Terminal Velocity Investigating Forces and Motion in our Universe Expedition 1 The Quest for Exactness

Objectives To accomplish your expedition goal successfully, you will need to Evaluate systems and standards of measurement. Use measurements to describe objects in your environment. Discover why SI units are critical for communication among scientists, engineers, industrial partners, and societies. Explore how measurements derived from SI units can be used to further describe your physical environment. Compare accuracy and precision when analyzing measurement results. Assess how technological advancements to measurement tools impact society.

A model is any representation of an object or event used to explain the natural world.

When a scientist or engineer collects data, the information is generally first put into a data table

Scientists use graphs to turn these raw numbers into a visual representation. Common graphs include line, bar, and circle graphs.

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Measurement uses numbers to describe processes and events.

Length – the distance between two points, Time – the interval between two events

Mass – the amount of matter in an object Temperature – the amount of energy within a sample of matter

Electric current – the flow of charges Amount of a substance – the number of atoms or molecules in a sample of material, and

Luminous intensity – the measure of light intensity coming from a source. Metrology is the study of measurement.

An estimate is an approximate measurement of an object or event

The Metric System The Metric System is a base-ten system

SI units are the current world standard for measurement. There are seven basic SI units. They are the meter, kilogram, second, ampere, kelvin, mole and candela.metersecondampere kelvincandela

Each unit is used to measure a particular quantity Additionally, SI units can be combined to describe area, volume, density, speed, and acceleration.

Scientific prefixes allow us to reduce the number of zeros and make the figures more manageable. For example, 54,500,000,000 meters = 54.5 giga-meters, and 400,000,000,000 meters = 400 gigameters

Converting Metric Units When you are converting from a big unit (like kilometers) to a smaller unit (like millimeters), you multiply. When you are converting from a small unit (like millimeters) to a larger unit (like kilometers) you devide.

U.S.Customary UnitsU.S.Customary Units- used in only 3 countries? The U.S. ______________, and ___________

Derived units use more than one measurement at a time. Some examples include area, volume, density, speed, acceleration, and weight. Area is the size of the surface of a two-dimensional object.

Volume is the amount of space something takes up.

Your body displaces, or pushes out, an amount of water equal to the volume of your body below the water line.

Speed is the change in distance over time. Speed Accelleration is the rate of the change in velocity.

Weight is the force exerted on any object with mass by the gravitational acceleration of a body such as a planet.force

Mass is the amount of matter in something. Matter is anything that has mass and takes up space.

Density is the amount of mass in a given volume. All solids, liquids, and gases have density. densities can be affected by temperature and pressure.

Knowing an object’s density allows you to predict whether the object will float or sink.

Errors in Measurement A standard is a benchmark used to compare other measures. Calibration is the process of determining how close a measured result is to the true value.

Accuracy is how close your measurement is to the actual value. Precision is how close a group of measurement s are to each other.

Accuracy is how close your measurement is to the actual value. Precision is how close a group of measurements are to each other.

Significant digits describe how precise a number is. There are several rules to follow when counting significant digits. Class rule- only use 2 decimal points (unless otherwise instructed) Which ruler will result in greater precision if used to take repeated measurements? Why?