Thanks Qi Xuan Lai for sharing your work as part of the Young Water Ambassador Programme
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Refraction of light means that the light travels at a different speed in a substance, or in this instance, water. In this case, light travels faster in air than in water, so when you stick a stick into a glass of water, the stick looks "broken" because the light reflecting off the pencil is travelling faster in air than in the water. 
Hence, when looking from the top and from the bottom, there is a difference. 
The top two drawings are when there is no water in the cup. The bottom two is when the cup is half-filled with water.