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### Chem1 Unit 1: Scientific Method and Measurements (14 days, with Earth Science)

#### Essential Questions

How do scientists prove their ideas?

#### Vocabulary

·      hypothesis – a proposed explanation that is based on observations and that can be tested

·      theory – a well-tested explanation based on observation, experimentation, and reasoning

·      law – a statement or mathematical equation that describes a basic fact or relationship found in the universe

·      controlled experiment – an experiment in which only one variable is tested at a time

·      independent variable – the variable that the scientist changes

·      dependent variable – the variable that the scientist measures; it depends on changes in the independent variable

·      control variable – any variable that is kept constant throughout the experiment

·      quantitative data – information that is collected that is numerical (e.g. time, temperature, length, mass, volume, etc.)

·      qualitative data – information that is collected that is descriptive (e.g. texture, color, odor, sound, etc.)

·      unit – quantity used as a standard of measurement (e.g. Liters, grams, meters, Celsius, etc.)

·      mass (m) – a measure of how much matter there is

·      balance/scale – a tool used to measured mass

·      gram (g)  – the metric unit of mass

·      volume (V) – the amount of space something takes up

·      graduated cylinder – a tool used to measure volume

·      Liter (L) – the metric unit of volume

·      (NOT for mastery) meniscus – the curve at the top of a liquid; volume is measured at the bottom of the meniscus

·      accuracy – how close a measurement is to the true value of the measurement

·      precision – how exact a measurement is; a more precise measurement has more significant figures

·      percent error – a quantity used to measure accuracy

·      significant figures – a way of writing data that tells the reader how precise a measurement is

·      density (D) – a property of a substance that describes how much matter the substance contains per unit volume; it has units of grams per mL (g/mL) if it is a liquid and grams per cubic centimeter (g/cm3) if it is a solid

·      conversion factor – a ratio of two different units that is used to convert from one unit to the other

·      standard notation – the usual way in which numbers are written (e.g. 6,000, 0.05, etc.)

·      scientific notation – a method of writing numbers as a base times a power of ten (e.g. 6x103, 5x10-2); it is especially useful in writing very large or very small numbers

·      (NOT for mastery) mantissa – a decimal number that multiplies by the power of ten

·      (NOT for mastery) exponent – the power of ten in scientific notation

·      global warming – the gradual increase in the average temperature of the Earth; it is cause by the greenhouse effect
·      greenhouse effect – occurs when carbon dioxide and water vapor absorb infrared radiation and also prevent some infrared radiation from escaping the Earth’s atmosphere
·      ozone – a substance in the Earth’s atmosphere that prevents some ultraviolet (UV) radiation from reaching the Earth’s surface
·      ozone depletion – the thinning of the Earth’s ozone layer, theoretically caused by chlorofluorocarbons (chemicals released into the atmosphere by coolants)
·      acid rain – occurs when nitrogen and sulfur from cars and factories combine with water vapor to make strong acids; these acids then rain down, causing chemical weathering of rocks, metal corrosion, and damage to small plants and animals

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Jun 21, 2012, 11:40 AM Emilie Siverling