Unit 1: Review (Science)

Unit 1: Science

Review

The Scientific Method

• At the core of biology and other sciences lies a problem-solving approach called the scientific method. The scientific method has five basic steps, plus one feedback step:

• Make an observation

• Ask a question

• Form a hypothesis, or testable explanation

• Make a prediction based on the hypothesis

• Test the prediction

• Iterate: use the results to make new hypotheses or predictions

Multiple Select

What are the correct steps to the scientific method?

• Observation

• Running for energy

• Hypothesis

• Drinking Water

Controlled Experiments

What are the key ingredients of a controlled experiment? To illustrate, let's consider a simple (even silly) example.

Suppose I decide to grow bean sprouts in my kitchen, near the window. I put bean seeds in a pot with soil, set them on the windowsill, and wait for them to sprout. However, after several weeks, I have no sprouts. Why not? Well...it turns out I forgot to water the seeds. So, I hypothesize that they didn't sprout due to lack of water.

To test my hypothesis, I do a controlled experiment. In this experiment, I set up two identical pots. Both contain ten bean seeds planted in the same type of soil, and both are placed in the same window. In fact, there is only one thing that I do differently to the two pots:

One pot of seeds gets watered every afternoon. The other pot of seeds doesn't get any water at all.

After a week, nine out of ten seeds in the watered pot have sprouted, while none of the seeds in the dry pot have sprouted. It looks like the "seeds need water" hypothesis is probably correct!

Let's see how this simple example illustrates the parts of a controlled experiment.

Multiple Choice

One type of scientific investigation that tests a hypothesis under controlled conditions and includes a

• Question

• Control Group

Variables:

Something that changes in a scientific investigation.

(Some changes you make on purpose. While some changes happen as a result of you testing something.) 

vary = change

Test Variable (Independent Variable)

The change you make on purpose to TEST during an experiment or investigation.

It can and HAS to be controlled.

You can test ONLY 1 of these at a time!

The new thing being tested DOES NOT go on the control group!

Outcome Variable (Dependent Variable)

This is a change that happens as a result of you testing something.

You can have as many of these as you want because you can measure anything you want!

It is the factor you OBSERVE and/or MEASURE in a scientific investigation.

It CANNOT be controlled!