Chemistry Experiments for Homeschoolers Physical and Chemical changes

Chemistry is a branch of science that is easier to understand with the hand’s on approach.  Thrill your children with knowledge as they complete these simple chemistry labs in your home.  

Chemical reaction – the transformation of a substance’s chemical properties into another set of chemical properties.

Bake bread.  Here is a chemistry experiment that you can use to discover chemical mysteries and then you can eat the evidence.  Use your favorite bread recipe that uses yeast.  Mix the yeast, sugar and oil in a bowl and watch it change.  Discuss the properties of chemical change.  Add the other ingredients and complete the bread recipe.  Once the bread has finished baking, review the principles of chemical reactions and then eat a slice of bread.

(Yeast is a dormant fungi that is activated by the arm water.  It feeds on the sugar.  The organism creates a gas, carbon dioxide.  The trap gas bubbles make the dough rise.)

Change change.  Fold a paper towel and pour vinegar over the paper.  Add copper pennies by placing them on top of the soaked paper towel.  Leave them overnight and watch them turn green.  

(The vinegar contains an acetate in its acid that works with the copper and forms a green covering that is made of coper acetate.)

Physical change – a change that does not change the chemical properties of the object.

Disappearing chemicals are fun and easy to do.  Dissolve 4 ounces salt into a twelve ounce clear plastic cup.  Add an equal amount of sand to the mixture.  Mix it well.  Filter the water through a coffee filter, letting it drip into another clear plastic cup.  The water will filter through but the sand will remain in the filter.  Leave the new cup in a sunny spot.  Let the water evaporate and see what you discover.

(Because salt dissolved in the water, it can pass through the filter with it.  Since the sand did not dissolve, it could not fit through.  This is a physical change because the salt remains once the water has evaporated.)

Take a simple demonstration of physical  change and make it more fun – even tasty!  Make a container of orange juice (a liquid) and pour it into ice cube trays.  Put it in the freezer and let it set overnight.  The following morning, melt one of the ice cube to demonstrate the fact that it still contains the same chemical elements.  Then, you can either eat the rest of the ice cubes or let them melt and drink them.