Explore lessons
Filter by age or subject. Faded cards are on the way.
Counting to 10
Tap to add, count each one once, and see groups of five and ten.
Comparing numbers
Match up two groups to see which has more, then use >, < and = with numbers up to 99.
Shapes around us
Count sides and corners, turn and stretch shapes, then find every triangle in the picture.
Add and take away
Apples come and go from a basket. Count how many there are now and write it as a number sentence.
Push and pull
Push or pull a ball, a toy car and a heavy box. See how hard and which way changes where they go.
Tens and ones
Build numbers with blocks, bundle ten ones into a ten, and see what each digit means.
Even and odd numbers
Pair up blocks two by two: even numbers match up perfectly, odd numbers leave one behind.
Telling time
Drag the hands of a clock. Read hours, half hours and five-minute times in numbers and words.
Sink or float?
Drop things into the water and discover what makes them float.
Light and shadows
Shine a flashlight through glass, paper, a teddy bear and a mirror. Which ones make a shadow?
Sounds are vibrations
Tap a drum with rice on it and pluck thin and thick strings. Loud, quiet, high and low sounds all come from vibrations.
Solids, liquids and gases
Heat and cool a box of water particles and watch them shake as ice, slide as water and fly apart as steam.
Multiplication as arrays
Arrange cookies in rows and columns, skip-count the rows, and turn the array to see 3 × 4 = 4 × 3.
Division as sharing
Deal cookies onto plates or pack them into bags, find the leftovers, and see how division undoes multiplication.
What is a fraction?
Split a whole into equal parts and see the same fraction as a bar, a circle and a point on a number line.
Equivalent fractions
Slice a fraction bar into smaller pieces and watch the numbers change while the amount stays the same.
Area and perimeter
Stretch a rectangle on a grid: count the squares inside, walk around the edge, and solve shape puzzles.
Balanced and unbalanced forces
Play tug of war: equal pulls cancel out, and a bigger pull makes things move.
Magnets
Slide two magnets together: opposite poles attract, the same poles repel. Then test which things stick to a magnet.
Light and color
Mix red, green and blue spotlights, then light an apple with different lamps to see why objects have colors.
Levers and simple machines
Slide the pivot of a lever and lift a heavy rock with a small push. Weight × distance tells who wins.
Factors and prime numbers
Arrange tiles into rectangles: factors are the sides you can make, and primes can only make one long row.
Measuring angles
Turn a ray, measure it with a protractor, name the angle, and see that angles add up.
Decimals
Shade a hundred grid to build tenths and hundredths, read them as fractions and words, and compare tricky pairs like 0.5 and 0.45.
Forms of energy
Follow energy through a flashlight, a solar fan, a crank radio, a toaster and a wind turbine as it moves and changes form.
Simple circuits
Connect batteries and bulbs, test what conducts electricity, and compare series with parallel.
Volume
Build boxes from unit cubes, split them into layers, and discover why volume is length × width × height.
Gravity pulls down
Drop balls all around the Earth to see that “down” points to its center, then race a bowling ball and a feather on Earth, the Moon, Mars and Jupiter.
Ratios
Mix blue and yellow paint. Equivalent ratios make the same green, and a ratio table shows why.
Percentages
Shade a hundred grid, line up percents with amounts, and work out real discounts.
Mean, median and mode
Build a dot plot, find the tallest stack, the middle value and the balance point, and see which one an outlier pulls.
Negative numbers
Temperatures below zero, depths below sea level and money owed: order them, find opposites and distance from zero.
Speed and motion graphs
Set a walker’s speed for three parts of a trip and watch the distance–time graph appear. Steeper means faster; flat means stopped.
Heat and temperature
Touch a hot block to a cold one and watch heat flow from fast-jiggling particles to slow ones until both are the same.
Density: why things float
Build blocks of cork, wood, ice, brick and iron, divide mass by volume, and see why less dense things float.
Waves
Shake a rope and a spring. Change amplitude and frequency, measure the wavelength, and see that waves carry energy, not stuff.
Probability
Flip coins, roll dice and spin a spinner hundreds of times, and watch the results settle toward the probability.
Circles and π
Roll a wheel to unroll its circumference, discover π, then slice a circle into a near-rectangle to find its area.
Equations as a balance
Solve equations on a balance scale: whatever you do to one side, do to the other.
Pressure
Stand a brick on each face and watch the same weight dig deeper when it presses on a smaller area.
Slope
Drag two points and measure how steep the line is: rise over run, and y = mx + b.
The Pythagorean theorem
Drag a right triangle, watch the squares on its sides, and see a proof that needs no algebra.
Moving shapes: transformations
Slide, flip, turn and resize a triangle on a grid, and find the coordinate rule behind each move.
Systems of equations
Drag a point until it sits on two lines at once and discover that the crossing solves both equations.
Functions and graphs
Feed numbers into a function machine and watch the table and graph grow: linear, quadratic and exponential.
Patterns and sequences
Build arithmetic and geometric sequences as bars, find the rule for any term, and see doubling overtake adding.
Quadratic functions
Drag a parabola’s vertex and roots. Watch the same curve in vertex, standard and factored form.
Exponential growth
Race adding against multiplying. See when exponential growth pulls ahead, how fast things double, and how decay halves.
Sine, cosine and tangent
Grow and shrink a right triangle and watch its side ratios stay fixed: they depend only on the angle.
Motion in a straight line
Drive a car with a starting velocity and constant acceleration. Position, velocity and acceleration graphs move together, and the area under v–t is the distance.
Newton's laws
Push a cart, add friction, change the mass, and see F = ma on a live velocity graph.
Friction and ramps
Tilt a ramp until a block starts to slide, split gravity into parts, and compare ice, wood and rubber.
Projectile motion
Launch a ball, trace its parabola, and split the motion into two simple parts.
The Doppler effect
Race a siren across the screen and see its sound waves bunch up ahead and stretch out behind, then hear the pitch drop.
Logarithms
Slide along a log ruler where every step multiplies, and see why logarithms turn multiplying into adding.
The unit circle and sine waves
Spin a point around a circle and watch its height draw the sine wave.
Vectors
Drag two arrows on a grid. Add them tip to tail, subtract and scale them, and read off components, length and direction.
The normal distribution
Drop balls through a bean machine and watch a bell curve appear. Then use μ, σ and z-scores to find what share of values lies below a point.
Momentum and collisions
Crash two carts on a track. Bouncy or sticky, the total momentum before equals the total after.
Conservation of energy
Send a skater down a ramp and watch energy change between motion, height and heat, while the total never changes.
Refraction and lenses
Shine a laser into water and glass, watch it bend by Snell’s law or reflect completely, then move a candle to see the image a lens makes.
Ohm's law and circuits
Turn up the voltage, change the resistance, add resistors in series or parallel, and watch the current follow I = V / R.
The derivative: slope of a curve
Slide a point along a curve and shrink a secant until it becomes the tangent. Its slope is the derivative.
Integrals as area
Fill the area under a curve with thinner and thinner rectangles and watch the sum close in on the integral.
Orbits and gravity
Fire Newton’s cannon faster and faster until the ball falls all the way around the Earth, and see why gravity weakens with distance.
Circular motion
Swing a ball on a string, watch velocity and acceleration arrows, and cut the string to see where it goes.
Springs and pendulums
Set a spring or pendulum swinging, watch it draw a sine wave, and find what sets its rhythm.
Wave interference
Make ripples from two sources and find where the waves add up and where they cancel, using the path difference.
Electric charges and fields
Drag positive and negative charges, watch them push and pull by Coulomb’s law, and map the electric field around them.
Electromagnetism
Switch on a current and watch compass needles swing around the wire, then push a magnet through a coil to make electricity.
Nothing here yet. Try another filter.