Chemistry 101: The Scientific Method

The Scientific Method

Chemistry 101: 8th Grade Science

          While studying chemistry, a technique designed to investigate scientific questions is called the scientific method. This method is a way of asking a question and then answering it and making conclusions based on specific steps. Here are the steps of the scientific method:

• Step one: Ask a question. Every investigation begins with an intellectual question that ponders something about the world. This question needs to be something that can be tested and that can have an experiment conducted for it. Think about what you specifically hope to discover in the end, and how you will go about testing this.

• Step two: Make observations. After thinking about the question you would like to answer, make observations about the matter at hand. Before doing any testing, you must always make your own observations beforehand so that you can formulate an educated guess as to what the outcome will be.

• Step three: Formulate a hypothesis. What do you believe, according to the observations made, will be the outcome of the experiment you wish to perform? Make an educated guess based on what you already know. The usual format of a hypothesis is as follows: If ____, then ___.

• Step four: Test your hypothesis. Design an experiment that specifically answers the question you have asked. Make it simple and to the point to ensure accurate findings. Make a step by step procedure that conducts a fair test that is not in any way biased.

• Step five: Analyze the data. Record your findings from the experiments tested and draw conclusions about your hypothesis. Accept or reject the hypothesis you came up with and be able to explain why, through means of testing, this came to be.

          Using the scientific method is an extremely useful way to ask a question and then find the answers. These specific steps will help you as you begin to conduct experiment in your chemistry class!

Chemistry 101: Significant Figures

Significant Figures

Chemistry 101: 8th Grade Science

          Making measurements is a very important aspect of studying chemistry. Whether this be measuring the volume using a graduated cylinder, or weighing mass on a balance, or even simply measuring the length of something, making precise measurements is a very imperative piece of studying this topic. However, every experimental measurement, no matter how precise, has a degree of uncertainty to it because there I always a limit to the number of digits that can be determined. In order to keep a measurement accurate, the value recorded should use all the digits known with certainty. These specific numbers of digits are also referred to as SIGNIFICANT FIGURES. Significant figures are the numbers of meaningful digits use to express a value.

Determining the number of significant figures can normally be simple, however this can get more challenging when there are zeroes involved. Here are some rules to help you determine the number of significant figures are needed when zeroes are present: 

• Rule 1: Zeroes sandwiched between two non-zero numbers are always significant (Ex. 4.708 has 4 significant figures)
• Rule 2: Zeroes at the beginning of any number are not significant and simply act to locate the position of a decimal (Ex. 0.036 has 2 significant figures)
• Rule 3: Zeroes at the end of a number after a decimal point are significant or they would not be recorded (Ex. 183.400 has 6 significant figures)
• Rule 4: Zeroes at the end of a number before a decimal point may or may not be significant. It depends if they are part of the measurement or if they act to indicate an implied decimal place

Always remember to be mindful of significant figures when making measurements in the laboratory. They keep the data as accurate and precise as possible and help to avoid any calculation error that may result from inaccurate data!

Chemistry 101: The Periodic Table

The Periodic Table

Chemistry 101: 8th Grade Science

 

The Periodic Table of Elements is an extremely useful tool when studying chemistry. The periodic table is an organization of all elements based on different chemical properties in the form of a table. The horizontal rows, also known as periods, order the elements by increasing atomic number from left to right. The vertical columns are also referred to as groups.

 

Each element has its own box on the periodic table which reveals some very important information. First, each element is written in shorthand notation. This is usually a one or two letter symbol with that contains a capitalized first letter and a lower case second letter. Every element differs from all others according to how many protons it contains. This value is also referred to as the atomic number. (The number of protons is equal to the number of electrons, thus if we are given either the number of protons or electrons of any given element, we can find the atomic number and identify it) The atomic number of an element usually appears as a small above the element symbol. As stated above, the elements are organized into periods of increasing atomic number from left to right.  

 

There is also a small number printed below the element symbol, which signifies the atomic mass of that specific element. The atomic mass is the weighted average mass of an element’s atoms. Lastly, the periodic table can also show what sub group a certain element is in. Usually these subgroups are colored differently. The main subgroups include: Main group elements, transition metal elements, and inner transition metal elements.