Daphnia heart rate temperature lab report

Laboratory 3 The Scientific Method

Objectives

· Understand the steps involved in the scientific method

· Define and identify: independent, dependent and control variables

· Calculate the heartbeat of Daphnia under various experimental conditions

· Analyze the data obtained

· Make conclusions regarding the various variables tested and Daphnia’s heart rate

Background Information

All fields of science have one unifying principle that is a common tie among these diverse scientific disciplines. That unifying theme is the scientific method .

The scientific method is simply an organized, methodical, and structured way of observing and/or investigating a situation in an effort to find information about what is being observed. There are six steps to the scientific method.

1. Identification of the situation to be investigated.

This is vital because no progress can be made towards understanding the situation unless one knows exactly what is being investigated. Let’s consider an example. Suppose that you notice (observe) a list of essential nutrients on the label of a box of plant fertilizer. You wonder how plant growth might be affected if plants are deprived of just one of those essential nutrients. You decide to investigate the effect of the lack of potassium on pepper plants.

2. Obtain information about the situation being investigated.

One of the biggest advantages in problem solving is knowing the background information about what is being investigated. This is why researchers do searches of the scientific literature when writing a paper or conducting research. Accordingly, you would go to the library and read as much as you can about plant nutrition and how potassium affects plant growth.

3. Formulation of a hypothesis.

A hypothesis is a possible explanation of the problem or situation based only on what it is known about it so far. The hypothesis must be testable: an experiment must be designed to test its validity. Another important characteristic of a hypothesis is that it must be falsifiable. This means that the hypothesis must make predictions that could be proven false by experimental results. Your first hypothesis might be, “Plants grown in a medium lacking potassium will show some specific signs of malnutrition.

4. Predict the results.

Assuming your hypothesis is correct, you ought to be able to predict the outcome of a situation where your hypothesis was actually applied to the problem. You might now try to imagine how a pepper plant would look when grown in a potassium-free medium. Perhaps there would be obvious changes in the leaves and/or the stem height.

5. Design and conduct an experiment to test the hypothesis.

An experiment is an investigation conducted under very specific conditions in which all variables are controlled except the one being studied. A variable is an event or condition subject to change. In the potassium study, the lack of potassium is the variable being investigated.