Explain The Properties Of Water Cohesion

Water is a medium for metabolic reactions and an important constituent of cells. In most plants and animals, it makes up about 65-95% of their mass. The water molecule is referred to as a dipole, a polar molecule, with a positive (hydrogen) and negative (oxygen) charge, separated by a very small distance. A molecule with a separated charge is polar. A hydrogen bond; the weak attractive force between a hydrogen atom with a partial positive (o+) charge and an atom with a partial negative charge (o-) oxygen can be formed between two atoms. Hydrogen bonds are weak, however in large quantities, like the large number present in water it makes the molecules difficult to separate and gives water a wide range of physical properties vital to life.

The purpose of this experiment was to see if a penny could hold more drops of salt water or tap water. It was found that a penny could hold an average of 22.3 drops of tap water and only 20.8 drops of salt water. These results are consistent with the hypothesis: If the salt concentration of water impacts the amount of water a penny holds, then the penny will hold less drops with salt water. While dropping the water onto the penny, it was observed that the water formed into a dome-like shape on the penny. It looked like the individual drops of water turned into one large drop of water. This was observed for both the tap and salt water. This happened due to the cohesion and surface tension of water. Cohesion simply means that water molecules are attracted to each other and want to cling together. Surface tension is the special term that is applied to the cohesion of water molecules.

The hydrogen bonds that are formed between liquid water molecules are so strong that they can absorb tremendous amounts of heat energy when breaking. These hydrogen bonds breaking prevent large temperature increases from occurring instantly. A couple benefits include preventing car engines from overheating and maintaining the human body’s temperature. Since the body is mostly

Attraction between water molecules which allows insects and other objects to float a top the water

When an object falls onto the surface, it has to push the water molecules apart. If the effect of the weight of the object is insufficient to match the attractive forces between molecules in the surface layer, the object will not enter the surface.

The response earned 1 point for providing a role of water in temperature regulation when it describes how

What special bond (in water) opposes water’s molecular movement when water absorbs energy requiring water to have more heat added to raise its temperature? Hydrogen Bond.

If a pillbug is exposed to water, then it will be attracted to the water.

Clumps together, ability to keep water in its shell and release it as needed to stay moist

(Click Slide) Another unique property of water is its high specific heat capacity. Due to the strong hydrogen bonds that exist between water molecules, a lot of energy is needed to break down the bonds. As the Particle Theory states, particles move faster and further apart when heated. This is why water helps maintains a moderate temperature on Earth and different bodies of water, crucial for the survival of organisms.

There are four basic components for thermal energy (heat): 1. All matter is made up of tiny particles called atoms. These can only be seen with special microscopes. 2. The atoms are always moving – they all have kinetic energy. 3. The particles have space between them. Different states of matter have different amounts of space. 4. Adding heat (energy) to matter makes the particles move more quickly. Since faster moving things have more kinetic energy, adding heat increases the energy of the particle. 5. Cooling it down decreases the amount of kinetic energy and slows the movement down.

A water molecule is able to interact with up to four other water molecules to create a tetrahedral. The second part of the lab, we will be observing cohesion and adhesion theories. Cohesion is when water molecules stick to each other and adhesion is the occurrence of water molecules sticking to other molecules. To observe adhesion and cohesion, we will pipette a drop of water on a piece of parafilm; we will be looking for if they water will be stuck together or did it spread apart, we will be explaining our observations. We will then, repeat the same experiment, however instead of parafilm we will use a glass slide; we will try to compare cohesion between the water molecules and the adhesion between the water and glass slide. After, we are done pipetting the water and observing, we will then demonstrate what happened in the pipette part (both the parafilm and the glass slide) of the experiment using the 12 water molecules and the non-magnetic tray. The third part of the experiment consists of testing

Earth is a perfect distance from the sun so the temperature of the Earth is the right tempeture for water.

The key feature is that heat is transferred from the skin at 37.5 °C to the water at 23.5 °C. Vapourization requires that heat be absorbed by the water:

When heat is added to a substance, the kinetic energy of individual particles increases, which makes them move faster resulting in a increase in temperature. The more heat that is added per gram of substance, the greater the temperature change. The relationship between the heat added, the mass of a substance, and the temperature change it undergoes is known as the specific heat.