Lecture # 27 SCIENCE 1 ASSOCIATE DEGREE IN EDUCATION MATTER

What is matter? Begin with an activity that helps Students review the distinctions between substances and mixtures. Next, review the idea that each substance has a characteristic set of chemical and physical properties. Then review the concept that mixtures can be separated by physical means but substances cannot. Introduce the model of the atom. Inform Student Teachers that it is composed of protons, neutrons, and electrons. You can do this in combination with introducing the periodic table. Describe how the periodic table evolved over time. Explain how the views of science constantly change based on new work, discoveries, and enhanced theory.

A hands-on inquiry activity Place Students in groups and give each group a mystery bowl (solids) and a mystery flask (liquids). Ask them to identify and sort the mystery substances into as many components as possible. Have them document their findings. Provide them with any ‘lab tools’ that you have available (for instance, funnel, sieve, different-size containers, magnifying glass, heat source, magnets, etc.).

For the solid mystery, you can use organic and inorganic materials that you find around the house and school, such as: 1.Branches 2.Fruits 3.Soil 4.Stones 5.Rusty nails 6.Plastics 7.Matches. For the liquid mystery, you can use: 1.Water 2.Oil 3.Vinegar or alcohol 4.Sugar or salt dissolved in the solution. A hands-on inquiry activity

PURPOSE OF THIS ACTIVITY The purpose of this activity is not for Students to identify each component that you added to the mixtures. Instead, they start using physical means to separate the mystery substances. They realize that mixtures can be separated and sorted into very small components. When they have made considerable progress, challenge them by asking whether they can find more components by looking at smaller items. For instance, the branches can be broken into smaller pieces, but how small can they get? What happens when you look at the rusty nail? What is it made up of ? Encourage them to record their thinking, methods, and findings. Ask them to list the properties of each component that they isolated as best as they can. You might have to revisit the concept of physical properties and provide them with some examples.

FINAL CLASS DISCUSSION In a final class discussion, guide Students in revisiting physical properties (and, if applicable, chemical properties). They do not need to physically separate all the mixtures. They should not conduct any chemical separation at this point. The goal is to construct a mental model that you can keep separating a substance using physical and chemical separation. They should also recognize that if you keep separating a substance, you can identify a compound or element that makes up the mixture.

During the final discussion, create an overview chart listing the identified physical and chemical properties of the identified substances. Students should be able to list physical properties. Have them explain and list how those properties can be used for physical separation. At this point, it is enough if they have a vague conceptual understanding of chemical properties and how they can be used for chemical separation. They do not have to be able to explain this yet on the atomic level. FINAL CLASS DISCUSSION continue ……..

Additional Activities Conduct an electrolysis of water. Then have your Students test the products of the electrolysis (oxygen and hydrogen) for their properties and contrast them with the properties of water. Focus the discussion on how properties change dramatically when a substance undergoes a chemical reaction. Discuss how that differs from a substance undergoing a physical change. Without going too deep into molecular theory, begin to discuss why those properties changed.

Additional Activities continue ….. Students explore chemical change and chemical reactions in more depth. For now, it is enough for them to understand that certain substances have unique properties. They should know that if substances undergo a chemical change, particles are rearranged on the atomic level; therefore, the properties of that substance also change.

The challenge: a mystery substance (for instance, white powder) was found in an envelope mailed to a celebrity. The substance was sent to a crime lab for identification. How can scientists identify what the powder is? How can they go about finding the answer? Guide Students through their hypotheses and speculations. Encourage them to argue their points based on their scientific prior knowledge or common sense. Lead the discussions towards the point that substances can be separated, and then properties of the substances can be identified through a series of specific tests. Once the properties of the substance are established, the substance can be identified. Additional Activities continue …..