Solve an inequality involving absolute values using a graph of the absolute-value function. Vary the terms of the absolute-value function and vary the value that you are comparing it to. Then explore how the graph and solution set change in response.

Absolute Value Equations and Inequalities

Solve an inequality involving absolute values using a graph of the absolute-value function. Vary the terms of the absolute-value function and vary the value that you are comparing it to. Then explore how the graph and solution set change in response.

Follow in the footsteps of Edwin Hubble to discover evidence supporting the Big Bang Theory. First, observe Cepheid variable stars in different galaxies to determine their distances. Then, measure the redshift from these galaxies to determine their recessional velocity. Create a scatterplot of velocity vs. distance and relate this to an expanding universe.

Big Bang Theory - Hubble's Law

Follow in the footsteps of Edwin Hubble to discover evidence supporting the Big Bang Theory. First, observe Cepheid variable stars in different galaxies to determine their distances. Then, measure the redshift from these galaxies to determine their recessional velocity. Create a scatterplot of velocity vs. distance and relate this to an expanding universe.

Construct a box-and-whisker plot to match a line plots, and construct a line plot to match a box-and-whisker plots. Manipulate the line plot and examine how the box-and-whisker plot changes. Then manipulate the box-and-whisker plot and examine how the line plot changes.

Box-and-Whisker Plots

Construct a box-and-whisker plot to match a line plots, and construct a line plot to match a box-and-whisker plots. Manipulate the line plot and examine how the box-and-whisker plot changes. Then manipulate the box-and-whisker plot and examine how the line plot changes.

Construct a DNA molecule, examine its double-helix structure, and then go through the DNA replication process. Learn how each component fits into a DNA molecule, and see how a unique, self-replicating code can be created.

Building DNA

Construct a DNA molecule, examine its double-helix structure, and then go through the DNA replication process. Learn how each component fits into a DNA molecule, and see how a unique, self-replicating code can be created.

You are the captain of an interplanetary cargo ship, delivering important supplies to the outer planets. The cargo can be stored in barrels, crates, and holds. (There are 10 barrels in a crate, and 10 crates in a hold.) Model multi-digit subtraction by unloading cargo on each planet.

Cargo Captain (Multi-digit Subtraction)

You are the captain of an interplanetary cargo ship, delivering important supplies to the outer planets. The cargo can be stored in barrels, crates, and holds. (There are 10 barrels in a crate, and 10 crates in a hold.) Model multi-digit subtraction by unloading cargo on each planet.

Explore a wide variety of cells, from bacteria to human neurons, using a compound light microscope. Select a sample to study, then focus on the sample using the coarse and fine focus controls of the microscope. Compare the structures found in different cells, then perform tests to see if the sample is alive.

Cell Types

Explore a wide variety of cells, from bacteria to human neurons, using a compound light microscope. Select a sample to study, then focus on the sample using the coarse and fine focus controls of the microscope. Compare the structures found in different cells, then perform tests to see if the sample is alive.

Observe a chemical reaction with and without a catalyst. Determine the effects of concentration, temperature, surface area, and catalysts on reaction rates. Reactant and product concentrations through time are recorded, and the speed of the simulation can be adjusted by the user.

Collision Theory

Observe a chemical reaction with and without a catalyst. Determine the effects of concentration, temperature, surface area, and catalysts on reaction rates. Reactant and product concentrations through time are recorded, and the speed of the simulation can be adjusted by the user.

Mix the primary colors of light by using red, green, and blue lights. Use pieces of colored glass to filter the light and create a wide variety of colors. Determine how light is absorbed and transmitted by each color of glass.

Color Absorption

Mix the primary colors of light by using red, green, and blue lights. Use pieces of colored glass to filter the light and create a wide variety of colors. Determine how light is absorbed and transmitted by each color of glass.

Use dichotomous keys to identify and classify five types of organisms: California albatrosses, Canadian Rockies buttercups, Texas venomous snakes, Virginia evergreens, and Florida cartilagenous fishes. After you have classified every organism, try making your own dichotomous key!

Dichotomous Keys

Use dichotomous keys to identify and classify five types of organisms: California albatrosses, Canadian Rockies buttercups, Texas venomous snakes, Virginia evergreens, and Florida cartilagenous fishes. After you have classified every organism, try making your own dichotomous key!

Observe sound waves emitted from a moving vehicle. Measure the frequency of sound waves in front of and behind the vehicle as it moves, illustrating the Doppler effect. The frequency of sound waves, speed of the source, and the speed of sound can all be manipulated. Motion of the vehicle can be linear, oscillating, or circular.

Doppler Shift

Observe sound waves emitted from a moving vehicle. Measure the frequency of sound waves in front of and behind the vehicle as it moves, illustrating the Doppler effect. The frequency of sound waves, speed of the source, and the speed of sound can all be manipulated. Motion of the vehicle can be linear, oscillating, or circular.

Create the electron configuration of any element by filling electron orbitals. Determine the relationship between electron configuration and atomic radius. Discover trends in atomic radii across periods and down families/groups of the periodic table.

Electron Configuration

Create the electron configuration of any element by filling electron orbitals. Determine the relationship between electron configuration and atomic radius. Discover trends in atomic radii across periods and down families/groups of the periodic table.

Compare the equation of an ellipse to its graph. Vary the terms of the equation of the ellipse and examine how the graph changes in response. Drag the vertices and foci, explore their Pythagorean relationship, and discover the string property.

Ellipses

Compare the equation of an ellipse to its graph. Vary the terms of the equation of the ellipse and examine how the graph changes in response. Drag the vertices and foci, explore their Pythagorean relationship, and discover the string property.

Continue your meteoric rise in the undersea culinary world in this follow-up to Equivalent Algebraic Expressions I. Make equivalent expressions by using the distributive property forwards and backwards, sort expressions by equivalence, and personally assist Chef Grumpy himself with a project that will bring him (and maybe you) fame and fortune.

Equivalent Algebraic Expressions II

Continue your meteoric rise in the undersea culinary world in this follow-up to Equivalent Algebraic Expressions I. Make equivalent expressions by using the distributive property forwards and backwards, sort expressions by equivalence, and personally assist Chef Grumpy himself with a project that will bring him (and maybe you) fame and fortune.

Adjust the number of fish in a lake to be tagged and the number of fish to be recaptured. Use the number of tagged fish in the catch to estimate the number of fish in the lake.

Estimating Population Size

Adjust the number of fish in a lake to be tagged and the number of fish to be recaptured. Use the number of tagged fish in the catch to estimate the number of fish in the lake.

Plant flowers in two gardens to help develop fraction sense. The two gardens act as number lines, from 0 to 1. Use the flowers in the gardens to compare fractions and to explore equivalent fractions. Chalk marks can be drawn to divide the garden into equal sections.

Fraction Garden (Comparing Fractions)

Plant flowers in two gardens to help develop fraction sense. The two gardens act as number lines, from 0 to 1. Use the flowers in the gardens to compare fractions and to explore equivalent fractions. Chalk marks can be drawn to divide the garden into equal sections.

Drop a number into a function machine, and see what number comes out! You can use one of the six pre-set function machines, or program your own function rule into one of the blank machines. Stack up to three function machines together. Input and output can be recorded in a table and on a graph.

Function Machines 2 (Functions, Tables, and Graphs)

Drop a number into a function machine, and see what number comes out! You can use one of the six pre-set function machines, or program your own function rule into one of the blank machines. Stack up to three function machines together. Input and output can be recorded in a table and on a graph.

Use data from up to three weather stations to predict the motion of a hurricane. The wind speed, wind direction, cloud cover and air pressure are provided for each station using standard weather symbols.

Hurricane Motion

Use data from up to three weather stations to predict the motion of a hurricane. The wind speed, wind direction, cloud cover and air pressure are provided for each station using standard weather symbols.

Compare the theoretical and experimental probabilities of drawing colored marbles from a bag. Record results of successive draws to find the experimental probability. Perform the drawings with replacement of the marbles to study independent events, or without replacement to explore dependent events.

Independent and Dependent Events

Compare the theoretical and experimental probabilities of drawing colored marbles from a bag. Record results of successive draws to find the experimental probability. Perform the drawings with replacement of the marbles to study independent events, or without replacement to explore dependent events.

Find the solution set to a linear inequality in two variables using the graph of the linear inequality. Vary the terms of the inequality and vary the inequality symbol. Examine how the boundary line and shaded region change in response.

Linear Inequalities in Two Variables

Find the solution set to a linear inequality in two variables using the graph of the linear inequality. Vary the terms of the inequality and vary the inequality symbol. Examine how the boundary line and shaded region change in response.

Observe the effect of predators on a population of parrots with three possible genotypes. The initial percentages and fitness levels of each genotype can be set. Determine how initial fitness levels affect genotype and allele frequencies through several generations. Compare scenarios in which a dominant allele is deleterious, a recessive allele is deleterious, and the heterozygous individual is fittest.

Microevolution

Observe the effect of predators on a population of parrots with three possible genotypes. The initial percentages and fitness levels of each genotype can be set. Determine how initial fitness levels affect genotype and allele frequencies through several generations. Compare scenarios in which a dominant allele is deleterious, a recessive allele is deleterious, and the heterozygous individual is fittest.

Observe and measure the properties of a mineral sample, and then use a key to identify the mineral. Students can observe the color, luster, shape, density, hardness, streak, and reaction to acid for each mineral. There are 26 mineral samples to identify.

Mineral Identification

Observe and measure the properties of a mineral sample, and then use a key to identify the mineral. Students can observe the color, luster, shape, density, hardness, streak, and reaction to acid for each mineral. There are 26 mineral samples to identify.

Model and compare decimals using area models. Set the number of sections in each model to 1, 10, or 100, and then click in the models to shade sections. Compare decimals visually and on a number line.

Modeling Decimals (Area and Grid Models)

Model and compare decimals using area models. Set the number of sections in each model to 1, 10, or 100, and then click in the models to shade sections. Compare decimals visually and on a number line.

Pith balls with positive, negative, or no electrical charge are suspended from strings. The charge and mass of the pith balls can be adjusted, along with the length of the string, which will cause the pith balls to change position. Distances can be measured as variables are adjusted, and the forces (Coulomb and gravitational) acting on the balls can be displayed.

Pith Ball Lab

Pith balls with positive, negative, or no electrical charge are suspended from strings. The charge and mass of the pith balls can be adjusted, along with the length of the string, which will cause the pith balls to change position. Distances can be measured as variables are adjusted, and the forces (Coulomb and gravitational) acting on the balls can be displayed.

Move the Earth's crust at various locations to observe the effects of the motion of the tectonic plates, including volcanic eruptions. Information about each of the major types of plate boundaries is shown, along with their locations on Earth.

Plate Tectonics

Move the Earth's crust at various locations to observe the effects of the motion of the tectonic plates, including volcanic eruptions. Information about each of the major types of plate boundaries is shown, along with their locations on Earth.

Compare sample distributions drawn from population distributions. Predict characteristics of a population distribution based on a sample distribution and examine how well a small sample represents a given population.

Populations and Samples

Compare sample distributions drawn from population distributions. Predict characteristics of a population distribution based on a sample distribution and examine how well a small sample represents a given population.

Exothermic chemical reactions release energy, while endothermic reactions absorb energy. But what causes some reactions to be exothermic, and others to be endothermic? In this simulation, compare the energy absorbed in breaking bonds to the energy released in forming bonds to determine if a reaction will be exothermic or endothermic.

Reaction Energy

Exothermic chemical reactions release energy, while endothermic reactions absorb energy. But what causes some reactions to be exothermic, and others to be endothermic? In this simulation, compare the energy absorbed in breaking bonds to the energy released in forming bonds to determine if a reaction will be exothermic or endothermic.

Understand how topographic maps work by creating a three-dimensional landscape and observing the corresponding contour lines. See how mountains, depressions, valleys and cliffs are represented on topographic maps. Fill in the landscape with water to demonstrate that contours are lines of constant elevation.

Reading Topographic Maps

Understand how topographic maps work by creating a three-dimensional landscape and observing the corresponding contour lines. See how mountains, depressions, valleys and cliffs are represented on topographic maps. Fill in the landscape with water to demonstrate that contours are lines of constant elevation.

Measure the time required to write a word when the mouse behaves in a normal fashion and when the direction of motion is reversed from left to right, up to down, or both. Run several experiments in each mode to see if your brain and muscles are able to adapt to the new direction of motion. Determine which type of inversion is easiest to adjust to and whether you can train yourself to function normally when the inversion is present.

Reverse the Field

Measure the time required to write a word when the mouse behaves in a normal fashion and when the direction of motion is reversed from left to right, up to down, or both. Run several experiments in each mode to see if your brain and muscles are able to adapt to the new direction of motion. Determine which type of inversion is easiest to adjust to and whether you can train yourself to function normally when the inversion is present.

Explore acceleration, speed, momentum, and energy by sending a sled down a hill into a group of snowmen. The starting height and mass of the sled can be changed, as well as the number of snowmen. In the Two sleds scenario, observe collisions between sleds of different masses and starting heights.

Sled Wars

Explore acceleration, speed, momentum, and energy by sending a sled down a hill into a group of snowmen. The starting height and mass of the sled can be changed, as well as the number of snowmen. In the Two sleds scenario, observe collisions between sleds of different masses and starting heights.

Observe the tilt of Earth's axis and the angle that sunlight strikes Earth on June 21 and December 21. Compare day lengths, temperatures, and the angle of the Sun's rays for any latitude. The tilt of the Earth's axis can be varied to see how this would affect seasons.

Summer and Winter

Observe the tilt of Earth's axis and the angle that sunlight strikes Earth on June 21 and December 21. Compare day lengths, temperatures, and the angle of the Sun's rays for any latitude. The tilt of the Earth's axis can be varied to see how this would affect seasons.

Vary the dimensions of a prism or cylinder and investigate how the surface area changes. Use the dynamic net of the solid to compute the lateral area and the surface area of the solid.

Surface and Lateral Areas of Prisms and Cylinders

Vary the dimensions of a prism or cylinder and investigate how the surface area changes. Use the dynamic net of the solid to compute the lateral area and the surface area of the solid.

Vary the coefficients in the equation of a function and examine how the graph of the function is translated or scaled. Select different functions to translate and scale, and determine what they have in common.

Translating and Scaling Functions

Vary the coefficients in the equation of a function and examine how the graph of the function is translated or scaled. Select different functions to translate and scale, and determine what they have in common.

Examine the scatter plot for a random data set with negative or positive correlation. Vary the correlation and explore how correlation is reflected in the scatter plot and the trend line.

Trends in Scatter Plots

Examine the scatter plot for a random data set with negative or positive correlation. Vary the correlation and explore how correlation is reflected in the scatter plot and the trend line.