Linear Parabolic Solar Reflectors: A Practical Experiment for Students

In this practical activity/experiment, students will learn about parabolas, make a parabolic solar reflector, and then investigate its ability to focus sunlight.

[juantamad]

... explanation is as clear as the bright Sun... great job and thank you for sharing.

[ayubasghar]

THE BEST VIDEO OF PARABOLIC MIRROR CONSTRUCTION ON THE NET, as far as I have searched, THANKS A LOT, GOD BLESS

[AndymacA]

Best explanation I have seen, having the maths explained makes all this far easier to understand.

[buzzwerd]

A half ellipse containing 1 vertex will focus straight light coming in onto that vertex. A lot of car headlight reflectors are elliptical, check a car parts store or junkyard.
When you make a trough reflector, run a pipe along the axis and heat water in that.

[DenBlackburn]

I made a Linear Parabolic reflector way back when I was in school so I could use it as a directional beam antenna for my CB, I pointed it in the direction of my friends CB antenna, it worked fantastic, (no good if you wanted a group chat) as I only wanted to talk to him, it did the job, that was about 40 years ago, eek!

[iandale]

Brilliant thanks, I’d just ordered some mirror card and wondered how to set up the parabolic frame to hold it in place.

[abosain]

Thanks for the illustration, you solve the y-axis point. But still the focal point on the z-axis need to be calculated to set it outside the 3D parabolic receiver!

[XoshBitt]

I'm horrible at math but i'm interested to make my own parabola. Thank you so much for teaching this in a way that is simple an practical. I love now knowing how I can adjust the focal point. Thanks a lot for this video. Looking at your website too.. very interesting stuff.

[ElysianDreams]

I have always used the formula "depth = radius^2/(4*fp)", where fp is your desired focal point distance. Radius squared (x dimension squared) divided by 4 times desired focal point distance. Remember to use the same units for x and y
Example: fp = 72 r = 30 = 900/288 = 3.125 depth

[OnHoldAt]

Yup, good one. I'll be back when I'm ready for this stage of my solar project. Materials will increase in quality and ability, but the principles you outlined are exactly what this DIYer needed. Thanks.

[kumardigvijaymishra]

Thanks for giving working numbers. I shall get back to finding some supplies and much needed material. I suppose both mugs were made of anodized metal with black paint for maximum absorption?

[Dendritic]

Great! How about Mylar (from emergency blanket) instead of aluminum foil?

[LabradorLeader]

The parabolic trough you made has many (an infinite number !) of focal points along a line, instead you only placed the paper stick touching a small part of that line which you called the focal point. If you place another paper stick at right angles to the existing one at its tip (to form a letter 'T'), you will trace out the focal line with the top of the T.

[LifesVoyager]

If you take a reflector such as this one, and point it straight up at the cloudless night sky, will it focus the absorption effect of the black body absorber that is space?

[sassysisplays]

Sir can you tell me the materials involved in it? Means the materials you used especially which cup you have used?

[tmahmood]

Will you please tell me the focal length of an hyperbolic mirror.

[abbasamro]

Good job dear, i would like to know what the equation that help me to know the concentrated resultant heat temperature ?.

[Kube_Dog]

Very nice. Brought back some schoolin' from long ago. Well explained and demonstrated. And kept simple at the same time.

[giovannig.]

Is it possible to build a telescope with two linear parabolic mirrors? Instead of one "3d" parabolic mirror + one plane mirror...

[civismesecret]

You are a very good teacher.. I hated school but if I could have a teacher that explain with baby-steps like you did, I would love it. Thx !!