Shine white light or a single-color beam through a prism. Explore how a prism refracts light and investigate the factors that affect the amount of refraction. The index of refraction of the prism, width of the prism, prism angle, light angle, and light wavelength can be adjusted.

Basic Prism

Explore the processes of photosynthesis and respiration that occur within plant cells. The cyclical nature of the two processes can be constructed visually, and the photosynthesis and respiration equations can be balanced in a descriptive and numerical format.

Cell Energy Cycle

Chemical changes result in the formation of new substances. But how can you tell if a chemical change has occurred? Explore this question by observing and measuring a variety of chemical reactions. Along the way you will learn about chemical equations, acids and bases, exothermic and endothermic reactions, and conservation of matter.

Chemical Changes

Trace the path of blood through a beating heart and the network of blood vessels that supplies blood to the body. Take blood samples from different blood vessels to observe blood cells and measure the levels of oxygen, carbon dioxide, sugar, and urea.

Circulatory System

Explore the relationship between the correlation coefficient of a data set and its graph. Fit a line to the data and compare the least-squares fit line.

Correlation

Build a glucose molecule, atom-by-atom, to learn about chemical bonds and the structure of glucose. Explore the processes of dehydration synthesis and hydrolysis in carbohydrate molecules.

Dehydration Synthesis

Drop a chunk of material in a beaker of water and observe whether it sinks or floats. Cut the chunk into smaller pieces of any size, and observe what happens as they are dropped in the beaker. The mass and volume of each chunk can be measured to gain a clear understanding of density and buoyancy.

Density Experiment: Slice and Dice

Calculate the difference between the times given by two analog clocks. Rotate the hands of the clocks to change the time and see how the calculation changes.

Elapsed Time

Investigate the motion of an object as it falls to the ground. A variety of objects can be compared, and their motion can be observed in a vacuum, in normal air, and in denser air. The position, velocity, and acceleration are measured over time, and the forces on the object can be displayed. Using the manual settings, the mass, radius, height, and initial velocity of the object can be adjusted, as can the air density and wind.

Free-Fall Laboratory

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 3 (Functions and Problem Solving)

Compare the equation of a rational function to its graph. Multiply or divide the numerator and denominator by linear factors and explore how the graph changes in response.

General Form of a Rational Function

Test your hearing range by listening to low-, medium-, and high-frequency sounds. Compare the relative loudness of sounds at each frequency to create an equal-loudness curve. In a quiet room, measure your threshold of audibility for each frequency, and compare your results to others. The volume of each sound can be adjusted.

Hearing: Frequency and Volume

Control a simulated person running on a treadmill. Your challenge is to use clothing, exercise, and sweat to maintain a constant body temperature as air temperature goes up and down. Sweating (perspiration) can be controlled automatically by the Gizmo or, for a challenge, manually by the user. Don't forget to eat and drink!

Homeostasis

Sort and pair the images of human chromosomes obtained in a scan. Find differences in the scans of the various patients to find out specific things that can cause disease, as well as the gender of the person.

Human Karyotyping

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

Determine if a relation is a function using the mapping diagram, ordered pairs, or the graph of the relation. Drag arrows from the domain to the range, type in ordered pairs, or drag points to the graph to add inputs and outputs to the relation.

Introduction to Functions

Fit a line to the data in a scatter plot using your own judgment. Then compare the least squares line of best fit.

Least-Squares Best Fit Lines

Drag bar magnets and a variety of other objects onto a piece of paper. Click Play to release the objects to see if they are attracted together, repelled apart, or unaffected. You can also sprinkle iron filings over the magnets and other objects to view the magnetic field lines that are produced.

Magnetism

Factor a polynomial with a leading coefficient equal to 1 using an area model. Use step-by-step feedback to diagnose any mistakes.

Modeling the Factorization of *x*^{2}+*bx*+*c*

Multiply two fractions using an area model. Vary the vertical area to change one fraction and vary the horizontal area to change the other. Then examine the intersection of the areas to find the product.

Multiplying Fractions

The alien school children from the planet Zigmo travel to distant planets on a field trip. The goal is to select a bus size so that all buses are full and no aliens are left behind. This is a nice illustration of division with remainders.

No Alien Left Behind (Division with Remainders)

Observe the five main types of nuclear decay: alpha decay, beta decay, gamma decay, positron emission, and electron capture. Write nuclear equations by determining the mass numbers and atomic numbers of daughter products and emitted particles.

Nuclear Decay

How do scientists measure and describe the weather? In this introductory lesson, students will practice using a thermometer, anemometer, rain gauge, and hygrometer to record weather conditions in a variety of locations and dates. This lesson uses U.S. customary units.

Observing Weather (Customary)

Derive the sum of the angles of a polygon by dividing the polygon into triangles and summing their angles. Vary the number of sides and determine how the sum of the angles changes. Dilate the polygon to see that the sum is unchanged.

Polygon Angle Sum

Observe the populations of grass, prairie dogs, ferrets and foxes in a prairie ecosystem. Investigate feeding relationships and determine the food chain. Bar graphs and line graphs show changes in populations over time.

Prairie Ecosystem

Experiment with spinners and compare the experimental probability of particular outcomes to the theoretical probability. Select the number of spinners, the number of sections on a spinner, and a favorable outcome of a spin. Then tally the number of favorable outcomes.

Probability Simulations

Lift a variety of heavy objects (armchair, safe, piano) using pulleys and a rope. Systems of one, two, four, or six pulleys can be used. Up to six people can be used to pull on the rope, which adds force (effort).

Pulleys

Compare the graph of a quadratic to its equation in polynomial form. Vary the coefficients of the equation and explore how the graph changes in response.

Quadratics in Polynomial Form

Test your reaction time by catching a falling ruler or clicking a target. Create a data set of experiment results, and calculate the range, mode, median, and mean of your data. Data can be displayed on a list, table, bar graph or dot plot. The Reaction Time 1 Student Exploration focuses on range, mode, and median.

Reaction Time 1 (Graphs and Statistics)

Explore how river erosion affects landscapes in the short term and over long periods of time. Describe the features of mountain streams and meandering rivers, and use a floating barrel to estimate current speed. Witness the changes that occur as mountain streams erode downward and meandering rivers erode from side to side.

River Erosion

Plan a cross-country road trip through various U.S. state capitals. First choose a vehicle to drive, and then fill up the tank with gas and go! Find the range and gas mileage of each vehicle, and discover the shortest path between two cities.

Road Trip (Problem Solving)

Gain an understanding of the causes of seasons by observing Earth as it orbits the Sun in three dimensions. Observe the path of the Sun across the sky on any date and from any location. Create graphs of solar intensity and day length, and use collected data to describe and explain seasonal changes.

Seasons in 3D

Meet Spidro, a quirky critter with an appetite for algebraic expressions! As Spidro's adopted owner, it's your responsibility to feed him so that he grows into… whatever it is that a Spidro grows into. But be careful - Spidro is a picky eater who prefers his food to be as simple as possible. Use the commutative property, distributive property, and the other properties of addition and multiplication to put expressions in simplest (and tastiest) form.

Simplifying Algebraic Expressions I

Solve systems of linear equations, written in standard form. Explore what it means to solve systems algebraically (with substitution or elimination) and graphically. Also, use a draggable green point to see what it means when (*x*, *y*) values are solutions of an equation, or of a system of equations.

Solving Linear Systems (Standard Form)

Compare the graph of the tangent function with the graph of the angle on the unit circle. Drag a point along the tangent curve and see the corresponding angle on the unit circle.

Tangent Function

Create a set of stuffed animals: monkeys, giraffes, and rabbits. Toys can be painted red, green, or blue. Describe the makeup of the set (animals or colors) with fractions. Arrange the toys into groups to simplify the fractions.

Toy Factory (Set Models of Fractions)

Arrange blocks in a three-dimensional space so that the top view, front view, and side view match the target top view, front view, and side view.

3D and Orthographic Views

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

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

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 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

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)

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

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

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

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

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

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

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

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

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

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)

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)

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

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

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

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 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

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)

Observe frogs jumping around on colored lily pads. Find, test, and reason about patterns you see in their jumping.

Pattern Finder

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

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

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

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

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

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

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 the slope of a line, and learn how to calculate slope. Adjust the line by moving points that are on the line, and see how its slope changes.

Slope

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

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 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

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

Adjust the values in a quadratic function, in vertex form or in polynomial form, to "zap" as many data points as possible.

Zap It! Game