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DO NOW

DO NOW . Take out homework. Open to page 22 of your textbook and read through the discover activity. . Physical Change. A physical change is a change that alters the appearance of matter but does not make any substance on the matter into a different substance.

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DO NOW

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  1. DO NOW Take out homework. Open to page 22 of your textbook and read through the discover activity.

  2. Physical Change • A physical change is a change that alters the appearance of matter but does not make any substance on the matter into a different substance. • A substance that undergoes a physical change is still the same substance after the change.

  3. Changes of State • There are 3 states of matter. • Solid • Liquid • Gas • Changing from one state to another is a physical change because it is still the same substance.

  4. Changes in Shape or Form • Dissolving • Bending • Crushing • Breaking • Chopping

  5. Chemical Change • A change in matter that produces one or more new substances is a chemical change, or a chemical reaction. • In some cases one substance changes into 1 or more new substances. • In other cases 2 or more substances combine to form different substances. • Unlike a physical change, a chemical change produces new substances with properties different from those of the original substance.

  6. Examples of Chemical Changes • Burning or combustion-produces heat, light, and a new substance • Electrolysis- electricity breaks a compound into simpler parts • Oxidation- slow combination of a substance with oxygen • Tarnishing- slow combination of a bright metal with sulfur or other substance, puts a dark coating on the metal

  7. DO NOW • Take out your homework. • What parts of the experiment were examples of physical changes and which were examples of chemical changes?

  8. Law of Conservation of Mass • Matter is not created or destroyed, only changed.

  9. Matter and Thermal Energy • Energy is the ability to do work or cause change. • Every chemical or physical change in matter includes a change in energy.

  10. Temperature and Thermal Energy • Temperature is a measure of the average energy of random motion of particles of matter. • Particles of air with a high temperature have a high average energy of motion, while particles of air with a low temperature have a low average energy of motion. • Thermal energy is the total energy of all the particles in an object.

  11. Thermal Energy and Changes in Matter • When matter changes the most common form of energy released is thermal energy. • The melting of ice is an endothermic change, a change in which energy is taken in. • Combustion is an exothermic change, a change in which energy is released.

  12. DO NOW What is energy and how does it work?

  13. Forms of Energy • Forms of energy related to changes in matter may included kinetic, potential, chemical, electromagnetic, electrical, and thermal energy.

  14. Kinetic Energy and Potential Energy • Kinetic Energy is the energy of matter in motion. • Potential energy is the energy an object has because of its position.

  15. Chemical Energy • The internal energy stored in the chemical bonds between atoms is a form of potential energy that is sometimes called chemical energy.

  16. Electromagnetic Energy • Energy that travels through space in the form of waves is electromagnetic energy. • Examples of electromagnetic energy include sunlight, radiowaves, microwaves, infrared waves, and x-rays. • Chemical changes can give off electromagnetic waves and both physical and chemical changes can be caused by electromagnetic waves.

  17. Electrical Energy • The energy of electrically charged particles moving from one place to another. • Electrolysis involves electrical energy. • Two metal strips called electrodes are placed into a solution without touching. • The wires are connected to a source of electrical energy and when the energy begins to flow atoms of one kind lose electrons at one electrode and atoms of a different kind gain an electron at the other electrode.

  18. Transforming Energy • During a Chemical change, chemical energy may be changed to other forms of energy. • Other forms of energy may also be changed to chemical energy.

  19. HOMEWORK • Pg 33#1-2

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