Thanks, Ayub. It's more an exercise for Maths and Science education than a practical device like most of the other videos on KZfaq, but I appreciate your comment.

You're welcome.

Thanks Andy.

Glad you liked it, Kube!

Thank you. Hope the project goes well.

Thanks, thagrit. I didn't know that. I've always called those kinds of things struts (or ties if they're made of wire).

You are welcome, Have!

Is the paper burnt

Thanks, Mark.

Thanks, Civisme. It's a shame you hated school. Feel free to visit the LEM website to read more about science.

Thanks, Phillip.

Of course!

No problem!

An absolute focus point only exists in parabolic, that's true. But practically for a solar concentration it is not a problem to use spherical one, because the reflectors usually are not very deep ( curved ) and the solar light will be concentrated practically in the same size area as for a parabolic mirror. Parabolic mirrors are important for telescopes only.

@@poligraph841 spherical mirrors can be used in telescopes too. But below f10 they will start presenting spherical aberration.

De rien.

No problem. Thanks for watching.

You're welcome. I hope it works out for you.

Thanks Akash.

Thanks, Peter.

Thanks, oh no.

You're welcome.

Thanks, Joly!

Yes, that's probably true. However, my linear parabolic reflector is not ideal for use as a solar cooker either; it's really a science experiment for students.

LiacosEM your linear parabolic project was great but let me tell you sir that you are wrong in onething, and that is that you are actually able to cook with that linear desing if the linear parabola is made biger and with better reflected material. thanks by the way understanding this will help any one desing their own parabolic cookers i learned alot thanks againg.

Thanks Moon Night. With my simple design, my students have managed to heat up a small amount of water to about 60 degrees Celsius. Real solar cookers I've seen are usually 3D paraboloids, like satellite dishes. However, parabolas are at the heart of both, and I hope that my students learn that maths plays a big part in the design process of so many things in our lives!

Prego, Fausto.

Hey Good Afternoon, As You seems to have knowledge in this kind of Stuff. I am a reaserch person (in medical science) and I want to evaporate water from a circular dish of radius appx 1.5feet. the depth of Dish is appx 10cm. I put that dish with some active material inside it to evaporate the whole mixture. At last i get solidified mass at bottom of that dish. What I am asking is i want to fasten the evaporation of the contains with help of solar energy. Any idea how to do that. I tried this parabola but it's hard to focus the point on ground as dish is heavy and I can't keep it in middle of air hanging. Can we focus this parabola on ground , how so? Is there any other method by which is can increase the evaporation of that dish contains without fuel ?

@@brandnewayurveda1835 you need a larger dish! Large surface area of the dish larger amounts of sun energy can focused…

If you want to keep the dish to be heated on the ground, use a magnifying glass

Thanks, Abbas. Apparently, the heat we receive from the Sun averages out to about 1000 Watts per square meter on the Earth's surface. If this heat radiation is concentrated into a small area, there is significant heating. The surface area of my little experimental reflector is quite small, but my students have still managed to heat water to about 60 degrees Celsius.

Yes. If you look at the 5:30 mark of the video, you will see that the incident light will hit the parabola above the level of the focal point but it will then deflect downwards towards the focal point. For my specifications, all the incident light reflects back upwards towards the focal point except for the light that hits at -10 and at +10. These light beams reflect horizontally (with respect to the plane of the reflector). Every parabola has one focal point, regardless of how wide it is.

Thanks Kusuma.

Glad you liked it.

It sure is. I think students understand Science topics better if a little Maths is applied.

Oh i mean the controlcan

Both cans were small steel cans that we use as overflow cans. You can use any small cans!

Good question. You can try just using flat mirrors or aluminium sheets. But the sun moves across the sky so they have to be movable. Good luck.

No problem, ashtwenty12. I'd love to see your finished products.

You're welcome x 4. I'm guessing you found it useful!!

@@LiacosEM yes to build a satellite reflector

My aim was to show students how Math, Science and Engineering are all interrelated. All the tech that we use is refined and improved with mathematical techniques.

You are completely correct in your thinking. The reflector doesn't reflect light to a point (like a satellite dish would) and so it's called a "linear" parabolic reflector. My aim was teach my students about the importance of mathematics and to do a practical science activity that involves a lot of maths. However, a lot of people who actually want to design solar cookers (and related things) have found the video useful in the design process that they go through. I must admit I was surprised initially! However, the use of mathematics makes everything better!

@@LiacosEM thanks for your kick response. I was thinking about make a 3d model of a barabolic, I'll have to figure it out. Also how to manage to put this reflective metal paper on the surface without breaking it nor wrinkle it... Impossible to do it perfectly, isnt it? Heating it up would work? Thanks

two nails and a string would create an ellipse, which has two focal points.

Two nails and a string would be a straight line.

drive a nail where you want the focus to be. Tie one end of the string around that nail. Extend the dangling string downward toward you on your surface with a loose loop where you want the base of the parabola to be, and run the rest of the string vertical up the surface past the nail but attach it to the side of a 90 degree triangle square just touching the nail... Put your pen at the loop directly down toward you from the focus nail - that'll be the start of one side of your parabola... now slide the square straight to the right side and keep the pen tight against the string - as you continue to move the square, the string will slide upward and you'll trace a parabola shape... reverse it the other direction or trace the 1/2 you already did... Bob's your uncle. (since the teacher sounded ozzish (well, at least commonwealth something...)). Cheers.

It's really a science experiment to teach students the mathematics of parabolas and how they're used to focus light. However, linear parabolic reflectors are used to heat oil in a pipe that runs along the focal line. See commons.wikimedia.org/wiki/File:Parabolic_trough_solar_thermal_electric_power_plant_1.jpg. My school has a parabolic mirror and my students are really impressed when I use it to ignite paper. But teaching is not really about showing kids stuff, it's about getting kids to learn by doing stuff!!

The power of Mathematics and Science!