1. Pinhole Experiments Scott + Harrison

2. Purpose - To investigate the relationship between object distance and image height while image distance and object height are constant. - To investigate the relationship between object height and image height while object distance and image distance are constant - To investigate the relationship between image distance and and image height while maintaining a constant object height and object distance - To investigate the effects on the image by increasing the diameter of the pinhole and creating more than one pinholes

3. Hypothesis - If we decrease the object distance, then the image height will increase. - If we increase the object height, the image height will increase - If we increase the image distance, then the object distance will increase - If we increase the number of pinholes, multiple images will form - If we increase the diameter of the hole, the image will be less focused

4. Equipment/Diagram Light source for holding cards, pinhole camera (a box with one end open and the other with a translucent screen inside a larger box with one end open and a square hole in the other), arrow cards, meter stick, aluminum foil

5. Procedure 1. Cover a hole with aluminum foil and poke a hole with a pin in it. 2.Face the pinhole at a bright object (not necessarily a lightbulb). 3.Set a screen behind the pinhole for the image to be projected on. 4.Vary the distance of the object from the pinhole, while keeping the image distance from the pinhole and object height constant. 5.Vary the distance of the screen (thus the image) from the pinhole, while keeping the object distance and object height constant. 6.Vary the height of the object (arrow), while keeping the image distance and object distance constant. 7.Poke some more pinholes and observe the effect. 8.Increase the size of a pinhole and observe the effect.

6. Hi vs Do Hi is proportional to 1/Do

7. Exp 1 Mathematical Analysis + Error Exp 1: Image Height-->Hi, Object Distance-->Do, (Di and Ho are held constant) Hi α 1/Do Hi = k*1/Do k = 0.01455m^2 (calc by Logger Pro) Hi = 0.01455m^2 * 1/Do h i = h 0 *d i * (1/d 0 ),slope = h 0 *d i =.085 m*.165 m =.01403 m 2 Accepted Value=.01403 m 2 Experimental Value=.01455 m 2 Absolute Error = | Acc-Exp | Absolute Error=|.01403 m 2 -.01455 m 2 | Absolute Error=.00052 m 2 Relative Error= Abs /Acc Relative Error=.00052 m 2 /.01403 m 2 Relative Error= 3.71%

8. Hi vs Di Hi is proportional to Di

9. Exp 2 Mathematical Analysis + Error Exp 2: Image Height-->Hi, Image Distance--> Di, (Do and Ho are held constant) Hi α Di Hi = k* Di k = 0.1543m/m (calc by Logger Pro) Hi = 0.1543m/m * Ho h 0 =.085 m, h 0 =.56 m h i = h 0 /d 0 * d i,slope = h 0 /d 0 =.085 m/.56 m =.1518 Accepted Value=.1518 Experimental Value=.1543 Absolute Error = | Acc-Exp | Absolute Error=|.1518-.1543| Absolute Error=.0025 Relative Error= Abs /Acc Relative Error=.0025 /.1518 Relative Error= 1.65%

10. Hi vs Ho Hi is proportional to Ho

11. Exp 3 Mathematical Analysis + Error Exp 3: Image Height-->Hi, Object Height-->Ho Hi α Ho Hi = k* Ho k = 0.8527m/m (calc by Logger Pro) Hi = 0.8527m/m * Ho Exp 3 Image Height vs Object Height d i =.165 m, d i =.20 m, d 0 =.56 m h i = d i /d 0 * h 0,slope = d i /d 0 =.165 m/.20 m =.8250 Accepted Value=.8527 Experimental Value=.8250 Absolute Error = | Acc-Exp | Absolute Error=|.8250-.8527| Absolute Error=.0277 Relative Error= Abs /Acc Relative Error=.0277 /.8250 Relative Error= 3.36%

12. Similar Triangle Proof

13. Ray Diagrams Original Increasing Object Distance, Decrease Image Height If we increase the object height, we increase the image height. All ray diagrams are based on idea that light travels as a straight line. If we increase the image height, we increase the image distance

14. Ray Diagrams Multiple Pinholes Bigger Pinhole Multiple Images Blurred

15. Animation http://www.phy.ntnu.edu.tw/ntnujava/index.php ?topic=38.0