1. boiling point boiling point: the temperature at which a substance changes from a liquid to a gas The BOILING POINT of pure water is 100° Celsius.

2. conductor conductor: a material that allows heat energy, electricity, or sound to pass through it easily Speaker wire CONDUCTS sound. Copper is a good CONDUCTOR of heat. Saltwater is a CONDUCTOR of electricity.

3. density density: the amount of mass in a known volume of an object or substance density blocks density of liquids

4. dissolve dissolve: to form a solution with another substance Particles of 1 or more substances are evenly distributed in another to form a solution. The antacid tablet is DISSOLVING in water.

5. electrical energy electrical energy: a form of energy that consists of a flow of electric charges through a conductor

6. freezing point freezing point: the temperature at which a substance changes from a liquid to a solid Metal melts and freezes at a much higher temperature. The FREEZING POINT of iron is 1535° Celsius! The FREEZING POINT of pure water is 0° Celsius. Water also begins to MELT at 0°.

7. insulator insulator: a material that does not let heat energy, electricity, or sound pass through it easily Styrofoam is a good INSULATOR of heat energy.

8. magnetism magnetism: a force that pulls magnetic materials across a distance

9. mass mass: the amount of matter in an object or substance

10. matter matter: the material, or "stuff," that everything is made of MATTER can be classified into three states: solid, liquid, and gas.

11. mixture mixture: a combination of two or more substances that can be separated by physical means This fruit salad is a MIXTURE of blueberries, raspberries, strawberries, cantaloupe, and honeydew melon.

12. physical property physical property: a property that can be observed, measured, or changed without changing the substance itself PHYSICAL PROPERTIES, or characteristics, of matter can be observed with your five senses.

13. solubility solubility: a measure of how much of one substance will dissolve in another substance Copper Sulphate powder is SOLUBLE in water. These plant-based dyes are SOLUBLE in water.

14. solution solution: a mixture with one substance spread out evenly in another substance so that you cannot tell the two substances apart Soda is a solution made up of water, sugar, flavorings, and gas. Lemonade is a SOLUTION made up of water, sugar, and lemon juice.

15. thermal energy thermal energy: the amount of energy in moving particles of matter; heat Propane gas burners produce the THERMAL ENERGY that allows hot air balloons to rise.