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Goals:
1. Students will acquire a knowledge of what scientific “matter” is and how scientists study matter in scientific inquiry to understand our world and the universe.
2. Students will understand the difference between physical properties and chemical properties of matter.
Objectives:
1. Students will understand what the scientific term “matter” is.
2. Students will understand the three basic forms of matter .
3. Students will be introduced to the difference between physical properties and chemical properties of substances.
4. Students will understand density, hardness and brittleness of solids.
5. Students will learn about Friedrich Mohs and the Mohs scale of hardness.
1. matter (definition from freedictionary.com)
a. Something that occupies space and can be perceived by one or more senses; a physical body, a physical substance, or the universe as a whole.
b. Physics Something that has mass and exists as a solid, liquid, gas, or plasma.
2. Solid: one of the three physical forms of matter, having a solid shape and form, not liquid or gaseous.
3. Liquid: a substance(one of three physical forms of matter) which flows easily and is not solid or gaseous.
4. Gas: a substance (one of three physical forms of matter) which is completely fluid and has no definite shape or volume.
5. Element: basic chemical substance, e.g hydrogen, oxygen, (in specific combinations form compounds).
6. Compound:a chemical substance made up of two or more elements. e.g H20 (water)
7. Chemical: a substance formed by reactions between two elements.
8. Chemical properties: a property used to characterize materials in reactions that change their identity.
9. Substance: a chemical substance is a material with a specific chemical composition.
10. Fre:idrich Mohs: an Austrian mineralogist who invented the Mohs scale of relative mineral hardness.
11. The Mohs Scale: a measurement scale of 10 common substances ranked as to how “hard” they are.
12. Plasticity: the capability of being formed or molded; the quality of being plastic.
13. Brittleness: firm and solid, but easily broken by force
14. Hypothesis: hypothesis is an explanation which can be tested in some way which ideally will either proves or disproves the hypothesis. It is a scientific question that we ask about a problem or a scientific phenomenon that we then attempt to find an answer to by conducting scientific experiments.
15. Experiment: conducting scientific tests in an attempt to prove or disprove a hypothesis.
Session 1: 30 minutes: Discussion and introduction of matter.
Student will discuss what they think they know about matter with leader/teacher. Students will be directed to check out the website describing basic matter in its three forms: liquid, solid and gas.
Have students make a chart on paper with the three headings of liquid, solid and gas and begin to list items that fit those categories. Prompt as needed. Provide students with the book: What is Matter by Don Curry. Have students read from the book in silent reading time. Ask them to find items that are solid to be tested in session three for hardness and brittleness, plasticity.
Provide students with vocabulary handout listing the words to be learned and ask them to look up the meanings in the dictionary as “homework”.
Session 2: 30 to 45 minutes Vocabulary review and introduction of physical properties and chemical properties of substances
Review vocabulary words to see if students have discovered the correct definitions. Discuss the terms as needed, offering explanations and examples. Offer the following information in lecture form during the discussion.
Lecture notes for session 2:
Every substance in our world is made up of what we call “chemicals”. Every chemical has its own unique characteristics. Some are physical things that we can see and feel, such as color, hardness, texture. We can look at every item in our world like the desk we sit at, or the water we drink and ask some basic questions about each of them to understand how they exist in our world. Some common questions we might ask about any substance or thing could include the following: (write these on chalkboard or have them in a handout to distribute to student)
Physical properties of substances:
1. Is is liquid, solid or gas?
2. What color is it? Is it shiny or dull? Is it rough or smooth? Can we see through it(transparent) or is it solid? (opaque)
3. Is it a powder or crystal?
4. Can it be stretched or bent?
5. Does it break rather than bend?
6. If we squash it or stretch it, does it return to its original shape (elasticity)
7. How hard is it? (hardness)
8. How heavy is it?(density)
9. Does it float?(buoyancy)
Chemical properties are the way chemicals react together and are not as easy to see as physical properties.
Chemical properties take place in the world all around us all the time. When your mother bakes a cake, chemistry is occurring. You start with basic substances like flour, eggs, water, milk (each with it's own chemical make-up) and when you combine them into a mixture, they are changed. How do they change? (discussion of how those ingredients dissolve and combine together)
But when you add heat (the oven) the mixture changes into something completely different than the original ingredients. This is what happens when we begin to study chemistry and learn how various elements combine together to create completely different substances. Some of these are hard to see. They occur as a microscopic level.
Homework or additional study before session three: Students should take their list of substances and for the items that are solid, have them answer the physical properties questions. Note to them that some of the questions like how hard is it or how heavy require them to experiment on the item, which is what we will do in session 3, when students will learn about physical properties of plasticity and hardness.
Session three: Experiment on solids for plasticity and hardness
Collect test solids ahead of time and have students gather or bring test solids to session three. Make sure all students have protective goggles and have been given good safety instructions.
Review physical properties list and then explain that today they will test some of their items to discover facts about two physical properties; plasticity and hardness.
Lecture Notes for this session:
Some substances are hard but will still break easily. Some are very difficult to break but they may bend or squash together. Some substances won't bend or squash and in fact will crack if it too hard. These substances are called brittle substances. Our first experiment today will be to test to see how brittle some of our solids are.
