IMAGE. The test tube is correctly held away from the face. Remember to keep the opening of the test tube pointed away from you and your neighbor.
Video. Result of adding water to acid.
When mixing or heating, NEVER point the mouth of a test tube or Erlenmeyer flask at yourself or another person! ALWAYS direct the mouth away from people!
Sometimes, heat is evolved when substances are mixed. Always have a place to set a vessel that gets too hot to handle. An easily available test tube rack and an area cleared of notebooks, glassware, and other items is important in the laboratory.
In addition, do not set glassware or test tube racks near the edge of the laboratory bench, where they may easily be knocked over.
If the two liquids are water and an acid, always add the acid to the water slowly. Never add the water to the acid. (Acid to water has the first letters of the words in alphabetical order.)
