My PBL Project

INVESTIGATION PART

1. How does the rectilinear propagation of light play a role in pinhole cameras?

Rectilinear propagation of light is the fact that light travels in a straight line. A lit up object reflects rays of lights in various directions. These rays keep traveling until they hit something. In a pinhole camera, they go through the small hole in the front and expose themselves onto the paper inside, thus painting a picture. The smaller whole allows the image to be more in focus as the path the photons travel becomes small.

2. Why is it important to shield the paper or film from light after the picture is taken until it is developed?

It is important to shield the paper or film from light after the image is taken until it is developed to prevent the light from painting another, extremely out of focus image onto the paper. If other light is exposed to it, the original image would be disrupted. Once developed, the picture would either come out blank or completely black.

3. Why do the pictures come out upside down on the camera?

Light travels in a straight line unless something deflects or absorbs it. So, when an image is taken, the bottom part of the subject gives of photons, which are particles of light, that try to reach the pinhole by going upwards diagonally, thus reaching the top of the photographic paper. However, the light on the top has to travel down to pinhole. It also travels diagonally (but down instead) and hits the bottom of the photographic paper inside of the camera. This causes the image to come out upside down.

4. How could you make the negative image that was developed into a positive?

One could take a picture of the picture, and use their phone or computer image editors to convert the negative to a positive.

On the other hand, a negative could be turned into a positive by using other methods as well. An example of this would be placing the negative image on top of a new photographic paper, putting a clear and transparent glass on top of them, and exposing them to light (such as placing them under a lamp). Then, the new photograph would need to be developed similarly to the negative by using a darkroom, a developer solution, and a fixer/stopper solution.

• A roll of ductape

• A knife

• A pair of scissors

• An aluminum can

• A black poster board

• Glue

• A needle

• A piece of photographic paper

• A pen or pencil

• A ruler

• A rubber band.

• A red light

• A pair of tongs

• A graduated cylinder

• 2 beakers

• A funnel

• 2 containers

• About 600 ml water

• 2 teaspoons of coffee powder

• 2 teaspoons of baking soda

• 2 packets of vitamin C drink mix

• 5 ml of lemon juice

• 4 sheets of paper

• A pot

• A stove

PROCEDURE

1. Get your 2 sheets of printer paper and pen. Then, draw out a template for your box onto the paper. For this, you will need to draw out six squares and small flaps. One of the squares should be separate from the rest. This will be the lid.

2. Next, paste your template on the poster board using glue and cut it out using scissors or the knife. Cut a whole in the center of the square that will be opposite to the lid.

3. Cut out a square from the aluminum can about 3 by 3 cm using scissors.

4. Make a hole in the aluminum square using a needle.

5.Then, tape this square behind the hole in the box.

6. Now, fold and glue the flaps together to form a box.

7. Cut out a small rectangular piece of black card.

8. Now, put ductape on all of its sides.

9. Tape this in front of the whole.

10. Now, put the photographic paper (cut to fit) inside the box, opposite to the hole. Feel free to tape it down.

11.Rubber band the lid on the box. You have now made your pinhole camera.

12. Calculate the distance you will need to stand from the subject you plan to photograph. Measure the dimensions of the object using a ruler. Use the formula: i/f=o/d to calculate this distance. In this case, i represents the height/width of the photo paper, f represents the focal length, and o represents the height/width of the object.

13. Take the picture by opening the flap for around 30 seconds and letting the light paint a picture onto the photographic paper.

14. Then, make your coffee by putting the coffee powder and water in a pot and letting it brew. Let it cool for a few minutes.

15. Mix in 2 packets of vitamin C drink mix into 200 ml of water in a beaker. Add 2 teaspoons of baking soda into this and stir it in.

16. Measure out 200 ml of the coffee into a beaker. Pour this and the vitamin C mixture into a container.

17. To make the stopping solution, mix in 5 ml of lemon juice and 200 ml of water.

18. Now, get your darkroom ready. For this, you will need to make sure that all light from the outside is blocked and remove all lights that are not red, replacing them with a red light if wished for.

19. Take out the paper from the camera using tongs and dip it into the coffee and vitamin C solution. Keep it there for around 3 minutes.

20. Then, transfer the paper in the lemon juice and water solution for 30 seconds.

21. Take the photo out and set it out to dry.

You have now taken and developed a photograph.

SAFETY

Be sure to be careful and even have adult supervision when handling the stove, knife, and scissors.

SCIENTIFIC PRINCIPLE/ ESSENTIAL UNDERSTANDING.

In this project, I made, took a picture, and developed an image from a pinhole camera. A pinhole camera is a dark chamber which utilizes rectilinear propagation of light, which means that light travels in a straight line, to paint images with light.

A red light was used when developing an image so that the image wouldn't be disturbed by unsafe wavelengths.

The developer solution of vitamin C and coffee converted the silver ions in the photographic to silver, while the fixer helped that chemical reaction "stay" for a longer period of time.

REAL LIFE CONNECTION/FURTHER APPLICATIONS

Pinhole cameras are still used to take photographs in many different countries. They are used when people wish to take old-looking pictures with older methods. Photographers worldwide develop these images in darkrooms similarly to how I did in the procedure. The pinhole camera benefited society when it was made, and continues to do so even now. The world's first image was taken using a pinhole camera. Pinhole cameras stimulated the inventions of various different photographic technologies. Pictures help us capture memories and faces of people we love, and relive them by simply viewing them later on. A picture is worth a thousand words. Using pictures to record information is highly beneficial when words alone fail us.