This article includes the URL and description of 100 free web tools that can be used by all teachers. The tools are categorized into search engines, math and science, games, templates and lesson plans, and more.

This interactive Flash puzzle helps children develop number sense and an understanding of our decimal number system. A 0-99 square has been cut into 11 irregular pieces which the user re-assembles. A printable (pdf) version is included along with questions for Getting Started and a Teachers' Resources page with implementation suggestions.

Advising guidelines put together at the University of Arkansas as the undergraduate program grew and developed. Presented at the 2012 SPIN-UP conference in Austin and the PhysTEC leadership meeting at the AAPT summer meeting in Edmonton.

This iOS app requires students to use a ten frame to fill in the remaining addend with contrasting chips and then count them to tell how many more to make ten. The app can be set to build sequentially or it can be set to give random values. Additionally, the app includes an option to show number sentences when the problem is complete.

This short article suggests ten math activities which parents can incorporate into their children's summer routines to prevent loss of learning over the summer months. These suggestions can be used year round to help students develop number sense and positive connections to mathematics.

This free iOS app provides practice with multiplication facts in an arcade-like format. Students choose from among 10 levels (2 to 10 times tables and mixed times tables) and identify products of given factors in order to free trapped monkeys. Scoring rewards both accuracy and speed.

In this video segment from Cyberchase, the CyberSquad replaces a piece of track to get the Madre Bonita Express to the Mother's Day harvest.

The transit of Venus is a rare astronomical event that has been well documented throughout history. The most recent transit occurred in June of 2004, and the one before that took place more than 100 years earlier in 1882. This site from the South African Astronomical Observatory provides information and first-hand observations of the 1882 event from Wellington, South Africa. Just prior to the event, an observatory was erected at the Huguenot Seminary for girls, and some of the historical observations made from that site in 1882 are provided here for your perusal.

This page from the Volcano World website contains a summary account of the 1959 eruption at Kilauea Iki which is illustrated by photographs and videos.

This video adapted from the Valdez Museum & Historical Archive, explores what happened during the Great Alaska Earthquake of 1964 through original footage, first-person accounts, and animations illustrating plate tectonics.

An exercise on the effects of flooding that took place in the upper Mississippi River drainage basin in 1993, using before and after satellite images.

This dataset, created by Robin H. Locke of St. Lawrence University, describes 93 new cars for the 1993 model year with 26 variables, including price, mpg ratings, and engine size. It also illustrates a broad range of statistical techniques such as box-whisker plot, confidence intervals, difference in means, one-way ANOVA, contingency table, scatterplot, regression, and correlation. If further research is required the author has included a list of references.

This movie shows a total eclipse of the Sun which occurred in 1994. It is accompanied by a link to a written description of the Sun's physical characteristics.

This simulation shows time-dependent 1D quantum bound state wavefunctions for a number of different wells. Position, momentum, parity, energy, and current can all be viewed, with phase shown with color. Eigentstates can be selected using the energy level diagram. Multiple-energy-eigenstate wavefunctions can be created through changes in the amplitude and phase of the basis states using spinors. Postion and energy measurements can be taken, resulting in new states of the system.

This simulation explores the transitions between quantum states in a number of 1D systems. The time-dependent wavefunction is displayed. An electric field resonant with the transition between states is applied and the changes in the wavefunction with time are tracked. The dipole transition probability is displayed for different initial to final state transitions, and the user may select the transition they wish to observe.

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: First pose the question: Here are four triangles. What do all of these triangles have in common? What makes them different from the figures that are no...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * A copy of Grandfather Tang's Story by Ann Tompert * One set of tangrams for each student (see note in commentary) * A set of tangrams for t...

3D interactive model of 1H-indene C₉H₈ for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1H-pyrazole C₃H₄N₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1H-pyridine-2-thione C₅H₅NS for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1H-pyrrole C₄H₅N for demonstrating molecular geometry, vibrations, symmetry and orbitals.

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials - 2 clear plastic cups for each pair of students - 4 bean seeds for each pair - soil - unifix cubes - a plant or math journal to record data ...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * Completed monthly weather recording sheet * Crayons * Sentence strips with frames (see below) * Student worksheet Actions Every day for a m...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials A spinner with the numbers 0, 1, 2, ... 9 A spinner with the decades 00, 10, 20, ... 90 Math journal or teacher-made worksheet Pencil Actions...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials For each pair: * 2 ten-sided dice with the numbers 0 to 9 or two spinners with the numbers 0 to 9 * Base-10 blocks, linking cubes, or bundled...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials Set of cards from 1-100, these can be purchased or created using a black marker and index cards Setup Sort the 1-100 cards into sequential gr...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials 20 counters or linking cubes per pair of students pencil copy of the problem Actions The teacher poses the problem: Bo bought 20 tickets to p...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * A cup for each student to represent his/her cave * Counters * Recording sheet Actions The teacher begins by counting out a certain number o...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials A large set of dominoes to affix to a whiteboard or place in a pocket chart, or a regular set to use on a document projector. One set of domi...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * Fact Family work sheets * Blank addition and subtraction frames (2 of each) * Numbers cards in fact-family sets Actions As a whole class, t...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Write as many equations for each picture as you can. Use the numbers 4, 1, and 5. Here are some equations for this picture. 4+1=5 \hskip4em 5 = 4+1 5-1...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * Link-cubes or snap-cubes (2 colors for each student or pair of students) * A die * Paper and pencil Actions 1. Roll the die. 2. Using a sin...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials * Unifix cubes * Large blocks in different sizes or varying lengths of sentence strips Note: The large blocks or the cut-up lengths of senten...

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Materials The Very Hungry Caterpillar by Eric Carle The students work individually or in pairs. Each student or pair needs: Three ten-frames for each s...

3D interactive model of 1R_2S-1_2-diaminocyclohexane C₆H₁₄N₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1R_2S-1_2-dimethylcyclopentane C₇H₁₄ for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1R_3S-1_3-dimethylcyclopentane C₇H₁₄ for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1R-camphene C₁₀H₁₆ for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1R-camphor C₁₀H₁₆O for demonstrating molecular geometry, vibrations, symmetry and orbitals.

3D interactive model of 1S_2R-1_2-diphenylethane-1_2-diol C₁₄H₁₄O₂ for demonstrating molecular geometry, vibrations, symmetry and orbitals.