laser laws reflection

For this milestone we were supposed to make a laser display in a form of a right angle triangle.  This helped me apply what we had learned about light, reflection, angles and what a right triangle is (Pythagorean theorem).

Laser Display!

The first thing we had to do was make a design for the laser display. We decided to make an Angry Birds design. We originally wanted to make three different characters, but because of limited mirrors we had to only use one and we had to take away a lot of the mirrors and lasers that we originally had.  The design was a lot simpler, we could do it with the materials we had, and our first design might not have fit, anyway.

We measured and marked our project and it was approved because it was in a box so it didn’t get into anyone’s eyes. Once we powered the laser up with the batteries we found that the design worked even though it was faint.

Our display included a right angle triangle on its beak. We know that because we measured it with protractors for angles and rulers for the length. Our measurements showed that it was a true right angle.

We checked to find how accurate the Measure app was. First we used the app to measure the lengths again, then we used the percent difference formula on some of the measurements to see how accurate it was in different situations compared to a ruler. We made the conclusion that the app was tricky to get precise, but when we got it into the right spot, it was fairly accurate.

What led to the laser display…

Milestone 1 – Mindmap

I made a mind map using MindNode, with my thoughts about LIGHT, and some questions and examples, and tried to answer some of the questions.

Milestone 2 – Pythagorean Theorem

We learned about the Pythagorean theorem, which means I can understand the relationship between the three sides of a right angle triangle and calculate their measurements and angles using the formula

Milestone 3 – Law of reflection experiment

We were supposed to use the scientific method to create a lab experiment to test the law of reflection. I checked whether the Pythagorean theorem could be used for all triangles or just right angle triangles.  We tested lots of different types of triangles by measuring them with rulers and protractors. Then we checked to see whether the Pythagorean theorem applied to any of them.  I found that it only applied to triangles that were right angled (one angle of 90 degrees)

Milestone 4 –  Laser Triangle Design

I made a right angle triangle using Notability, using the law of reflection to make a right angle and another reflection to make a triangle. Then I used the Pythagorean theorem and my measurements to confirm that it was a right angle triangle. I had to do this one a few times to get it correct.

Milestone 5 – Laser Triangle Design

See above!  Everything led to the laser triangle presentation. And this blog.


For applying and innovating

This competency is about cooperatively developing projects. We developed a scientific experimental procedure, applied it and learned more about the law of reflection and the Pythagorean theorem and how it worked, using the materials we had. An example of this, is how, when our project looked like it wasn’t really going to work as we hoped, Aaron and I worked to adapt it by cutting down on how many mirrors it needed and also by deciding how the lasers were placed so they worked and didn’t get in the way of the other lasers or the reflections. I think I worked well on this because we ended up finding what design worked best with the project and the limited mirrors that we used.

For questioning and predicting

This competency is about demonstrating sustained intellectual curiosity and also about working well with the group to do the project. I think I got sidetracked sometimes, but still did okay and was interested the whole time. For example, we kept working hard on the changes that needed to be made, and finishing the project so it worked. We originally thought that we would have to do the angry bird in 11 mirrors, but we managed to do it in less, 6 in fact.

For communicating and representing

This competency is about bringing math to life by making a design or prediction into a real thing. To make this project work we had to have a good process, and make sure that we ended up with a right triangle and that we had all the right measurements. An example of this is how we worked really  carefully and were precise, and then we even checked the lengths and angles again using the Measure app. I think I did good work on this because by having a good design and careful work, we ended up with a working reflected laser right-angle triangle. I liked how the design looked when we were done.


I think this was pretty fun to complete (and for Milestone 4, really annoying) and I learned a lot about the scientific method, Pythagorean theorem, law of reflection and a lot of facts that I didn’t know about light. The last thing that I learned was that it’s really hard to know where light is going to go when it bounces off a mirror – so hitting a water jug with a reflected laser was really really hard.