Lab 1: Scientific Method

How is a scientific theory different from a conclusion?

A conclusion is based on observations and experiments completed within a limited time frame. A scientific theory is based on observations and experiments completed over an extended time frame.

What do you call a sample that goes through all the steps of an experiment, but is not exposed to the experimental variable?

Control.

In science, a conclusion is based on the data. Explain.

Data are objective, factual information gained by making observations and doing experiments.

What do you call the information scientists collect when doing experiments and making observations?

Data.

What is your experimental variable?

Degree of exercise.

What are some of the possible variables that should be controlled or they may affect the reliability of your results?

Physical attributes of the subject; how fast the subject walks vs. how fast the subject runs.

What is the purpose of a control?

The purpose is to guard against coming to a false conclusion.

What is the function of a beating heart?

To keep the blood moving in the arteries.

Think of an exercise a subject could do in the laboratory at a slow speed and a fast speed.

walking vs. running for 10 sec. Slow exercise/time: Walking in place for 10 sec. Fast exercise/time: Running in place for 10 sec. Hypothesis: The heart rate will increase more after running than after walking for 10 sec.

The data show that vaccines prevent people from disease.

Conclusion.

What step in the scientific method follows experiments and observations?

Conclusion.

What is your evidence that a beating heart is critical to good health?

If the heart stops beating, the person dies.

Explain what a scientist means by the term theory.

A theory in science is about a conclusion based on many individual conclusions in the same field.

How do scientists carry out the first step in the scientific method?

By making observations.

As scientists do, before you begin your experiment, summarize your experimental design.

Each member of the class (subject) will exercise slowly (e.g. walking in place for 10 sec) and rapidly (e.g. running in place for 10 sec). The pulse rate before and after slow and fast exercise will be taken utilizing the radial artery. Control: The control subject will neither walk nor run. The pulse rate will be taken before starting and after finishing the experiment.

Why is a hypothesis called a tentative explanation?

Further observations or experiments will produce the data that support or do not support the hypothesis.

Why is a hypothesis sometimes called an "educated guess?"

Hypotheses represent an "idea" that has not been tested yet.

What is a tentative explanation of observed phenomena?

Hypothesis.

What will be a dependent variable in your experiment?

Increase in pulse (heart) rate due to exercise.

Why is it helpful for a scientist to begin by making observations?

Making observations will permit formulating a hypothesis.

Why don't scientists say they have proven their hypothesis true?

More information, perhaps gathered by improved instrumentation, can later falsify the hypothesis.

The heart rate is the same as what other cardiovascular system rate?

Pulse rate.

All living things are made of cells.

Scientific theory.

Why must a scientist keep complete records of an experiment?

So that other scientists can see how the experiment was done and perhaps do the same experiment themselves.

What is the normal heart rate when at rest?

The average adult human heart beats at about 72 beats per minute.

Which is more comprehensive, a conclusion or a theory?

Theory.