The Scientific Method

Abstract

The scientific method is a systematic approach scientists use to direct their research and answer questions. In the following experiment, the student is able to practice the use of the scientific method by first forming a hypothesis, then performing experiments to test the hypothesis, and then deciding if those experiments supported the hypothesis. When the experiments did not support the hypothesis, another one was made. This was done by systematically observing the properties of six unknown substances. Observations were made and data was accumulated. The identity of the unknown substances was discovered by applying the scientific method.

Purpose

The objectives of this lab were to learn the basic steps of the scientific method, to formulate a hypothesis, and to systematically observe properties of unknown substances. The focus of the lab was to practice forming a hypothesis, and then testing that hypothesis.

Materials and Methods

The lab began with visual examination of six unknown substances. Upon visual examination, the color of each item was decided, and a hypothesis was made about what the unknown substances were. This hypothesis was tested with experiments. The first experiment was to measure the volume of each substance using the markings on the vials. Volume was measured in cm 3. Next, the mass of each substance was determined using a spring scale. Mass was measured in grams.

The next series of experiments were qualitative observations. The texture was determined by rubbing the substance between the fingers. Shape was determined using a magnifying glass. Smell was determined using the method where the fumes were directed toward the nose using hand motions, not by smelling the substances directly. The final test was done to determine solubility of each item. A pea size amount of each item was placed in a test tube. Five ml of distilled water was added to the test tube and the test tube was shaken. The solubility was determined by observing whether or not the item completely dissolved in the water, or if any particles of sediment settled to the bottom of the test tube.

In order to complete the lab, the data was analyzed, and the hypotheses were updated. This allowed the student to experience all the steps of the scientific method. The final step is to share the results.

Results

The results of this experiment showed how some hypotheses were proven with further experiments, and some were disproven. Results also showed how a better hypothesis could be made after performing the experiments. Out of six substances, only three of my original hypotheses were correct. By performing further experiments, the identity of those three substances was confirmed. The substances whose identity were correctly hypothesized, and were confirmed through further experiments were the first three vials. The results confirmed that vial number one was ground nutmeg, vial two was potting soil, and vial three was brown sugar.

The remaining three hypotheses were changed following the experiments. Out of the remaining three vials, the identity of two of the substances was discovered, and the third remained a hypothesis. Vial number five was discovered to be baby powder through the qualitative measurements of smell and texture. Vial number six was discovered to be cornstarch by feeling its texture, and also by discovering that it was not water-soluble. Vial number four was not one hundred percent identifiable through the experiments performed on it. Although, following the experiments, it was determined that the original hypothesis, that it was flour, was incorrect. The new hypothesis made for vial number four was that it is tooth powder.

The following data charts show the findings of the experiments.

Data Table 1: Scientific Method Data

Unknown Sample Number #1 #2 #3 #4 #5 #6

Hypothesis Ground nutmeg Potting soil Brown sugar Flour Powdered sugar Baking powder

Color Brown Dark brown Light brown White White White

Texture: Gritty Course Gritty and sticky Smooth Silky Smooth with slight stickiness

Shape: Sharp edges Irregular shaped edges Crystalline Smooth Smooth Powdery

Smell: Nutmeg Dirt Sugar Light