Monthly Archives: April 2015

Statistics Bar Graph — The term “average” is not used in statistics. Statisticians will choose what they mean by the term “average” depending on the way they are going to use their data. Instead, they use the terms mean, median and mode to express an “average” for numeric data. MEAN, MEDIAN, MODE, AND RANGE DEFINITIONS First, […]

How to Calculate Mean, Median and Mode

This entry was posted on April 30, 2015 by Todd Helmenstine (updated on June 4, 2018)

SI Units Word Search — This SI units word search puzzle contains vocabulary words dealing with base and derived SI units used in science. These terms can be found horizontally, vertically, and diagonally. Click the image for full-size or download the PDF and give it a try. If you would like some help finding some of the terms, take a peek […]

SI Units Word Search Puzzle

This entry was posted on April 29, 2015 by Todd Helmenstine (updated on May 15, 2015)

Mixtures Worksheet — Mixtures can be a confusing topic for new chemistry students. On the surface, mixtures do not seem all that complicated. A mixture is a collection of different materials. Take more than one thing, combine them and you have a mixture. Mixtures can be further classified as either homogeneous or heterogeneous […]

Homogeneous or Heterogeneous – Mixtures Practice Worksheet

This entry was posted on April 27, 2015 by Todd Helmenstine (updated on August 25, 2020)

Periodic Table of Fireworks — Fireworks are a colorful display on summer nights. Have you ever wondered about the chemistry of those bright colored explosions? The colors produced depend on the elements added to the firework before they are launched. This periodic table of fireworks highlights the common elements used to produce colors and effects. Element 3: […]

Periodic Table of Fireworks

This entry was posted on April 26, 2015 by Todd Helmenstine (updated on July 6, 2019)

Dilution — In most laboratory settings, a stock solution is created when a compound is used over and over. This stock solution will have a high concentration. If lower concentrations are needed, a dilution is performed. A dilution is a process where the concentration of a solution is lowered by adding solvent […]

Dilution Example Problems

This entry was posted on April 20, 2015 by Todd Helmenstine (updated on April 21, 2015)

Azote Periodic Table Tile — You may be familiar with the element symbols found on the periodic table. These symbols are standardized by the International Union of Pure and Applied Chemistry (IUPAC) for international use. When a scientist believes he has discovered a new element, he usually announces his discovery along with a new name and […]

Element Symbols No One Uses

This entry was posted on April 15, 2015 by Todd Helmenstine (updated on April 16, 2015)