Why do pencils float?

Why do pencils float?

The pencil falls below the water's surface in the saline water. In the salt water, more of the pencil is submerged than previously. More of the pencil is visible above the water in the salt water than previously. This makes a less dense mass of wood and graphite that floats.

There are two reasons why pencils will always be floating: first, their wood is mostly cellulose (75%), so it is a heavy material for its size; second, they contain some amount of oil that prevents them from drying out and making them sink.

Cellulose is the main component of paper too. When paper gets wet, the cellulose fibers expand and let more water inside, similar to how glass expands when it gets wet. This expansion causes the paper to get heavier. Paper weights vary depending on what kind of fiber is used but the average weight of a sheet is about 30 grams per square meter (gsm). That's about as much weight as the pencil I'm holding in my hand right now!

When paper gets wet, there are two ways for it to dry: either air-dry or water-proof-coat-dry. An air-dry paper will lose its weight and become very brittle after a few weeks if it isn't stored in a dry place.

Is the pencil floating in the water?

Examine the pencil in the water. Examine the lettering on the side of the pencil, as seen in image A. The pencil would float higher than before the additional salt was introduced. The pencil would float at the same level as before the additional salt was applied. In other words, there is no evidence to suggest that the pencil is or is not floating in the water.

In conclusion, because the pencil appears to be floating in the water, it can be inferred that it is a non-toxic lead pencil. Any other type of pencil would have been removed from the pool by now if they were toxic.

What happens when a pencil is immersed in water?

When a pencil is partially immersed in water, it seems to bend on the water's surface as a result of light refraction at the air-water interface. A beam of light from the bottom end is refracted away from the normal as it passes through the water in the air. Therefore, the pencil appears to be bent.

When fully immersed in water, the weight of the pencil pulls it down to the bottom so that it no longer rises above the surface. The beam of light coming up from below now encounters no material between it and the top of the pencil. So there is no more reflection and the pencil appears to be lost beneath the water surface.

Reflection comes from molecules that are fixed in place by chemical bonds. These molecules are always aligned in the same way, so when an incident light ray hits one side of them they all reflect that light ray back in the direction it came from. For visible light this means that objects that are solid and flat will appear white or grey depending on their color, and objects that are hollow will appear black. Anything transparent or semi-transparent will show through.

Water is made up of hydrogen atoms connected together with single bonds. Each oxygen atom is connected to two hydrogen atoms with double bonds forming covalent bonds. When light falls on a molecule it can break these bonds creating particles called photons.

Why does a pencil dipped in water appear bent at the surface of water class 8?

Due to light refraction, a pencil dipped in water looks twisted at the interface between air and water. Light refraction happens when the speed of light varies as it passes from one medium to another. In this case, the speed of light in water is less than that in air so it bends away from the axis of the pencil.

Reflection also causes problems for anyone trying to draw accurately. If you were to dip your pencil into water and then use it to draw a line on wet paper, the line would not be straight; rather, it would be bent towards the direction it was drawn from.

The reason for this is simple geometry: if you are drawing an object with a flat bottom such as a stick or a knife, any liquid that gets on the tool will cause it to rise up out of the water body. Since sticks and knives are usually not perfectly vertical, they will appear bent near the surface of the water.

This effect can be used by artists to create realism in their drawings. For example, if you were to dip your pencil into water and draw a fish on a piece of paper, the fish would look three-dimensional because of the reflection.

You can see this effect being used in action in the video below.

Why do pencils bend in water?

Light moves from water to air when you look at the section of the pencil that was immersed in water (or from water to glass to air). This light beam alters the medium and is subsequently refracted. As a consequence, the pencil picture looks to be shattered.

Pencil lead is made up of very small particles called graphite. When these particles are exposed to air they quickly lose their microscopic dimensions and become dusty. To keep their shape, when lead pencils are not being used they are wrapped in plastic or placed in cardboard boxes. When lead pencils are moved or knocked around too much their fragile structure can be damaged, which causes them to break off easily. This leads to all sorts of problems: some bits of pencil may not be broken off completely which can cause difficulties when trying to write with a blunt pen.

When you look at a piece of paper it is the ink on the paper that reflects light, not the paper itself. The only way for you to see the actual pattern of the paper is if there is any white space between the lines or letters. Otherwise, everything would run together and look like one big blob. Most paper has an oily coating which helps it to reflect light; this is why papers feel soft to the touch. Graphite will stick to this coating, creating a drawing when you use a hard pencil.

About Article Author

Peter Perry

Peter Perry is a writer, editor, and teacher. His work includes books, articles, blog posts, and scripts for television, and film. He has a master's degree in Writing from Emerson College.


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