“Camera obscura Lab Report day”

9.9.11.

Wiki:Notes and worksheets and some keys (see “teacher websites”)

Hand in Worksheet “finding the diameter of the sun” by 3 PM today into the “Bin”

Camera Obscura Problem worksheet is HW

Syllabus coming on Monday!!

Use a pinhole in a card to find the

diameter of the sun

• Change km to meters

• Change cm to meters

• Find diameter of the sun

• (height of the object) hi = - di

ho do hi

di

do

ho

Skip #3Change all units to meters

Height of imageDistance to image

Distance to the object = distance to the sunHeight of image (-) because it is real

hidi

hi = - di

ho do

Problems

• Work problems for both sets of data on the back – Show your work– Equation– Substitution– Answer– Label

FYI: 1 meter = 100 cm 1 km = 1000 meters

• Magnification– No Label on Magnification– Real image the magnification is a negative– Magnification is < 1 if the image is smaller– Use:

M = hi or M = -di

ho do

Hi =???

Ho =190 cm

Di = 6.2 cm Do= 438 cm

M = hi = - di

ho do

The height should be (-) because it is a real imageLabels should all be the same

The first answer is -2.69 cm The second answer is -0.014

hi = - di

ho do

Camera Obscura Lab Report

Take your data from the 3 objects you viewed in the Camera obscura and enter in the data table

For this lab, Pringles can is 23 cm long

Height of the image (-)Height of the Object is (+)

Magnification is (-)

hiho

dido

M = hi = - di

ho do

Rays are straight lines of lightNotice that the rays from each edge of the object cross exactly at the

pinhole when it is very small

Be sure to draw in the image in the diagrams!!

hiho

dido

M = hi = - di

ho do

What happens to the image when the object is closer to the pinhole?

hiho

di do

M = hi = - di

ho do

When the pinhole is larger, More rays enter the pinhole from each spot on the object, What effect does that have on the image?

Would the image be more or less clear?Would the image be more or less bright?

Syllabus on Monday!

Camera Obscura lab is due Tuesday at 3 PM,

If you are finished early, you may place your lab with your name and hour in the “BIN”

You will have time to ask questions on Monday, but not on Tuesday during classt ime.

Camera Obscura Problems worksheet is Homework (Write: HW ) on top of paper

You may engrave your name on your calculator