Uploaded December 2016 | Updated September 2026, 2 weeks ago
In this video I will show you how to build a Schlieren setup using a laser pointer. There were quite a few questions on my first How To video, so I figured I would post a guide here.
I use a little red laser pointer as my light source. To get the beam to diverge, I bought a plano-convex lens from Thorlabs (part number LA1213). Everything else in the setup is the same as the other setup.
===== RELEVANT LINKS =====
→ Original DIY Schlieren Video
goo.gl/dGSn23
→ Thorlabs Plano-Convex Lens
goo.gl/IfZu8d
In this video I will show you how to build a Schlieren setup using a laser pointer. There were quite a few questions on my first How To video, so I figured I would post a guide here.
I use a little red laser pointer as my light source. To get the beam to diverge, I bought a plano-convex lens from Thorlabs (part number LA1213). Everything else in the setup is the same as the other setup.
===== RELEVANT LINKS =====
→ Original DIY Schlieren Video
goo.gl/dGSn23
→ Thorlabs Plano-Convex Lens
goo.gl/IfZu8d
![Explained: TI-83 Linear Interpolation Program [Math]](https://i.ytimg.com/vi/KQzK5z9jkHE/mqdefault.jpg "Explained: TI-83 Linear Interpolation Program [Math]
In this video I show you how to program a linear interpolation equation into your TI-83 graphing calculator.
If you would like to see how the equation is derived, click the link below to my other video.
https://goo.gl/7OA0UU
Here is the code if you already know how to input it into your calculator:
PROGRAM:INTERP
Input X1=,A
Input X2=,D
Input X= ,I
Input Y1=,N
Input Y2=,S
Disp (((S-N)/(D-A))(I-A)+N)")
![Explained: Croccos Theorem [Taylor-Maccoll]](https://i.ytimg.com/vi/KZYHjujYpFk/mqdefault.jpg "Explained: Croccos Theorem [Taylor-Maccoll]
Croccos theorem is needed to obtain the irrotationality condition used later in the overall derivation. The equation is essentially a combination of the momentum and energy equations. The final resulting boxed equation states that the curl of the velocity field is zero, indication an irrotational flow.
The extra videos I mention in this video can be found below.
Momentum Equation: http://www.youtube.com/watch?v=ZH0fiaYGTYQ
Assumptions: http://www.youtube.com/watch?v=HIDeIZO0z-8
Total Derivative: http://www.youtube.com/watch?v=bgUDbntoXBY
TdS Equation: http://www.youtube.com/watch?v=N126SaEGuJA
Vector Identity: http://www.youtube.com/watch?v=0LO-ZcESYdE
Enthalpy: http://www.youtube.com/watch?v=yy5HQ9syrrI")
![Explained: TdS Equation [Taylor-Maccoll]](https://i.ytimg.com/vi/N126SaEGuJA/mqdefault.jpg "Explained: TdS Equation [Taylor-Maccoll]
The TdS equation is a combined statement of the first and second law of thermodynamics. It relates the entropy, enthalpy, and pressure changes in a system (for the form that we need for Croccos theorem). To keep the big picture in mind, recall that I mentioned that Croccos theorem is a combination of the thermodynamics and kinematics of a flow. This equation gives us the thermodynamics part.")
