I think in this experiment the periscope is gonna reflect things on the mirror, by using the light outside and reflect it on the top mirror and after the top one reflect things on the bottom one by placing it 45 degree angle, which we can see by our eyes. I will be also adding an extra step on it, by making a thing to lower or higher the height. Every person have different height or in a different surroundings, there is away somethings that are hard to see, but if you use a periscope, it will be much more easy to see things, either higher or lower. This project is base on the reflection of light. 

I did research on what is the purpose of periscope and also how does the periscope works.

The purpose of periscope is basically for the submarines to determine what is in their surroundings, and also to observe some chemical reaction. Their purpose in the military is to observe their hiding position and for tanks and armoured vehicles to check all around the area. 

Their use it’s for to observe a farther vision without moving, and also get a closer view of things.

Design variables:

Features: The key function of my build was to use it to look around. 

Functionality: My build works as a mirror reflecting to the other.

Aesthetics: The looks of the build is not very good, because I use recycling materials.

User Experience: It was easy to use my build, it's basically just looking through the whole which lead to the mirror.

One or two box, two piece of mirror, hot glue gun, straw, scissor,
This experiment is to make a periscope:
By first finding a perfect box or make a box, the same width of your mirror and high enough for your mirror to fit in by 45'C.
I make a box to fit inside of the other one, because the one that  I make you can pull it up or down. 
One of my box have a long hole in one side of the box. You can cut it or find one.
After calculus a measurement of a triangle to make sure the mirror doesn't fall.
Cut the triangle out.
For the box that I make, there's two layer, so I make sure the layer inside is shorter then the one outside by the measurement of the triangle, because this will help me by easier to stick the mirror on. 
After, I glue threes sides together and try does it work by holding the mirror on to the box, one of the mirror is facing down 45' and at the top of one of the box, and the other one facing up 45' at the bottom of the other box.
Then if it work glue the triangle one at the top of the first box, and the other one at the bottom of the other box.
After gluing the triangle make sure they are not falling and glue the mirror on to it, make sure is not falling also.
Next test it does it work again, after cut a straw by the side you want the handle to be, cut eighth legs(like octopus) on one side of the straw and cut a hole in the other box that doesn't have a long hole in the middle(for the straw to fit in) at the oppies side of the mirror and also the same side as the long hole on the other box.
After cutting a hole, put the straw inside the eighth legs inside and the side you didn't do anything outside.
Stick the eighth legs on to the box, it kind of just for attaching to the other box, because it's too heavy, so you can't actually use it.
Finished the final touch by gluing the fourth side on to the box that you didn't finished yet.
And finally put the box with straw to the other one, put the straw in the hole first, after try to stuff the box in, and here it is finished.
Try to look through it, see does it work.

The periscope does work, but it may be hard to see, it's doesn't look like a periscope from the outside, but it works.

I try it to not put it in a form of 45 degree angle, and it does works, but the periscope won't be straight, you will need to hold it diagonally and it also will be harder to see.

The purpose of periscope is basicailly for people to look in a very different way, such as under the sea, above your points of vue and maybe sometimes to observe your surroundings.

For it's to work, it need a mirror on top that's facing down and also facing the side, so it's 45 degree angle, and there has to be one mirror on the bottom also 45 degree angle, but this time is facing up and also side, this will help the mirror to reflects things one to the other and now you can see it by the mirror below.

The result was what I expected at the start, the top mirror reflect things to the bottom one, which we can see.

The conclusion was for the question "What is purpose of periscope?", after trying it I realize, we really need light to look at the periscope or you won't see anythings. When the light reflect in to the periscope on the bottom mirror, and soon it reflect on to the top one, and reflect it in to our eyes. Our eyes adapt seeing light, so when we close the light, at first you won't see anything at all. After you will start seeing a bit. This makes when I was in an area that have light on, and trying look under my bed with no light under it, it will be hard to see.

This object is use when you want to look or observe around. It for people to look up or down, such as under a bed, a table and it's normally put on a submarine, for the people inside to look what is up on top of them.

It was not what I expented from the looks and the desgin, I thought it was gonna be a shape out of a "Z", but it's tured out to be like an "I". And the looks it's don't pretty good.

What is the purpose of periscope?

https://www.vedantu.com/question-answer/periscope-works-on-the-principle-of-a-refraction-class-11-physics-cbse-5f23b5d79e1c9d6bce51b943

How to make a periscope?

https://www.wikihow.com/Make-a-Periscope

Thank you for listening/reading my presentation.