overall flow of blood in the body.

Support or refute the hypothesis based on the results. The hypothesis is supported if it aligns with the observed results. The hypothesis is refuted if the results don’t match the statement based on the variables.

Testing more than one variable at a time makes it difficult to interpret the results and support or refute the hypothesis. With one variable, the results can be associated with changes to that variable. To get the most reliable data to support or refute a hypothesis, an experiment should be completed several times to see if the results show the same trends. Refer to page 6 in your textbook.

Step-by-step explanation:

Straight from Penn Foster! Hope this helps!!!!