The Volcano

• The volcano experiment is a classroom favorite that is sure to impress the kids, but it takes some time to set it up for maximum effect.
  
  Using modeling clay, form a mound in the shape of a steep-banked volcano and hollow out a crater at the peak of the mound. You may want to paint the clay to look like rock or trees to make it more realistic, and you may also wish to put some red around the edge of the crater so it looks like lava trickling down the side before the main eruption.
  
  Place one tablespoon of baking soda inside the crater and add a few drops of red food coloring and a few drops of liquid dishwashing soap to thicken your "lava." Add a quarter cup of vinegar to the crater to cause the eruption, according to Kids-science-experiments.com.
  
  When the vinegar and baking soda mix, hydrogen in the vinegar reacts with the bicarbonate in the baking soda to make carbonic acid, which immediately turns into carbon dioxide and water.
  
  

Shine the Coin

• Although not as impressive as the volcano, this is a quick and easy way to show a chemical reaction that happens right before the eyes.
  
  Fill a glass with lemon juice and locate a dirty penny. Drop the dirty penny in the lemon juice and let it soak for 10 minutes. Remove the penny from the juice, place it on a paper towel and watch it return to its mint condition.
  
  The first reaction is between oxygen and copper. The air itself "oxidizes" the coin and makes it dirty and corroded. The acidic lemon juice reacts with the oxidation coating on the coin and removes it. The result is a shiny copper penny.
  
  

Steel Wool Heater

• For this experiment, place a mercury thermometer in a jar with the lid on and measure the temperature inside the jar five minutes later and write it down. Remove the thermometer from the jar and soak a piece of steel wool in vinegar for one minute. Squeeze the vinegar out of the steel wool and place it in the jar. Place the thermometer back into the jar with the bulb shoved down into the steel wool and put the lid back on for five more minutes. Remove the thermometer and record the new temperature. It will have risen noticeably.
  
  The vinegar does not cause the reaction here exactly. The vinegar removes the protective coating on the steel wool, which allows the iron to rust very quickly when exposed to oxygen. When the iron in the steel wool reacts with the oxygen in the jar, it causes heat to be released, forcing the mercury up, according to Reeko's Mad Scientist Lab.