Surveyor's Measuring Reel

Details

9AA300 - Measurement Tools

Demo use only

Instances

Stanley
G2B20A - Demo West (Duane Physics)
Good - Normal Wear Demo use only

Used in these demonstrations

Lecture hall triple chalkboards with ABCD reference card on far left and individual colored letter cards (A, B, C, D) magneted at intervals across the boards

Blind Spot

Students locate their visual blind spot--the region where the optic nerve exits the retina with no photoreceptors. Demonstrates that the brain actively fills in missing visual information rather than passively …
Clear graduated bucket with two dark bowling balls in water: the lighter ball floats at the surface (partially submerged) and the heavier ball sits on the bottom

Density of Bowling Balls

Two bowling balls of the same size but different masses are weighed, their densities calculated, and then placed in water. The heavy ball (6.6 kg) sinks; the light ball (3.1 …
Close-up of a dark globe with white grid lines. Two small red-and-black magnets stand on a meridian, separated by a white measuring tape. The upper magnet casts a visible shadow.

Measuring the Earth

Recreates Eratosthenes' method for measuring Earth's circumference using a globe, a light source, and two magnets. Students use shadow lengths and proportional reasoning to calculate the globe's circumference, then verify …
Close-up of scale planet models on a clear acrylic surface: a small white marble on a hex nut, two peppercorns, a large decorative marble on a metal ring, and tiny dots barely visible on the surface

Scale Inner Solar System

Creates a 1:10 billion scale model of the solar system using everyday objects, matching the Colorado Scale Model Solar System. Students pace out planetary distances in the lecture hall to …

The Moon Illusion

Explores oculomotor micropsia/macropsia as one mechanism behind the Moon Illusion. Students discover that perceived size depends on eye focus distance, not just angular diameter, by matching disk sizes at different …

Reserve This Equipment

Demo use only

This equipment supports lecture demonstrations and cannot be reserved directly — it is assigned automatically as part of a demonstration. To use it, request a demo that includes it.