| Radioactive Equilibrium (exp#: 71990-923) |
| Ratio of Charge to Mass for the Electron (exp#: 71990-711) |
| Reactance, Impedance, Electric Resonance (exp#: 71990-682) |
| Reflection and Refraction (exp#: 71990-531) |
| Reflection of Light - Ray Tracing (exp#: 71990-528) |
| Refraction of Light - Ray Tracing (exp#: 71990-529) |
| Refraction at a Single Spherical Surface (exp#: 71990-533) |
| Refraction of Light at a Plane Surface (Index of Refraction: Plate and Prism) (exp#: 71990-518) |
| Refraction of Light by Liquids (Refraction Tank) (exp#: 71990-535) |
| Refraction Through a Single Thin Lens (exp#: 71990-522) |
| Relative Humidity (exp#: 71990-391) |
| Resistance and Power by the Voltmeter - Ammeter Method (exp#: 71990-703) |
| Resistors in Series and in Parallel (exp#: 71990-655) |
| Resonance in Air Columns (exp#: 71990-830) |
| Resonance in Open and Closed Pipes (exp#: 71990-822) |
| Rotational Inertia: Angular Motion (exp#: 71990-162) |
| Rotational Inertia; Angular Motion (Electronic Timer) (exp#: 71990-165) |