Acids are corrosive to metals whereas bases are slippery.
Acids and bases are easily understood through hands-on activities. Acids are below 7 on the pH scale and can split off hydrogen ions while bases are above 7 on the pH scale and can gain hydrogen ions. Acids are substances such as lemon juice and vinegar, and bases include baking soda and ammonia. Different types of acid and base activities for high school students will help them grasp these chemistry concepts.
Litmus Paper
Litmus paper tests the pH of a substance, which determines whether it is an acid or a base. Making litmus paper will help students understand the testing process. Tear pieces of red cabbage and boil them in water for 15 minutes. Strain the liquid into a glass container. Saturate strips of paper towels into the liquid and allow it the dry completely. The red cabbage juice has a pigment molecule called flavin, which will turn red for acidic substances and green-yellow for basic substances. Once the strips are dry, the homemade litmus paper will be ready.
Testing
A simple experiment of testing the pH of different household items is another acid and base activity for high school students. Students should make predictions first about whether substances such as potatoes, liquid soap, apples, vinegar, milk and water are acids, bases or neutral. Litmus paper should be used if students do not make homemade indicator paper from red cabbage juice. Create a chart with the predictions and the results.
Neutralization H2O + NaCl. The solution is neutralizing, but only one hydrogen ion has been decreased. Test the solution with litmus paper and proceed to add more sodium hydroxide slowly until it is neutral.
Computer Games
High school students should also use the computer for more acid and base activities. Websites such as Houghton Mifflin Harcourt Publishing and UC Berkeley offer free online games about acids and bases. The Houghton Mifflin Harcourt Publishing site has a game in which students guess what a substance is after testing its pH while UC Berkeley's GEMS Alien Juice Bar Game offers three challenges. One is to set up a juice bar with acids and bases, the second is identifying acids, bases and neutrals, and the third is mixing the substances.
Tags: acid base, acids bases, school students, base activities, cabbage juice
