Measurement is fundamental to science and engineering. It is also essential in our everyday lives. No matter what it is you are attempting to measure—distance, time, heat, or weight—a tool or instrument exists to help you do it. Rulers help determine length. Clocks mark time. Thermometers express temperature. And scales calculate weight or mass. To obtain the most precise measurements needed for specialized research, more advanced tools have been developed that might not be commonly available. For instance, an atomic clock measures time more accurately than a wristwatch, hourglass, or sundial.

Unlike in ages past, when units of measurement evolved to suit local commercial or political needs (the yard, for example, needed to measure wool, was defined as the distance from the king's nose to his outstretched middle finger), today we have a global standard of units. The metric system is the standard measurement system in science that directly relates length, volume, and mass to each other. As it is a decimal system, conversions and calculations are relatively simple.

Science is a process for acquiring knowledge that depends on making careful observations of objects and events in our universe and on forming theories that explain these observations. Measuring the things we observe allows us to make comparisons with respect to size, distance, speed, and other physical and chemical properties. To measure size and distance, scientists and engineers use the fundamental property length, which is the measurement of space in any direction. To calculate speed, one can measure distance covered and the time it takes to cover it, then divide the former by the latter to arrive at a measurement that can be represented either in kilometers (or miles) per hour, or meters (or feet) per second.

To determine what makes a waterslide great, the girls in the video start off by measuring the speed a rider attains on each of two waterslides. By determining the distance and then timing the duration of the ride, they calculate the speed. Because certain factors such as flow of water might not be constant, they repeat the measurements and determine an average ride time. Averaging can improve the accuracy of measurements.

Because "wildness" is not an objective measurement for which standards have been established, there is no standardized tool to measure how wild a waterslide is. Valerie and Margie determine that a ride's wildness corresponds to a rider's ability (or inability) to stay within the lines of a circular maze, so they develop their own tool to measure this. They call their homemade tool a "mazometer." Through the years, scientists have invented tools like the mazometer when no other tool existed to help them better understand the natural world. Later, standards were often developed based on the new tool.

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