A Magnifying DiscoveryA Magnifying DiscoveryPhysics (Fall 2013)By: Isabella Alvia

Physics (Fall 2013)By: Isabella Alvia

Table of Contents...✦ Introduction: Optics and Magnification

✦ Applications and Examples: Optics

✦ Applications and Examples: Magnification

✦ Question

✦ Hypothesis

✦ Materials

✦ Procedure: Steps to constructing the apparatus

✦ Experiment

✦ Data (of magnifying glass)

✦ Data (of nearsighted lens)

✦ Magnification Calculations

✦ Conclusion

✦ Sources

Introduction: Optics and Magnification

✦ Optics is a branch of physics which studies the properties of light and how it behaves when travelled through certain objects/ matter.

✦ Optics are widely used to aid the human eye to see various objects clearer than if it were to view the object alone.

✦ Magnification refers to the process of enlarging an object in appearance, not physically.

✦ Magnification enables one to increase the resolution of an objects appearance to help get a better visualization.

Applications and Examples: Optics

✦ Applied in science: Astronomy, photography, medicine, etc.

✦ Everyday objects: Mirrors, lenses (glasses- to help us view near/ far), and a magnifying glass.

✦ Example: Looking through a glass filled with water. Objects through glass appear smaller due to light refraction.

Applications and Examples: Magnification

✦ Application: Magnifying lens is used to compare the apparent size (through the lens) over the actual size (real, physical size) of the object.

✦ Equation: Magnification = Apparent Size/ Actual Size

✦ Magnification may vary depending on its optical distance (how close the lens is to the object).

✦ Applications in everyday technology: Microscopes (to enlarge tiny objects in detail) and telescopes (to see far objects closer).

Question

✦ If I increase the height of the magnifying glass/ lens, will the object appear bigger or smaller through the lens?

✦ What happens if I change the magnifying glass to a reading lens or a nearsighted lens.

Hypothesis

✦ If I increase the height (greater optical distance) of the magnifying glass, then the object’s measurement would decrease.

Materials✦ A sturdy ruler

✦ Tape

✦ Little strip of paper

✦ Black marker

✦ Scissors

✦ 4 small objects: penny, short string, sim card, and a paperclip

✦ A magnifying glass

✦ Box (used as support to hold the ruler straight)

✦ Rubber band/ tie (used to hold the magnifying glass in place on the ruler and to make it easier to adjust its position).

Procedure: Steps to constructing the

apparatus✦ Start by taking the little strip of paper

and measure it according to the diameterof the magnifying lens using the ruler and tape it along the lens of the magnifying glass.

✦ Construct the support of the magnifying glass by taping the ruler to the box.

✦ Attach the magnifying glass using the rubber tie.

✦ Perform same steps except replace the magnifying glass with a nearsighted lens,then compare results.

Experiment

✦ I started off by measuring the object’s actual size. Once I noted the measurement, then positioned the magnifying glass starting at a 6cm height.

✦ I then looked at object through the magnifying glass, measuring it’s apparent size, with each time changing the magnifying glass’s position (ending at 24cm).

✦ I repeated this step for all 4 objects and kept track of my results using a data chart.

Data: Magnifying Glass (observations)

✦ I noticed that as I first positioned the magnifying glass of each object at 6cm, its apparent size was about double the actual size.

✦ Once I began increasing the optical distance (positioning the magnifying glass higher and higher, further from the object), the object’s apparent size began to decrease.

✦ At 24cm, the object’s apparent size appeared to be less than its actual size.

Data: Magnifying glass

Object Actual Size (cm) Height of lens

(cm)

Optical size (cm)

Paperclip 2.8cm cm 6cm 4 cm

12cm 3 cm

18 cm 1.5 cm

24cm 1cm

Short string 1.7 cm 6cm 3 cm

12cm 2cm

18cm 1.5cm

24cm 0.5cm

Sim card 1.5 cm 6cm 3cm

12cm 2cm

18cm 1cm

24cm 0cm

Penny 2 cm 6cm 2.5cm

12cm 1.7cm

18cm 1cm

24cm 0.5cm

Data: Nearsighted Lens (observations)

✦ I observed that as the lens was closer to the object, its image through the lens was almost similar to its actual size.

✦ As I placed the lens at a higher level, increasing the optical distance, I noticed the measurements of the objects through the lens were shorter.

Data: Nearsighted lens

Object Actual Size (cm) Height of lens

(cm)

Optical size (cm)

Paperclip 2.8cm cm 6cm 2cm

12cm 1.3cm

18 cm 1cm

24cm 0.6cm

Short string 1.7 cm 6cm 1 cm

12cm 0.7cm

18cm 0.5cm

24cm 0.2cm

Sim card 1.5 cm 6cm 1cm

12cm 0.5cm

18cm 0.4cm

24cm 0.1cm

Penny 2 cm 6cm 1cm

12cm 0.7cm

18cm 0.5cm

24cm 0.2cm

Calculations✦ Calculating magnification:

{magnification= apparent size/ actual size}

✦ Paperclip: 4/2.8= 1.4 (6cm), 3/2.8= 1.1 (12cm), 1.5/2.8= 0.5 (18cm), 1/2.8= 0.4 (24cm)

✦ String: 3/1.7= 1.8 (6cm), 2/1.7= 1.2 (12cm) ,1.5/1.7= 0.9 (18cm), 0.5/1.7= 0.3 (24cm).

✦ Sim card: 3/1.5= 2 (6cm), 2/1.5= 1.3 (12cm) , 1/1.5= 0.6 (18cm), 0/1.5= 0 (24cm)

✦ Penny: 2.5/2= 1.3 (6cm), 1.7/2= 0.9 (12cm), 1/2= 0.5 (18cm), 0.5/2= 0.3 (24cm)

Conclusion✦ As the magnifying lens was placed closer, the object’s

apparent size increased/ doubled. This is mainly due to the fact that objects normally appear larger when a magnifying glass is placed closer. Our eyes follow the light rays to the virtual image. Therefore, when observing an object through a magnifying glass, we are viewing the image of the object. However, this changes when we view objects through a magnifying glass with a larger distance between because a magnifying glass only enlarges the image when placed closer to the object, it no longer works when placed further.

✦ Nearsighted lens are made to assist in viewing far away objects clearly. Unlike the magnifying lens, when the nearsighted lens was placed at a distance closer to the object, its measurement (through the lens) decreased. Even though we place the lens closer and closer to the object, it will not enlarge, but will maintain its actual size. Farsighted lens such as reading glasses would have similar results to a magnifying glass compared to a nearsighted lens.

Conclusion (cont.)

✦ In conclusion, my hypothesis was correct. When the distance between the object and the magnifying lens was increased (further apart from each other), the object’s measurement decreased.

Sources1."Olympus Microscopy Resource Center | Anatomy of the Microscope - The Concept of Magnification." Olympus Microscopy Resource Center. N.p., n.d. Web. 23 Sept. 2013. <http://www.olympusmicro.com/primer/anatomy/magnification.html>.

2."A Magnifying Discovery." Science Fair Project Ideas, Answers, & Tools. N.p., n.d. Web. 23 Sept. 2013. <http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p021.shtml#materials>.

3."Lens Magnification." Magnification. N.p., 3 July 2013. Web. 23 Sept. 2013. <http://www.mystd.de/album/calculator/magnification.html>.

2."Spherical Lenses." The Physics Hypertextbook. N.p., n.d. Web. 23 Sept. 2013. <http://physics.info/lenses/>.

3."Magnifying Glass Lens | Large Magnifying Glass | ." Tutorvista.com. N.p., n.d. Web. 23 Sept. 2013. <http://www.tutorvista.com/physics/magnifying-glass-lens>.

4."Image Characteristics." The Physics Classroom. N.p., n.d. Web. 23 Sept. 2013. <http://www.physicsclassroom.com/class/refln/u13l2b.cfm#mag>.