# PhET Simulations

Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education research and engage students through an intuitive, game-like environment where students learn through exploration and discovery.

• PhET: Acid-Base Solutions
How do strong and weak acids differ? Use lab tools on your computer to find out! Dip the paper or the probe into solution to measure the pH, or put in the electrodes to measure the conductivity. Then see how concentration and strength affect pH. Can a weak acid solution have the same pH as a strong acid solution?
• PhET: Balancing Chemical Equations
How do you know if a chemical equation is balanced? What can you change to balance an equation? Play a game to test your ideas!
• PhET: Beer's Law Lab
“The thicker the glass, the darker the brew, the less the light that passes through.” Make colorful concentrated and dilute solutions and explore how much light they absorb and transmit using a virtual spectrophotometer!
• PhET: Build an Atom
Build an atom out of protons, neutrons, and electrons, and see how the element, charge, and mass change. Then play a game to test your ideas!
• PhET: Color Vision
Make a whole rainbow by mixing red, green, and blue light. Change the wavelength of a monochromatic beam or filter white light. View the light as a solid beam, or see the individual photons.
• PhET: Concentration
Watch your solution change color as you mix chemicals with water. Then check molarity with the concentration meter. What are all the ways you can change the concentration of your solution? Switch solutes to compare different chemicals and find out how concentrated you can go before you hit saturation!
• PhET: Gene Expression Essentials
Express yourself through your genes! See if you can generate and collect three types of protein, then move on to explore the factors that affect protein synthesis in a cell.
• PhET: Molarity
What determines the concentration of a solution? Learn about the relationships between moles, liters, and molarity by adjusting the amount of solute and solution volume. Change solutes to compare different chemical compounds in water.
• PhET: Molecules and Light
Adjust light source slider and begin your observations of how different molecules react to different light sources. Note that the interactive elements in this sim have simple description that can be accessed using a screen reader.
• PhET: Molecule Polarity
When is a molecule polar? Change the electronegativity of atoms in a molecule to see how it affects polarity. See how the molecule behaves in an electric field. Change the bond angle to see how shape affects polarity.
• PhET: Molecule Shapes
Explore molecule shapes by building molecules in 3D! How does molecule shape change with different numbers of bonds and electron pairs? Find out by adding single, double or triple bonds and lone pairs to the central atom. Then, compare the model to real molecules!
• PhET: Molecule Shapes: Basics
Explore molecule shapes by building molecules in 3D! Find out how a molecule's shape changes as you add atoms to a molecule.
• PhET: Neuron
Stimulate a neuron and monitor what happens. Pause, rewind, and move forward in time in order to observe the ions as they move across the neuron membrane.
• PhET: pH Scale
Test the pH of things like coffee, spit, and soap to determine whether each is acidic, basic, or neutral. Visualize the relative number of hydroxide ions and hydronium ions in solution. Switch between logarithmic and linear scales. Investigate whether changing the volume or diluting with water affects the pH. Or you can design your own liquid!
• PhET: pH Scale: Basics
Test the pH of everyday liquids such as coffee, spit, and soap to determine whether each is acidic, basic, or neutral. Investigate how adding more of a liquid or diluting with water affects pH.
• PhET: Reactants, Products and Leftovers
Explore what makes a reaction happen by colliding atoms and molecules. Design experiments with different reactions, concentrations, and temperatures. When are reactions reversible? What affects the rate of a reaction?