# Investigating optical properties of Jelly.

Candidate Name:

Session: May 2015                 Page |

International Baccalaureate Diploma Program (IBDP)

Session: May 2015

Physics HL Lab Report

Lab Report Title: Investigating optical properties of Jelly.

Criteria Assessed:

• Design (D)

Candidate Name:

Candidate Number:

International School, Singapore

RESEARCH QUESTION: What is the relationship between the temperature and the refractive index of Jelly?

INTRODUCTION:

When a beam of light of any wavelength travels, it bends towards or away from its normal and this phenomena is known as refraction. The refractive index, n, is given:. While travelling from less to a more optically dense medium, the beam of light slows down and bends towards the normal and while travelling from a dense to a less optically dense medium, the beam of light speeds up and bends away from the normal.

Strawberry Jelly is an optically denser medium compared to air and hence, when an incident beam of light travels from air into the Jelly, it slows down and bends towards the normal. In this investigation, the refractive index of a translucent cube of strawberry Jelly is investigated. Regardless of the ingredients, Jelly is formed by crystallization and the rigidity of the structure of the crystals is dependent on its temperature. Thus, the temperature can alter the optical density of Jelly as a result of which, the refractive index of the translucent cube of Strawberry Jelly changes with temperature. Hence, the research question that this experiment aims to answer is “What is the relationship between the temperature and the refractive index of Jelly?

To form the Jelly, a sachet of ready-to-make strawberry Jelly was used and all instructions on the packet were followed to obtain a well-made Jelly. An electronic water bath was used to keep the jellies at different temperatures. As the Jelly is heated, the water in it would expand and thus, it was hypothesized that higher the temperature, lower would be the optical density of the Jelly and hence, smaller the angle of refraction and the refractive index.

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APPARATUS AND ...