Video narration
Gilas ke pani mein seedhi rakhi straw beech se mudi hui kyun dikhti hai? Upar ka hissa seedha dikhta hai, lekin pani ke bheetar wala hissa thoda khiska hua sa. Kya pani ne straw mod di? Nahin, straw apni jagah seedhi rehti hai. Doobe hue hisse se aati roshni pani se hawa mein nikalti hai. Pani aur hawa mein roshni ki chaal alag hoti hai. Seema ko tirchhe paar karte samay uski chaal badalti hai, aur disha bhi mud jaati hai. Disha ka yeh badlav apavartan kehlata hai. Lekin roshni agar seema ko bilkul seedhe paar kare, to chaal badalne par bhi disha nahin mudti. Ab badli raah se aayi roshni aapki aankh tak pahunchti hai. Aankh use seedhi rekha mein aaya maanti hai, isliye pani ke bheetar ka hissa apni asli jagah se hatkar dikhai deta hai. To gilas mein straw mudi kyun lagti hai? Pani se nikalti roshni doobe hisse ko khiska hua dikhati hai - straw nahin mudti.