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A straw looks "bent" when it's in water because water causes light to "change course" when it moves from air into the water. The light will again be caused to change course when it leaves the water to go back into air. This is called refraction. Refraction is a fundamental property exhibited by a wave that changes mediums through which it is traveling.
Or, making it simple..
A straw seems bent because water is denser than air, so when it changes from air to water is applied it seems bent.
Wiki User
∙ 8y ago
Wiki User
∙ 15y agoYou see the straw because light is reflected from the straw into your eyes. Your brain calculates where the straw is by assuming the light came in a straight line from the straw to your eye. For the part of the straw out of the water your brain is correct. But for the part of the straw in the water the light gets bent when it leaves the water (because light bends when it goes from one medium to another) and tricks your brain into thinking it started somewhere else. So the brain calculates the submerged part of the straw to be where it really isn't and the straw looks disconnected. This same effect happens with a rock at the bottom of a pool. If you try to pick up the rock it won't be exactly where it looks like it is. Really neat stuff.
Wiki User
∙ 14y agoA straw appears bent in a cup of water because of refraction. The waves when hitting the water appear to bend making the straw really look like its bending when really its just the waves hitting the water and appearing to bend
Wiki User
∙ 12y agoThe illusion occurs because light, unlike rigid straws or pencils, really does bend dramatically as it goes from one material into another, such as air into water. This bending is called refraction. How it works: At the surface of each new material it strikes, light suddenly changes speed. Why? Each material is more or less dense than the other.
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∙ 10y agoThe SPOON looks broken because the light coming through the water moves at a different speed than light through water.
Sara Playz
Gabe Teves
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∙ 11y agoBecause the angle of incidence AT YOUR EYE is different depending on weather or not the light started above or below the water surface.
Wiki User
∙ 15y agoRefraction...or the bending of light.
Wiki User
∙ 13y agorefraction
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What happens when you drink through a straw?
This question points up some key misconceptions about what a vacuum is.So you put a straw in your cup of water. If you look down the straw or could look through it, you would see that the level of water inside and outside the straw are exactly the same. This is because the atmosphere is pushing down on the water inside the straw, and it is pushing down equally hard on the water outside the straw. So the pressures are equal.When you suck on the straw, you are decreasing the pressure in your mouth and lowering the pressure of the air in the top of the straw. When that happens, the force of the atmosphere pushing on the water in the glass is higher than the force of gas inside the straw. The atmosphere forces the liquid up the straw into your mouth. So, in essence, you ARE NOT sucking the liquid into your mouth, the atmosphere is pushing it there.This is easily proved by an experiment. Try drinking water from a straw that is more than 20 meters tall. It won't work. At around 20 meters, the massive column of water inside the straw would be pulled down by gravity, with a force greater than the upward force caused by the atmosphere. Even if you completely evacuate the straw with a high-powered pump the water won't make it up the straw. This is why you can't pump water out of a well that is more than 20 meters deep in the ground. Anything deeper than that and you need to use a compressor to pump air at high pressure down into the well, to force the water out (essentially make the upward pressure higher than the atmosphere alone provides), or revert to the tried and true method using buckets.Of course, a similar principle applies with underground or artesian wells. The water there is already under greater pressure and will flow to the surface if given a path.
How many ounces in 1 cup water?
1 cup = 8 fluid ounces, regardless of what's in the cup. Even if it's empty.
Why does it take longer to heat a bucket of water than a cup of water?
Because there is more water in a bucket than in a cup, and more energy has to be put into the bucket of water than the little cup of water to bring them to the same temperature.
Why a cup crack when it is filled with boiling water?
When a cup is filled with boiling water, the heat from the water caused the material of the cup to experience thermal expansion. If the cup is badly made, then different parts of it will expand to different extents and this will create stresses in the material of the cup causing it to crack.
How does water get on the outside of a cup?
Water might disappear on a cup through evaporation. As the water sits, it begins to turn to a gaseous state and rises away from the cup.
What is difraction?
when something looks bent when you put a straw in a cup of water and it looks bent that is difraction
What happens to the straw placed in plastic cup full of water?
straw seems at above from the bottom and seems to be broken because water bent the rays of light as the light leaves the water it is bent or refracted from its usual straight line.
Why does a pencil appear bent in a cup of water?
This is due to apparent shift in the position of pencil when viewed from a rarer to denser medium. This is also on account of refraction of light.
What would happen if you put a straw in a cup of water?
uhm, nothing except the water would go into the straw. it really isn't that hard to figure out
Where is the first water item at club penguin 2010?
The cup with the straw at the stadium at the BIG concession stand:)
Is drinking out of a straw healthier for you?
No. It's the same as drinking right from the cup. Unless your out in the wilderness and you don't have clean water, you can get straws that filter your water.
Do you drink more when drinking through a straw?
I personally think you drink more when using a straw. I drink twice as much with a straw than tipping the cup.
Why does a pencil bend in a cup of water?
The pencil doesn't bend. The light, when it passes into or out of water, changes direction slightly. also it's refracted it looks bigger and bent but light changes the direction that's way it looks bent and bigger also our eyes see it differently.
How do you clean a crazy straw cup?
If you are talking about the kind that has a groove embedded in the side of the cup whether the straw goes, I removed the straw and soaked it in hot water with a tablespoon of bleach. If there is material, such as clotted milk, let it soak until the solids dissolve. The trouble is being sure that everything has rinsed out. I let hot water run through the straw for a few minutes and then blew on one end to make sure there was no water trapped inside. I wiped off the tip and let it dry in the strainer. The tricky part was getting it back on correctly. I wound up throwing it away when my three year old wasn't looking.
What is the most common type of paper cup lids?
straw-slot
How does the last amount of liquid in a straw get into your mouth when the cup is empty and there is no more surface liquid for atmospheric pressure to work on forcing the liquid up the straw?
Air pressure within the straw.
Why does a spoon in a cup of water looks bent and discontinuous when viewed through the side of the cup?
when the rays of light falls from the air to water, it bends away from normal,inside water, bends towards normal,when it comes out of water again it ends away from from normal,hence its all because of refraction of light. sabin
