Unit 1 - Scientific Method/Molecules Reading Assignment: Background information

Question

Unit 1 - Scientific Method/Molecules

Reading Assignment: Background information for Unit 1 : Audesirk, Audesirk, & Byers (9th Ed.), Chapters 1-3; Chapter 34, Nutrition
Assignment Type: Individual Project Deliverable Length: 2-3 pages
Points Possible: 125 Due Date: 6/12/2011 11:59:59 PM CT


Background: Scientific inquiry in biology starts by observing the living species around us. Science is a way of knowing. It is not the only way, but it is a good way. Other ways of knowing include mathematics, logic, history, philosophy, and theology.

What separates science from the other methods of seeking truth is that it is testable (i.e. one can devise experiments to test the validity of an idea); it is falsifiable (i.e. an experiment can reveal if an idea is false); and, it involves natural causality (i.e. the method involves and depends upon the natural laws of the universe which cause things to happen in a predictable and repeatable manner.)

Observation: Scientific inquiry begins when something interesting gets your attention.

Question: Following an observation, a question arises in your mind. It may be something like: "I wonder what...? Or "I wonder how …? Or, "I wonder why…?

Assignment details:

In this assignment, we will take a look at science and the scientific method. Then, you will design a (pretend) scientific study to answer a specific question based upon an observation.

First, choose ONE of the following Observations /Questions:

Option A:

Observation: During the winter, you spread salt daily on your driveway to melt the snow. In the springtime, when the lawn begins to grow, you notice that there is no grass growing for about 3 inches from the driveway. Furthermore, the grass seems to be growing more slowly up to about 1 foot from the driveway.

Question: Might grass growth be inhibited by salt?

I

Explanation / Answer

I am going to assume you are going with Option A. Okay, so your question is that you want to know if the growth of the grass is inhibited by salt based upon your observations of the grass near the driveway that was salted in the winter time. So how will we use science to answer this question? In the background, it was stated that science is testable. So what will we do? We will explore this question by designing a test to see if the salt was indeed the culprit for inhibiting/preventing the growth of the grass. This is the sort of experiment I would set up. I would plant an equal mass of grass seeds in each of several separate pots all located in a location where they would receive equivalent amounts of sunlight, and also ensure that the same amount and type of soil is used for each one. Each one should be watered equal amounts at an equal frequency. The only differences among them should be the concentration of salt added to the soil. Why is this, you ask? Because in order for your results to be sound, you need to control for other factors that might influence the grass' growth, like water, sunlight, soil type, and temperature. If they're all in the same place, they will all have basically equal amounts of sun exposure, and will all be at the same temperature, right? The amounts of salt that you add to each of your pots may vary--you might even want to have more than one pot with the same amounts of salt added to produce even stronger results (we call these "replicates" in the scientific community), but you do need at least one "control", or pot to which no salt was added, to ensure that the seeds are actually viable. So then you sit back and watch the grass in each of the pots grow. You ask yourself, how did the growth of the grass with salt added to the soil compare to the growth of the grass without salt? Did the grass with more salt added to it grow more slowly (or not at all) in comparison to the grass with less salt added? If that is the case, then most likely we can conclude that the results of the experiment support your initial idea (in science we call it a "hypothesis") that salt inhibits the growth of grass. Take note that I said "support". In science nothing can ever really be "proved". We can only be reasonably certain when the results of multiple experiments support our hypothesis. Hope this helped, if anything was unclear feel free to ask.

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