Refraction in Water
Channel: India Literacy Project
Date: 2019-09-10

Concept Covered:
Refraction of Light.

Grade and Chapter Name: 
Grade 7- Light
Grade 8- Our Colourful World
Grade 10- Light – Reflection and Refraction 

Things You Will Need:
1. Bowl/cup
2. Water
3. Coin

Set Up: 
1. Place a coin in a cup and walk away from cup till the coin is no longer visible to you. 
2. Now, ask a friend pour some water in to the cup without moving the coin. 
3. You will notice the coin gradually starts reappearing before becoming fully visible. How does this happen?

Concept:
In this experiment, the coin gradually reappears as water is poured into the bowl.

When there is no water in the bowl, the medium inside and outside the bowl is the same- which is air. Hence, the ray of light from the coin does not bend when it comes out of the bowl. Hence, the coin is not visible to the viewer. 

When the bowl is filled with water, the ray of light from the coin starts bending when moving from water to air, towards the eye of the viewer. Hence the coin gradually starts becoming visible.

When the bowl is full, the coin becomes fully visible to the viewer now, even though its position has not changed, because of the bending of the ray of light.

Observe:
Observe the distance at which the coin disappears when stepping away from the bowl.

Related Topics:
Refractive index of various media.

Try This:
Does adding colour to the water, stop the coin from reappearing when the bowl is filled?
Try this experiment, with any old or used cooking oil. Standing in the same spot, are you able to see the coin as you did with water?

CAUTION: 
Experiments involving the use of sharp objects (knife, scissors, cutter, pins, etc.), or fire (spirit lamp, candles, matches) or any chemical must strictly done under the supervision of a Teacher or responsible adult. 
Chemistry experiments must be done in a well-ventilated room and Teachers must keep in mind if students in the class have any specific allergy that can be aggravated by fumes, smells, etc. 
Fill the spirit lamp only with surgical spirit easily available at medical stores or pharmacies. DO NOT fill it with any other type of fuel.

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About India Literacy Project:
India Literacy Project, ILP, is a volunteer based non-profit organization dedicated to the cause of literacy in India. By empowering every individual we serve with functional literacy and an understanding of their basic rights and responsibilities, we strive to be a catalyst for 100% literacy in India.

About MDLS:
ILP's Multi-Dimensional Learning Space (MDLS) is a program that provides learning opportunities to school children to explore, experiment, discover, and learn in multiple ways.

The concept of Schools as multi-dimensional learning spaces is based on the foundation that 1) Equal importance should be given to all aspects of the curriculum 2) Learning is not restricted to a curriculum. It should extend to help holistic and balanced development of a child 3) One learning style doesn't work for all and 4) Learning should involve visual, auditory and experiential methods.

About MDLS Science Experiment Kit: 
The Science Experiment Kit is one of the key elements of ILP’s Multi-Dimensional Learning Space (MDLS) program. MDLS has been enabling students to learn Science through hands-on experiments, showing learning Science can be simple, fun, inexpensive and can be done with items you can easily find around you, without many specialized or expensive equipment. The Kit contains material required to do experiments covering around 200+ concepts from 5th to 10th Grade across Physics, Chemistry and Biology.