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Liquid nitrogen is pumped on and freezes into a sponge of solid nitrogen.

The liquid nitrogen is in a 600 or 800 ml beaker under a shielded bell jar on top of the red vacuum cart. A cold trap is not necessary if only nitrogen is being pumped on.

It is...

A vacuum is drawn over a beaker of sliced cucumber covered in a clear dressing. The cucumber outgases, making bubbles. When the atmosphere is readmitted, the dressing is forced into the cucumber, rendering it translucent and seasoned. 

A polycarbonate bell...

Dark red iron[III] solution is rapidly reduced to colorless iron[II] by addition of tin[II] chloride solution, with the rate depending on concentration and temperature.

Four medium footed cylinders are prepared with 100 ml of ferric chloride solution 0.01M...

A magnesium ribbon is held with tongs and lit with a match or torch, making a bright flame that consumes the ribbon from the bottom up.

The ribbon should be about 20-30 cm long. Hold the ribbon with the tongs high and at arms length. Let the magnesium...

A vintage collection of 16 wooden models of the s, p, d, and f atomic orbitals.

30% Hydrogen peroxide in a large round bottom flask decomposes rapidly to hissing steam and oxygen when potassium iodide is added.

[https://harvard.hosted.panopto.com/Panopto/Pages/Viewer.aspx?id=c3f365a…; video of...

Two clean plastic cups, one filled with room temperature water, the other empty, for a student to test with their finger.

Supported by experience, this is a way to introduce heat capacity as an important variable in measuring temperature.

Make sure the...

Vinegar and two different amounts of baking soda in plastic soda bottles with balloons.

Video of the demo in action https://youtu.be/GQbULuidNKg

Two 500ml PETN soda bottles of the same make, split a bottle of vinegar between them.

11" balloons are pre...

Curls of zinc and magnesium are dropped into 2M hydrochloric acid, and bubbles observer'd.

Video of our demo in action https://youtu.be/6L6t8O4J_Eo

A 600ml beaker, clean and clear, is at the focal point of a camera projecting the image of 500 ml of 2M...

Potassium iodide solution is added to lead nitrate solution, and bright yellow lead iodide precipitates.

Potassium iodide solution is 0.1 M and lead nitrate solution is 0.01M.

The lead nitrate solution is about 350 ml in a 600ml beaker, and the KI sol'n is...