Where the physics comes from
Sources
The physics here is ordinary, checked against public references. Each phenomenon also lists its sources at the bottom of its page.
The Floor Pushes Back
- NASA: Newton’s Laws of Motion · A clear statement of the three laws, including action and reaction.
- The Physics Classroom: Normal Force · What “normal” means, and how the floor’s push is not the same thing as weight.
The Invisible Push
- NIST: Magnetic fields · What a magnetic field is, and how it is measured.
- NASA: Earth’s magnetosphere · Earth itself is a magnet. The same kind of field, scaled up.
The Nail and the Ship
- Britannica: Archimedes’ principle · The buoyant force equals the weight of the displaced fluid.
- NASA Glenn: Buoyant force · An object floats when the weight of displaced fluid matches the object’s weight.
Lightning First
- NOAA: Determining distance to a thunderstorm · About a mile every five seconds, a kilometer every three. Temperature changes the exact speed.
- National Weather Service: Thunder · Thunder is the sound of the flash. Count, then go inside if it is close.
- Encyclopaedia Britannica: Speed of sound · The speed of sound in air depends on temperature. 343 m/s is a typical 20 °C figure.
Keep Falling
- NASA: What is orbit? · Orbit as falling and missing, in language meant for children.
- NASA: International Space Station facts · Height and speed of a real orbit, not a drawing.
Paper Bridge
- Exploratorium: Science Snacks · Hands-on structure activities with ordinary materials.
- National Academies: Teaching about structure · How load, shape, and material share the work in real structures.
The Dark Shape
- NASA: Why is the sky blue, and how light travels · Sunlight as something that travels, and can be blocked.
- Exploratorium: Shadows · Hands-on light and shadow with ordinary lamps.
The Road Holds the Car
- The Physics Classroom: Pressure · Force, area, and the floor’s push, told without a trick.
- NASA Glenn: Pressure · Pressure as force over area.
The Warm Phone
- NASA: Conservation of Energy · Energy changes form. It is not used up.
- The Physics Classroom: Thermal Energy · Heat as energy on the move, not a substance.
The Thrown Stone
- NASA: Newton’s Laws of Motion · Action and reaction, including why throwing mass backward is a push.
- NASA Glenn: Rocket principles · Thrust without needing air to paddle against.