Unit+1+Vocabulary

The key terms listed and defined below are an important part of this unit.

1. **Scientific inquiry** is way of making sense of the world by asking testable questions, designing systematic investigations, and interpreting findings. (Latin //inquirere//, “to seek.”) 2. An **observation** is a statement recorded by a scientist that describes the world using the five senses (seeing, hearing, smelling, tasting, or touching) and scientific instruments. 3. **Quantitative** observations and data are numerical and measureable (think “quantity”). 4. **Qualitative** observations and data are difficult to measure or count and are described using words and pictures (think “quality”) 5. **Phenomenon** is an event or occurrence that is observable. 6. An **experiment** is a systematic method of investigation that often involves testing a prediction and looking for cause and effect. 7. **Data** are collected observations and measurements (singular: datum). 8. **Empirical** describes data gathered by scientists during experimentation. 9. **Hypothesis** is a prediction or explanation that can be tested and that is based on observation, research, and prior knowledge. 10. **Inference** is conclusion drawn based on observations and prior understanding. 11. A **testable question** is answered by collecting and analyzing data and developing explanations based on the data. (Questions that cannot be answered through scientific investigation are those that relate to personal preference, moral values, or the supernatural.) 12. **Chemistry** is the science concerned with the composition, structure, and properties of matter. 13. **Substance** is a material with a specific chemical composition. 14. **States of matter** are the physical forms (solid, liquid, and gas) in which a substance can exist. 15. **Density** is the ratio of the mass to the volume of a substance. 16. **Matter** is anything that has mass and takes up space. 17. **Mass** is a measure of the amount of matter in an object (grams). 18. **Volume** is a measure of the amount of three-dimensional space an object takes up (liters or m3). 19. **Meniscus** is the curve at a liquid’s surface often seen when using a measuring cup or beaker. 20. **Density** is the ratio of the mass of a substance to the volume of substance (grams/liter or grams/m3). 21. **Physical property** is a characteristic of a substance that can be observed or measured without changing the matter’s identity (such as thermal conductivity, state, density, solubility, ductility, or malleability). 22. **Physical change** occurs when natural or human actions alter one or more physical properties of a substance. 23. **Chemical property** is an ability of a substance to change into new matter with different properties. 24. **Chemical change** occurs when substances are altered and a new substance is formed with different physical and chemical properties. 25. The **composition** of a substance is the type of matter that makes up a substance and the way that the matter is arranged in the object. 26. **Solid** is the state of matter in which the volume and shape of a substance are fixed. 27. **Liquid** is the state of matter in which the volume of a substance is fixed by the shape is not. 28. **Gas** is the state of matter in which neither the volume nor the shape of matter is fixed. 29. **Surface tension** is the cohesive force that acts on the surface of a liquid when molecules are attracted to one another. 30. **Viscosity** is the resistance of a liquid to flow. 31. **Pressure** is the amount of force exerted per unit area of a surface. 32. **Temperature** is a measure of how fast the particles in a substance are moving. 33. **Boyle’s law** states that the volume of a gas is inversely proportional to the pressure of a gas when temperature is constant. 34. **Charles’s law** states that the volume of a gas is directly proportional to the temperature of a gas when pressure is constant. 35. **Change of state** (or phase change) occurs when a substance gains or loses energy and takes on a new physical form. 36. **Melting** is a change in state in which a solid becomes a liquid by adding energy. 37. **Evaporation** is a change in state in which a liquid becomes a gas by adding energy. 38. **Boiling** is a conversion of a liquid to vapor by adding energy. 39. **Condensation** is the change of state from a gas to a liquid by removing energy. 40. **Freezing** is a change of state from a liquid to a solid by removing energy. 41. **Sublimation** is a process in which a solid changes directly into a gas.