This interactive animation takes the fear out of reference frames, and it's fun. All motion is relative to a frame of reference. This resource shows how the motion of a bouncing basketball looks different depending on whether the observer is standing still, walking in the same direction as the player, or walking in the opposite direction. It offers students nine scenarios (frames of reference), and they must answer questions from the observer's viewpoint.  (Open Website)

When introducing frames of reference, it helps if your students have a sense of scale. In this wonderful update of "Powers of 10", your students view images of the Milky Way at 10 million light years from Earth, then move through space at successive orders of magnitude until they reach an oak tree in Florida. After that, the applet decreases in progression down to molecular structure of one leaf, and on to chromatin, DNA, and subatomic particles.  (Open Website)

If you've never visited the award-winning Hyperphysics web site, put it on your list. It is a set of online tutorials that features concept maps laid out in a web-like fashion for easy navigation. This page describes units of measurement, unit conversions, dimensional analysis, and basic mechanical quantities. Some of the maps are "active graphics", which link to capsules of background information. Remarkably easy to use!  (Open Website)

As the name implies, this web page offers non-scientists a guide to SI. The materials are written so that a user with little prior experience with metrics can comprehend the measurements and how they are applied mathematically.  ***NOTE: This is a 1.5MB download.  (Open Website)

This item provides rules and "how-tos" for calculating both the relative and absolute uncertainty in a measurement.  (Open Website)

This resource is a digital tool for performing unit conversions with the extra feature of displaying cancellation of terms, helping students to gain a deeper understanding of the mathematical processes involved.  Students can convert among 25 physical quantities, including units such as force, temperature, energy, and current.  (Open Website)

Information at the foundation of modern science and technology from the Physics Laboratory of NIST  (Open Website)

This comprehesive guide on SI encompasses tables, charts, drawings, and a coherent set of text explanations of base units, derived units, common quantities, equivalencies, and prefixes.  It is written so that a user with no prior experience with metrics can comprehend the measurements and how they are applied mathematically.  (Open Website)

Teachers will find in-depth information on base units, derived units, and relationships among SI units in this free web site developed and maintained by NIST (the National Institute for Science and Technology). Don't miss the link to the "Digital Dutch" unit converter.  It is amazingly easy to use.  (Open Website)

This 3-day inquiry-based lesson is a great way for students to discover what "accuracy" and "precision" mean in measurement. Fun hands-on activities include measuring objects using ancient "cubit" units and tossing foam darts to gather data. The lesson concludes as students work cooperatively to explore using significant figures in an Internet project.  (Open Website)

This cost-free web page allows teachers and learners to easily create and print graphs for use as visual communication tools.  With one mouse click, the students may choose from five graph types: bar, line, area, pie, and X/Y.  Various patterns, colors, grids, and label choices are available to allow customization.  (Open Website)

Accurate measurement is important in physical science, but no measurement is absolutely precise. If we assign any two people to measure the same object, there will always be a slight difference.....even if it's only a fraction of a centimeter. In physical science, this is called "uncertainty". This is a great resource to help teachers and students understand the role of error in measurement and how it can affect the results of an experiment.  (Open Website)

Converting between units doesn't have to be frustrating to your students. This tutorial, part of an award-winning collection, is the best we found for demonstrating how to use unit cancellation to solve problems involving unit conversions.  (Open Website)

This digital unit converter offers students more than the typical online conversion resource.  It allows conversion among 25 physical quantities, from more common applications (force, energy, current, voltage) to lesser-used conversions such as illuminance and magnetic flux.  It provides the additional feature of displaying cancellation of terms, helping beginners to gain a deeper understanding of the mathematical processes involved.  (Open Website)

This resource is a comprehensive guide on SI for teachers and students.  It contains tables, charts, and text explanations of base units, derived units, equivalencies, common quantities, and prefixes.  To aid the learner in visualizing quantities, drawings of common multiples are provided for each of the base units.  The materials are written so that a user with no prior experience with metrics can comprehend the measurements and how they are applied mathematically.  (Open Website)

A helpful online unit converter for teachers and students.  (Open Website)

This cost-free web page allows teachers and learners to easily create and print graphs for use as visual communication tools.  With one click, the students may choose from five graph types: bar, line, area, pie, and X/Y.  Various patterns, colors, grids, and label choices are available to allow customization.  (Open Website)

Here is a set of free assessment tools for grades 6-12 on topics that cover force and motion, waves, properties of matter, and chemistry.  Diagnoser assessments are aligned with NSES standards and Benchmarks, and include elicitation (warm-ups) and developmental lessons.  After completing the lesson, Diagnoser provides a computer program that poses questions and feedback for students via the internet.  The final step in the process is "Prescriptive Activities", designed to target specific problematic areas located by Diagnoser.  (Open Website)

Your students will need to understand how to cancel units before they can solve problems using dimensional analysis. Beginning with simple one-step conversions, it progresses to problems requiring multiple conversions. Students will like the informal writing style by the author, whose motto is "If I can do this stuff, then so can you!"  (Open Website)

Students explore size estimation in 1, 2, and 3 dimensions. Multiple levels of difficulty allow for progressive skill improvement.  (Open Website)

An updated version of "Powers of 10".  View the Milky Way at 10 million light years from Earth, then move through space at successive orders of magnitude until you reach an oak tree in Florida. After than, move from a single leaf to the cell nucleus, chromatin, DNA, and subatomic particles.  (Open Website)

Interactively explore various specimens as they appear under a scanning electron microscope (SEM).  SEM can produce very high-resolution photos of details as small as 1-5 nanometers. Students can adjust the focus, brightness, and contrast, and choose from a cockroach, pollen grain, diatom, a gecko foot, a jellyfish, and more. Each successive image doubles the magnitude of the magnification.  (Open Website)

The National Assessment of Educational Progress (NAEP) is the only nationally administered, continuing assessment of what America's students know and can do in various subject areas.  This website provides free access to the most recent assessment questions, organized by topic and level. Teachers can view an analysis of the results to see short-term and long-term trends in samples of students at ages 9, 13, or 17 years.  (Open Website)

Here is a set of free assessment tools for grades 6-12 on topics that cover force and motion, waves, properties of matter, and chemistry.  Diagnoser assessments are aligned with NSES standards and Benchmarks, and include elicitation (warm-ups) and developmental lessons.  After completing the lesson, Diagnoser provides a computer program that poses questions and feedback for students via the internet.  The final step in the process is "Prescriptive Activities", designed to target specific problematic areas located by Diagnoser.  (Open Website)