BL1002: Biochemical and Cellular Framework

BL1002: Biochemical and Cellular Framework.
In this unit, you are asked to experiment at home which should help you understand some of the critical components of the scientific process. For instance, why do scientists need to conduct multiple measurements or track the uncertainty of their measurements?
Read through the entire post as students have found this additional information supportive of their understanding.

Directions for your engagement are located at the end of the content.
One reason for repeated measures is that measurements can be sloppy, and measurement devices are not always entirely accurate. Another reason is that in addition to measuring a given phenomenon, scientists also want to know how well they have calculated that phenomenon. Repeating a measurement allows us to; measure; the variability or uncertainty.
And yet another reason which applies to your osmosis lab, you may need to be able to figure out when you have detected a significant difference between various experimental conditions.
Other scientific protocols help scientists attain accurate findings in their experimental work. Control groups are an incredibly important facet of scientific research that helps reduce bias and also clarifies the result of experimentation. This action is a critical component of science so let;s spend a little time discussing control groups.

BL1002: Biochemical and Cellular Framework
A typical study might examine the role of a given variable (the independent variable) affecting another variable (the dependent variable.) For instance, one might study the effect that the presence or absence of a fertilizer (independent variable) has on plant growth rates (dependent variable.)

Scientists try to isolate how different variables impact a phenomenon. To distinguish one variable from another, scientists will systematically examine the phenomenon under other conditions. The control condition serves as a baseline. Control groups allow you to compare how exposure to a given phenomenon affects a sample or subject. To do this, samples or subjects, which are otherwise very similar, are separated into two or more groups. One group or sample will be exposed to the phenomenon of interest while the other will not. The effect of exposure to the phenomenon can then be gauged by comparing the two groups.

The osmosis lab also asks you to track the uncertainty in your measurements and ultimately explain the utility of having an uncertainty estimate for these numbers. It turns out that scientists have to spend a lot of time tracking and understanding these uncertainties in their measurements and conclusions.
In your osmosis lab, you had several different solutions and needed to compare what happened to the egg in each solution. If the observed difference between the various experimental conditions is larger than your measurement and the uncertainty, then you can be pretty sure there is a difference in the way these solutions affected the egg. However, if the differences that you observe in your experimental conditions are about the same as your estimated measurement and the uncertainty, then you cannot say that there is any significant effect of the different solutions.
The scientific process is more than just the scientific method, however. The scientific process also
includes the fact that scientists need to communicate their results to other scientists.

Typically, if scientists’ work is found to be engaging other scientists will check it by repeating the same experiments.
Publishing their exact experimental procedure is important so that other scientists can see exactly what was done and repeat it if they desire. Beyond that, including estimates of the uncertainty in their measurements allows scientists to compare measurements on the same phenomenon but conducted by other scientists. If measurements by two different groups on the same phenomenon are no more different from one another than their estimate of uncertainty, then things are good.

However, if one group measures a value that is farther away from the value found by the other group than their uncertainty estimates, then this means that either or both groups made an error in their measurement or an error in their measurement uncertainty.
Your osmosis lab also allows you to investigate a fundamental process by which molecules move across biological membranes: diffusion. All molecules diffuse (move from areas of higher concentration to areas of lower concentration.) If the molecule undergoing diffusion is water, we call it osmosis, but the fundamental physical process is identical.

BL1002: Biochemical and Cellular Framework
To get a sense of the complexity, permeability, and flexibility of plasma membranes, consider this link and image:
https://www.ncbi.nlm.nih.gov/books/NBK9898/
Please do respond after you have reviewed some of the material. Does this make sense? Do you feel comfortable with the importance of estimating uncertainty (or variability) in a scientific measurement?
In your osmosis lab this week, you place your eggs in three different solutions. Is it clear how important it is that you do not simply run an experiment using a single solution?
What exactly is a control group, and why are they important? Why do scientists bother with reporting how uncertain they are about the conclusions that they reach? How do people think the general public understands it when scientists speak not only about their findings but also their uncertainties?

Is this another way that science differs from other approaches to understanding the world? Additional thoughts or questions on the materials
covered in this module?

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