Matter, Forces, Energy, Motion and Heat 8th GRADE PHYSICS Matter, Forces, Energy, Motion and Heat

READ TO STUDENTS: ALL MATTER IS COMPOSED OF ATOMS; THERE ARE OVER KNOWN 100 ELEMENTS THAT CAN BOND AND FORM COUNTLESS COMPOUNDS. REMEMBER: AN ATOM IS THE SMALLEST PART OF AN ELEMENT THAT STILL MAINTAINS ALL OF THE PROPERTIES 0F THAT ELEMENT SECTION 1: MATTER

Important Terms Chemistry- The study of the properties of matter and how matter changes. Substance- A single kind of matter that is pure and has a specific set of properties. Mixture-Two or more substances that are mixed together but not chemically combined. Mixtures can be heterogeneous or homogeneous

DESCRIBING MATTER Question: What is matter? Answer: Anything that has mass and takes up space All matter is composed of atoms Atom- The basic particle from which all elements are made Element- A pure substance that cannot be broken down into other substances by chemical or physical means.

Chemical Bond- The force that holds two atoms together Molecule- A particle made of two or more atoms bonded together Compound- A pure substance made of two or more different elements chemically combined chemical formula- A formula that gives the elements in a compound and the ratio of atoms Example: H2O C6H4O2Fe5 IF THE RATIO OF THE ELEMENTS CHANGES THEN IT IS NO LONGER THAT COMPOUND. FOR EXAMPLE, WATER HAS A RATIO OF 2 HYDROGEN ATOMS FOR EVERY ONE OXYGEN ATOM. IF THE RATIO WAS CHANGED FROM 2:1 TO 3:1, YOU WOULD NO LONGER HAVE WATER

COMPOUNDS VS. MOLECULES NOTE: ALL COMPOUNDS ARE MOLECULES BUT NOT ALL MOLECULES ARE COMPOUNDS

Matter has both physical and chemical properties

Properties of Matter Physical Property Examples Chemical Property Examples physical property- A characteristic of a pure substance that can be observed without changing it into another substance Color Size Shape Mass Density Volume Texture chemical property- A characteristic of a pure substance that describes its ability to change into a different substance Reactivity pH (is it an acid or a base) Flammability Toxicity Oxidation states Heat of combustion

MEASURING MATTER Tools of Measurement: Mass: scale or triple beam balance Length: ruler Volume: For a regular shaped object use the formula LxWxH For a irregularly shaped object use water displacement Density D=M/V

Density of a regular shaped object This block of wood has the following measurements L= 10cm W= 2cm H= 5cm Mass= 50 g In your notebook, calculate the volume, then find the density. Remember to label the units V= LxWxH V= 10x5x2= 100cm 3 D=M/V D=50/100= 0.5g/cm3

Density of an irregularly shaped object Toy Dinosaur Mass= 2mg Volume= volume with object- volume without object V=5.8mL-4.8mL= 1mL What is the density or the toy dinosaur? D=M/V D=2mg/1mL = 2mg/mL NOTE: 1mL=1cm3

CHANGES IN MATTER Matter can undergo physical and chemical changes Physical Change- A change in a substance that does not change its identity Examples: changing shape, form, state of matter Chemical Change- A change in which one or more substances combine or break apart to form new substances Examples: burning, oxidation, combustion, tarnishing, electrolysis

Chemical Changes

Physical Changes

ENERGY

ENERGY IN MATTER Key Terms: Kinetic Energy- The energy of matter in motion Potential Energy- The energy an object has because of its position; also the internal stored energy of an object, such as energy stored in chemical bonds

Forms of Energy Chemical Energy- A form of potential energy that is stored in chemical bonds between atoms Electromagnetic Energy- A form of energy that travels through space as waves Electrical Energy- The energy of electrically charged particles moving from one place to another.

Energy Transformations

WORK

SPEED, ACCELERATION, and VELOCITY

THERMAL ENERGY (HEAT)