Children can read about chemical reactions in their science textbooks, but they don't always understand the concepts. Fortunately, hands-on science experiments give students a visual lesson so that they can see the chemical reactions for themselves. One experiment you can implement is turning your average chicken egg into a rubber ball that actually bounces when tossed on a school desk. This will show the students how the acid in household vinegar reacts with both the egg's shell and the egg's inner membrane.
Place one egg for each student in a large pot. Cover the eggs with water. Turn the stove to high heat and boil the eggs for a total of 12 minutes.
Drain the water from the pot and allow the eggs some time to cool off.
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Give each student a cup and instruct the students to place the cooled egg in the cup. Pass around vinegar and have the students pour the vinegar in the cup until it covers the egg.
Set the cups aside for 48 hours. Then drain the vinegar out and have the students examine the eggs. The children should notice that the eggshell has completely dissolved. The acid in the vinegar reacted with the calcium of the eggshell and ate away at it until it was gone.
Instruct the children to place their eggs back in the cups and once again fill each cup with vinegar. Wait two weeks this time before allowing the children to drain the vinegar from the cups. The vinegar will then seep into the egg's membrane, turning it into a rubber-like substance. Give the students time to examine their new rubber ball eggs. The eggs feel like rubber balls and they bounce just like rubber balls do, too.
If you perform this experiment with an egg that is not hard boiled, you won't be able to bounce the egg, but you will be able to see through the egg.