# All

Title Summary Post date

## Pitot Tubes

Keywords: air speed, Bernoulli's equation, fluid speed, fluids, Pitot tubes

How can wasps endanger a commercial airline flight?

This article explains how a Pitot tube is used to measure speed of a fluid and is applied to measure the air speed of aircraft. Bernoulli's equation forms the basic principle of fluid speed measurements using Pitot tubes.

4 years 3 weeks ago

## Histograms, Measurement, and Uncertainty

4 years 45 weeks ago

Keywords: Generate Sine Wave, Light Sensing Instrument, Light Theremin

Is it possible to create a musical instrument that can be played without direct contact?

A more complicated version of the simple Light Theremin. This version uses another light sensor for volume control, and sounds much closer to the original Capacitive Theremin.

4 years 46 weeks ago

## Light Theremin (Simple)

Keywords: Hands-Free, Light Theremin, Lights Sensing Instrument

Is it possible to create a musical instrument that can be played without direct contact?

This project takes the student through the steps to build a simple Light Theremin, an instrument which changes its pitch depending on how much light is shone upon it.

4 years 46 weeks ago

## C21 Video Contest Top Videos

5 years 19 weeks ago

## Stretching Rubber Bands

Keywords: Elasticity, Hooke's Law, Rubber bands, Young's Modulus

Why is this energy bar hanging from a rubber band?

In this project you will explore the elastic properties of rubber bands.

5 years 19 weeks ago

## MRI Machines and You

Keywords:

An explanation of how MRI machines take advantage of nuclear spins to image precise slices of a person.

5 years 23 weeks ago

## Oscillations and Waves

Keywords: Circular Motion, interference, Oscillations, Rotational Motion, Standing Waves, Superposition, waves

What do waves, oscillations, and rotations have in common?

Surprisingly, rotations, oscillations, and waves can be described with similar math. In this article, we make the math come alive by using Excel or Calc programs to simulate oscillations and wave effects. You can learn how to do this yourself by following our videos.

5 years 25 weeks ago

## Laminar (Un)mixing

Keywords: activity, fluids, laminar flow, mixing, reynolds number

"Unmixing" a mixture is impossible, right? So what's going on here?

Find out how to construct your own "(un)mixing" demonstration and learn about how it works here.

5 years 30 weeks ago

## How big was the aerodynamic force on Felix Baumgartner at 1342 km/h? (Or on Alan Eustace at 1321 km/h?)

Keywords: aerodynamics, drag, felix baumgartner, free fall

Did you watch Felix Baumgartner jump out of a balloon gondola at an altitude of 39 km? Here's a question for your physics students, or even your physics teacher! How big was the drag force on Felix Baumgartner at his maximum speed of 1342 km/h? Pretty enormous, right? Wrong.

Knowing next to nothing about how aerodynamic drag varies as one hits the sound barrier, there is very simple way to assess the aerodynamic drag on a falling object at its maximum speed. Even at 1432 km/h. In fact the maximum aerodynamic drag occurs afterwards when the falling object is slowing down in the denser lower atmosphere. To asses how big the force was on Felix Baumgartner, we create a simple mathematical model of his fall.