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Main Curriculum Tie:
Background For Teachers:
When seltzer tablets and water are mixed together they create a chemical reaction. These two substances create carbon dioxide. In this activity students will understand that matter is neither created nor destroyed. It has changed from one substance to another.
This is the reason for using the scales to measure the matter. The weight should be the same before and after the experiment. The chemical change is known as the Law of Conservation of Matter. Matter can neither be created nor destroyed. It can only change from one substance to another.
Measuring all substances before and after the reaction will help students confirm predictions and draw conclusions about the “Law of Conservation of Matter.”
In the second part of this activity you will be using plaster of Paris, which originated in Montmartre Paris. Plaster of Paris is formed from gypsum. The gypsum is heated to 150 decrees Celsius and becomes a dry powder. When this powder is mixed with water it re-forms into a paste and eventually hardens into a solid. The powder mixed with water is held together by hydrogen bonds in the water molecules. This is a week bond that is easily broken. That is why Plaster of Paris is quite soft.
When Plaster of Paris and water are mixed together they undergo a chemical change. The particles rearrange to make a completely new substance. When plaster of Paris and water are mixed together the mixture becomes warm releasing energy in the form of heat therefore undergoing a chemical change.
Warning: Plaster of Paris should never be dumped down a sink or toilet. It always hardens and will cause major problems with plumbing.
Intended Learning Outcomes:
Predict what you think will happen when vinegar and baking soda are mixed together in a bottle with a balloon attached to the top. Do you think that the mass of the objects will be the same or different after performing the experiment? Does this experiment support the “Law of Conservation of Matter?”
Instructional Procedures-Part One
Instructional Procedures-Part Two
Corcoran, Carol A.; (May-Jun 2004). A teacher’s guide to alternative assessment: Taking the first steps. Clearing house, Volume #77 (Issue #5), Page #213.Hands-on learning is critical to students’ understanding of science concepts. Research shows that hands-on projects actually help children learn better. Hands-on learning helps students more readily understand concepts and boosts their self-confidence.
Performance Assessment is the collection and evaluation of evidence of student learning, focusing on indicators of meaningful and valuable student progress. This type of assessment asks students to perform, create, produce, or do something. Performance assessment moves the students into higher-level thinking and problem-solving skills. It uses tasks that represent meaningful instructional activities involving real world applications and using human judgment to do the scoring.
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