Physics
Ages 6–8 · Grades 1–2
- Push, Pull and What Makes Things MoveA force is a push or a pull.
- Why Some Things FloatFloating is not decided by how heavy something is.
- Light and ShadowsLight travels in straight lines until something blocks it.
- Sunlight Warms ThingsSunlight warms whatever it shines on.
- Why You Cannot See in the DarkWe can only see things when there is light.
- Sounds Come From ShakingSounds are made by things that vibrate, or shake back and forth very fast.
- See-Through, Cloudy or BlockedTransparent materials let light through, translucent ones let some through, and opaque ones block it.
- Faster Down a Steeper HillA bigger push makes things go faster and farther.
- Rough and Smooth: Why Things Slow DownRubbing between surfaces, called friction, slows moving things down.
- Sending Messages With Light and SoundLight and sound can carry messages over a distance.
Ages 8–11 · Grades 3–5
- Why Moving Things Keep MovingA moving object keeps moving unless a force acts on it.
- Why Everything Falls the Same WayObjects of different mass fall at the same rate.
- Pushing Without TouchingMagnets have two ends, and like ends repel while unlike ends attract.
- How Sound Gets to Your EarSound is made by something vibrating.
- Making a Bulb Light UpElectricity flows only around a complete loop, called a circuit.
- Balloons That Stick to the WallRubbing moves tiny charges between materials, leaving one negative and the other positive.
- Swings Keep TimeA pendulum repeats its motion, so it can be used to keep time.
- Faster Means More EnergyA moving object carries energy, and it carries more when it moves faster.
- Changing Energy From One Kind to AnotherMachines change energy from one form into another; none of them makes energy.
- Messages Made of PatternsA signal carries information when its pattern stands for something agreed.
Ages 11–14 · Grades 6–8
- Where the Energy GoesEnergy changes form rather than being created or destroyed.
- Spreading a Force OutPressure is force divided by the area it acts over.
- How Heat MovesHeat moves by conduction, convection and radiation.
- Adding Up the ForcesAn object’s motion changes only when the forces on it are unbalanced; the total is called the net force.
- Waves Carry Energy, Not WaterA wave carries energy from place to place without carrying the material along.
- Every Push Pushes BackForces always come in pairs that are equal in size and opposite in direction.
- Magnets You Can Switch OffAn electric current makes a magnetic field around a wire.
- Speed Counts TwiceKinetic energy depends on mass and on speed multiplied by itself.
- Light Bounces, Bends and Is Soaked UpLight reflects, refracts, is absorbed or passes through, often several at once.
- Mass Stays, Weight ChangesMass is the amount of matter, in kilograms; weight is a force, in newtons.
Ages 14–18 · Grades 9–12
- Two Motions at OnceHorizontal and vertical motion are independent of each other.
- What Survives a CollisionMomentum is mass times velocity, and it is conserved in every collision.
- What Actually Flows in a WireCurrent is a flow of charge and needs a complete loop.
- Trading Height for SpeedGravitational potential energy mgh converts to kinetic energy ½mv², so v = √(2gh) when nothing else takes a share.
- Falling Around the EarthAn orbit is a fall in which the ground curves away as fast as the object drops.
- Force, Mass and AccelerationAcceleration is proportional to the net force and inversely proportional to mass.
- The Force Between ChargesThe electric force between charges follows an inverse-square law, like gravity.
- Making Electricity With a Moving MagnetA changing magnetic field through a coil induces a voltage across it.
- Why Heat Only Flows One WayHeat flows from hotter to colder until everything reaches the same temperature.
- Light You Cannot SeeVisible light is a narrow band of a much wider electromagnetic spectrum.