Some good chemical experiments for science class include testing the evaporation times of different liquids, analyzing the cleaning potency of different liquids on coins and examining how much gas different liquids produce. All of these experiments allow students to observe different chemical reactions.
By analyzing the evaporation times of different liquids, students can learn about the differences in chemical composition and how they affect chemical reactions. For the experiment, students should select a variety of liquids and place them in identical beakers with measured gradients. The liquids should be of different compositions, such as water, milk, juice, soda and nail polish. Students can then observe the beakers each day and determine if some liquids evaporate faster than others.
In a similar vein, testing the cleaning effects of different solutions on old coins allows students to observe chemical reactions and hypothesize about how they differ between compounds. Students should first take an equal selection of tarnished or oxidized pennies, nickels, dimes and quarters. Next, they can place one of each coin into a different solution, such as dish liquid, lemon juice, water and soda. Finally, they can observe and record the coins’ reactions each day.
Examining the gas production of different liquids teaches kids about chemical reactions and the digestive process. Taking a collection of empty soda bottles, kids should add 2 teaspoons of vinegar into each one to represent stomach acids. They can then add different liquids to different bottles and place a balloon over each bottle’s top. By observing the inflation of each balloon over time, kids can determine which liquids produce more gas.