Understanding Pascal's Law

Understanding Pascal's Law
Pascal's law is one of the laws in physics that deals with liquid substances and the forces at their disposal. Studying Physics is incomplete if you don't know the sound of Pascal's law.

The sound of Pascal's law is:
Pressure applied to a liquid in a container, will be forwarded in all directions and equal
Pascal law was discovered by Blaise Pascal, a French scientist who lived in 1623-1662). Basically Blaise Pascal was a philosopher and theologian, but his hobbies in mathematics and physics, especially projective geometry, led him to become a world-famous scientist of all time thanks to his discoveries in the field of fluid mechanics related to pressure and force known as Pascal's Law.

Pascal's Law Formula
Pascal's Law is formulated with the term Pa (Pascal), a derivative unit for pressure. In accordance with its sound, then Pascal's Law is formulated as follows:
F1 / F2 = Force on surfaces A or B (N)
A1 / A2 = Surface area A or B (m2)
D1 / D2 = Surface diameter A or B (m)
The most well-known application of pascal law is that of a hydraulic lifting device or widely known as a Hydraulic Jack. Any object that uses the term Hydraulic is usually an application of Pascal's law. For example, a hydraulic jack. Hydraulic jacks are often used for heavy lifting such as when having to change a car tire

History of Physics Concepts Discovered
Blaise Pascal (1623-1662) was born in Clermont Ferrand on 19 June 1623. In 1631 his family moved to Paris. Blaise Pascal is the son of Etienne Pascal, a scientist and mathematician born in Clermont. Etienne Pascal, also a royal adviser who was later appointed as president of the Court of Aids organization in the city of Clermont. Pascal's mother, Antoinette Bigure, died when Pascal was four years old shortly after giving him a younger sister, Jacqueline.
He has an older sister named, Gilberte. Pascal also conducted hydrodynamic and hydrostatic studies, the principles of hydraulic fluids. His inventions included hydraulic presses and syringes.
Age 18 years, his body is weak and paralysis of the upper limbs makes Pascal must stay in bed. You have to swallow enough food to stay alive, even though you always feel a headache. 24 years old, he and Jacqueline went to Paris for a medical examination with more sophisticated equipment. Apparently he was required to stay in the hospital. Nowadays many scientists come to visit those who are interested in the vacuum experiment that he is working on. Descartes came to discuss. End of the year, his physical health enabled him to continue working, testing the theory of emptiness.
He has an experimental replica in the form of a 31-inch (78.7 cm) tube filled with mercury that is positioned upside down in a mercury bowl. Pascal wanted to find out what power was keeping the mercury in the tube, and what filled the empty space at the top of the mercury tube. Does it contain: air? mercury vapor? nothingness?
At that time, most scientists thought that the free space saved by mercury was nothing more than a vacuum, and several events that were thought to be impossible by previous scientists were seen when the experiment was carried out. This is based on Ariestoteles thinking, that "creation" something that is "substance", whether visible or invisible, and "substance / substance" forever moving. Ariestoteles law is as follows: "Everything that moves, must be moved by something (Everything that is in motion must be moved by something)". Therefore scientists adhering to Ariestoteles stated, that the vacuum (suction power) is impossible. How can it be ? Then the evidence is shown:
The light passing through it is called "vacuum" in a glass tube.
Ariestoteles writes, everything moves, must be moved by something else. Therefore, there must be an invisible "something" to move the light through the glass tube, therefore there is no vacuum (suction or pressure) in the tube. Not in the glass tube or anywhere. Vacuum does not exist and something is impossible.
After conducting in-depth experiments on this vein, in 1647 Pascal issued a treatise on Experiences nouvelles touch video ("New Experiments with the Vacuum"), he explained in detail the basic rules, that the degree of variation of the liquid could be supported by air pressure. This gives a reason or proof, that there is indeed a vacuum in the column above the liquid barometer tube. And, Ariestoteles statement was broken by Pascal. Vacuum is there! Not something that is impossible. These evidences put Pascal in conflict with other scientists, especially the leading scientists before him, let alone the followers of Ariestoteles, including in conflict with Descartes.
Pascal's brain intelligence is beyond doubt, but from birth he is physically weak and vulnerable to illness. In 1661, his younger brother Jacqueline died. Pascal showed his condolences to his brother, Gilberte and to the sisters of Jacqueline's friends. One year later, Pascal's health condition worsened and refused all help that came or anything that could alleviate his illness.
He wants to die in the hospital - just like poor people (rich people always die at home), but that does not mean that is accomplished. On August 19, 1662, early morning, Pascal died after a long period of unconsciousness. The cause of Pascal's death is unknown. Some people call it because of tuberculosis; others call for metal poisoning or dyspepsia which weakens brain function. Pascal left the work entitled Pensees and Provincial Letters which had nothing to do with mathematics.

Pascal's Law Equation

Pascal's Law Equation
Pascal also wrote about hydrostatics, which explains his experiments using a barometer to explain his theory of the Equilibrium of Fluids, which was not published until a year after his death. His paper on the Liquid Body Equation prompted Simion Stevin to conduct an analysis of the hydrostatic paradox and to correct what is called the last law of hydrostatics:

"That liquid objects distribute compressive power equally in all directions"
which came to be known as Pascal's Law. Pascal's Law is considered important because of the relationship between the Liquid Body Theory and the Gas Body Theory, and about the Changes in Shape about the two which came to be known as the Hydrodynamic Theory. Pascal's Law (1658) "If a liquid is subjected to pressure, then that pressure will propagate in all directions without increasing or decreasing its strength". Pascal's Law states that the pressure exerted by liquid in a confined space is transmitted in all directions equally.
Every point at the same depth has the same amount of pressure. This applies to all liquid substances in any container and does not depend on the shape of the container. If external pressure is added, for example by pressing the surface of the liquid, the pressure increase in the liquid is the same in all directions. So, if given external pressure, every part of liquid gets the same pressure allotment (Lohat, 2008).
In accordance with Pascal's law that the pressure exerted on liquid in a confined space will be transmitted equally in all directions, then the pressure entering the first inhaler is equal to the pressure in the second inhaler (Kanginan, 2007).
Pressure in fluid can be formulated by the equation below.
P = F: A
so that Pascal's law equation can be written as follows.
P1 = P2
F1: A1 = F2: A2
Where: P = pressure (pascal),
  F = style (newton),
A = surface area of cross-section (m2).
From Pascal's law it is known that by applying a small force on a vacuum with a small cross-sectional area can produce a large force on a vacuum with a large cross-sectional area (Kanginan, 2007). This principle is utilized in technical equipment that is widely used by humans in life such as hydraulic jacks, hydraulic pumps, and hydraulic brakes (Azizah & Rokhim, 2007).

Principles of Application of Pascal's Law
The Working Principle of Hydraulic Jacks
The working principle of a hydraulic jack is to utilize Pascal's law. Hydraulic jacks consist of two related tubes which have diameters of different sizes. Each is closed and filled with water. The car is placed on the lid of a large diameter tube. If we apply a small force to a tube with a small diameter, the pressure will be spread evenly in all directions including to the large tube where the car is placed (Anonymous, 2009a). If the F1 force is applied to a small suction, the pressure in the liquid will increase with F1 / A1. The upward force exerted by the liquid on the larger suction is this increase in pressure times the area of A2.
If this force is called F2, it is obtained
F2 = (F: A1) x A2
If A2 is much larger than A1, a smaller force (F1) can be used to produce a much larger force (F2) to lift a load placed in a larger suction (Tipler, 1998).
The following is an example of calculating the pressure on a hydraulic jack. For example, a hydraulic jack has two sockets with a cross-sectional area A1 = 5.0 cm2 and a cross-sectional area A2 = 200 cm2. When given an F1 force of 200 newtons, the suction with an A2 cross-sectional area will produce a force F2 = (F1: A1) x A2 = (200: 5) x 200 = 8000 newtons.

Hydraulic Brake Principles Work
The basis of braking work is the use of friction and Pascal's law. The vehicle's motion force will be resisted by this friction force so that the vehicle can stop (Triyanto, 2009). Hydraulic brakes are most widely used in passenger cars and light trucks. Hydraulic brakes using the principle of Pascal's law with pressure on a small piston will be forwarded to a large piston that holds the disc.
Any liquid in the piston can be replaced. Hydraulic brakes are commonly used in brake fluid because the oil can also function to lubricate the piston so that it does not jam (immediately return to its original position if the brake is released). If water is used, it is feared that rusting will occur (Anonymous, 2009).

Hydraulic Brake Principles Work
Hydraulic Pump Operating Principle
In running a particular system or to assist the operation of a system, we often use a hydraulic circuit. For example, to lift a series of containers that have loads of thousands of tons, to facilitate that use a hydraulic system.
Hydraulic system is a technology that utilizes a liquid, usually oil, to make a line of movement or rotation. This system works according to Pascal's principle, that is, if a liquid is subjected to pressure, that pressure will propagate in all directions without increasing or decreasing its strength. The principle in a hydraulic circuit is to use a working fluid in the form of a liquid that is moved by a hydraulic pump to run a particular system (Anonymous, 2009).
The hydraulic pump uses the kinetic energy of the liquid pumped in a column and the energy is given a sudden blow into another form of energy (compressed energy). This pump serves to transfer mechanical energy into hydraulic energy. The hydraulic pump works by sucking oil from the hydraulic tank and pushing it into the hydraulic system in the form of flow (flow). This flow is exploited by turning it into pressure. Pressure is generated by blocking the flow of oil in the hydraulic system.
These obstacles can be caused by orifice, cylinders, hydraulic motors, and actuators. Hydraulic pumps are commonly used there are two types of positive and nonpositive displacement pump (Aziz, 2009). There are two types of equipment that are usually used in converting hydraulic energy into mechanical energy, namely hydraulic motors and actuators. Hydraulic motors transfer hydraulic energy into mechanical energy by utilizing the oil flow in the system to convert it into rotational energy which is used to drive wheels, transmissions, pumps and others (Sanjaya, 2008).

Benefits or Uses of Polymers in Everyday Life

Benefits or Uses of Polymers in Everyday Life
Uses of Polymers
For Polyethylenterephthal Plastic (PET)
For Polyethylene / Polyethylene (PE) Plastics
For Polyvinyl Chloride (PVC)
For Nylon Plastics
For Synthetic Rubber
For Wol
For cotton
Polyethylentereftalat Plastic (PET)
PET plastic is a synthetic polyester fiber (dacron) that is transparent with strong durability, resistant to acids, airtight, flexible, and not brittle. In terms of use, PET plastic ranks first. It uses around 72% as a beverage packaging with good quality. PET plastic is polyester that can be mixed with natural polymers such as silk, wool and cotton to produce clothing that is durable and easy to care for.

Polyethylene / Polyethylene (PE) Plastics
There are two types of PE plastic, namely Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE). LDPE plastic is widely used as a plastic bag and wrapping food and goods. HDPE plastic is widely used as a base for making children's toys, strong pipes, gas lighters, radio and television bodies, and vinyl records.

Polyvinyl Chloride (PVC)
PVC plastic is thermoplastic with strong durability. This plastic is also resistant and impervious to oil and organic materials. There are two types of PVC plastic which are rigid and flexible. Rigid plastic forms are used for building construction, children's toys, PVC pipes (paralon), tables, cabinets, vinyl records, and some car components.
As for the flexible form plastic, this type is used to make plastic hoses and electrical insulation. In terms of use, PVC plastic ranks third and around 68% is used for building construction (water pipes).

Nylon Plastic
Nylon plastic is a polyamide polymer (the process of formation such as protein formation). Nylon plastic was discovered in 1934 by Wallace Carothers of the Du Pont Company. At that time, Carothers reacted adipic acid and hexamethylenediamine. Plastic that is very strong (not easily damaged) and smooth is widely used for clothing, camping and rock climbing equipment, household equipment and laboratory equipment.

Synthetic Rubber
The famous synthetic rubber is Styrene Butadiene Rubber (SBR), a polymer formed from the polymerization reaction between styrene and 1,3-butadiene. Synthetic rubber is widely used to make vehicle tires because it has good strength and does not expand when exposed to oil or gasoline.

Wool is a natural fiber from animal protein (keratin) which is insoluble. The flexible structure of wool protein produces good quality fabric, but sometimes causes problems because it can shrink in washing. Therefore, wool is mixed with PET to produce a good quality fabric and does not shrink during washing.

Cotton is a natural fiber from vegetable materials (cellulose) which is the most widely used (almost 50% use of natural fiber comes from cotton). Cotton fabric is made from cotton fibers with chemical treatment so as to produce a fabric that is strong, comfortable to wear, and easy to care for.

Polymer Classification Based on Heat

Polymer Classification Based on Heat
Based on its nature to heat, polymers can be distinguished from thermoplastic polymers (non-heat resistant, such as plastics) and thermostopped polymers (heat resistant, such as melamine).

Thermoplastic polymer
Thermoplast polymers are heat-resistant polymers. When the polymer is heated it will melt (soften), and can be melted to be reprinted (recycled). For example polyethylene, polypropylene, and PVC.

Polymer posted
Posting polymers are heat-resistant polymers. The polymer when heated will not melt (difficult to soften), and difficult to recycle. For example melamine and bakelite.

Examples of Artificial Polymers
In everyday life, we certainly use a lot of artificial polymers. Here are some examples of artificial polymers around us:

Synthetic Rubber
With the increasing need for car and motorcycle tires, organic chemists have developed the manufacture of synthetic rubber to accelerate the acquisition of these needs. Synthetic rubbers are made using monomer-based materials, such as butadiene and styrene by copolymerization.

Synthetic Fiber
Cotton is a natural fiber which is a polymer from carbohydrates (cellulose), and a polymer from protein (wool and silk). Like rubber, fiber has synthetic polymers, namely nylon and polyester (dacron). Dakron or tetoron is polyester. This polymer is very strong, very flexible and transparent.

Orlon is an addition polymer of an acrylonitrile monomer. This polymer is a synthetic fiber, like wool used in textiles as a mixture of wool, carpet, and socks.

Plastic is the most popular synthetic polymer because it is widely used in everyday life. Based on the type of monomer, there are several types of plastic, namely as follows:

Polyethene (Polyethylene)
Polyethylene is a plastic polymer that is resilient (clay), low density, flexible, difficult to damage if long exposed in the air or when exposed to mud, but can not stand the heat. Polyethene is a plastic that is widely produced, printed sheets for plastic bags, yard wrapping, buckets, etc.

Polypropene (Polypropylene)
Polypropene has the same properties as polyethene. Because this plastic is also widely produced, only its strength is greater than polyethene and is more resistant to heat and resistant to acid and base reactions. This plastic is also used to make plastic bottles, sacks, water tanks, ropes, and electric canisters (insulators).

PVC (Polyvinyl Chloride)
PVC has hard and rigid properties used to make plastic pipes, plastic pipes, electrical cable pipes, synthetic leather, and plastic tiles.

Teflon (Tetrafluoroetene)
Teflon is a thin layer that is very resistant to heat and resistant to chemicals. Teflon is used for pan coatings (nonstick panic), tank coatings in chemical plants, broken pipes, and electrical cables.

Bakelit (Phenol Formaldehyde)
Bakelite is a type of polymer made from two types of monomers, namely phenol and formaldehyde. This polymer is very hard, its melting point is very high and it is fire resistant. Bakelite is used for electrical installations and tools that can withstand high temperatures, such as ashtrays and electric light fittings.

Flexiglass (Polymethyl Methacrylate)
Polymethyl Methacrylate abbreviated as PMMA has the trade name Flexiglass. Polymethyl methacrylate is the addition polymerization of the methyl methacrylate monomer (H2C = CH-COOH3). PMMA is a strong and transparent plastic. This polymer is used for aircraft windows and car taillights.

Example of the Formation of Polyethene from Ethene

Example of the Formation of Polyethene from Ethene
Here are some examples of their formation:
In the formation of polyisoprene, the two double bonds of number 1 and C number 3 first open, then the single bonds of C number 2 and C number 3 form the double bonds. From the examples of the reaction above, it can be concluded that in addition addition polymerization the byproducts are formed and the monomers must contain double bonds. Examples of addition polymers can be seen in the table below.

Polymer Monomers Polymer name
Polyethylene Plastic bags, bottles, toys, electrical insulation
Polypropylene Plastic rugs, bottles
Polystyrene Wood varnish, styrofoam, plastic insulation, plastic cups, toys, packing material
Polyvinyl chloride Pipe, plastic tile
Polyvinyl dienkloride Plastic wrap
Politetraethylene (Teflon) Cookware, electrical insulation (cable cover)
Polyacrylonitrile Wigs (toupee), paint, thread
Polyvinylacetate Textile, gumresin, paint
Polymetilmetakrilat Glass making material, bowling ball maker
Condensation Polymers

Condensation is the reaction of combining functional groups between the two monomers. That is, condensation polymerization is the reaction of polymer formation from monomers having two functional groups. For example, polypeptide compounds or proteins and polysaccharides are biomolecular compounds formed by condensation polymerization reactions.

Condensation polymerization will produce small molecules of water and the monomers have functional groups at both ends of the chain. If formulated, the general reaction is as follows:
n monomers → 1 polymer + (n - 1) H2O

Here are some examples of the formation of condensation polymerization:
The formation of nylon
Nylon is a polymer that was discovered by Wallace Hume Carothers in 1934 while working at the Du Pont company. Nylon polymers are formed from 6-aminohexanoic acid (HOOCCH2 (CH2) 3CH2NH2) monomers. In this polymerization, the carboxyl group of the monomer binds to the amino group of the monomer.

Formation of polyester (polyethylene terephthalate) or dacron
Similar to nylon-66, polyester dacron is formed by 2 different polymers, namely from ethylene glycol (polyalkohol) with dimethyl terephthalate (ester compound).

Polymer Classification Based on Type of Monomer
Based on the type of monomer, polymers can consist of homopolymers and copolymers.

Homopolymers are polymers with similar monomers. For example, cellulose and protein.
(-P-P-P-P-P-P-P-P-) n
In homopolymer addition polymers, the double bonds open then bind to form a single bonded polymer.

Copolymers or also called heteropolymers are polymers whose monomers are not the same type. Examples of dacron, nylon-66, melamine (phenol formaldehyde). The process of polymer formation takes place with high temperature and pressure or assisted with a catalyst, but without the catalyst the molecular structure is formed irregularly.
Thus, the function of the catalyst is to control the formation process of polymer molecular stricture to be more orderly so that the properties of the polymer obtained are as expected. Examples of the molecular chain structures of irregular polymer 9) polymerization products without catalysts are as follows:

(-P-S-S-P-P-S-S-S-P-S-P-) n
Irregular copolymers
In the process of forming the polymer used by the catalyst, the molecular structure formed will be regular. Examples of regular polymer molecular chain structures (polymerization products with catalysts) are as follows:

Block system:
(-P-P-P-S-S-S-P-P-P-S-S-S-) n
Block copolymer alternating system:
(-P-S-P-S-P-S-P-S-P-S-P-S-P-) n
Copolymers alternate

Polymer Classification Based on Origin

Polymer Classification Based on Origin
Based on its origin, polymers can be distinguished from natural and synthetic polymers.

Natural Polymers
Natural polymers are polymers found in nature and come from living things. Examples of natural polymers can be seen in the table below
No. Polymer Monomer Polymerization Example
1. Starch / starch Glucose Condensation Grains, root roots
2. Glucose Cellulose Vegetable, Wood, Cotton Condensation
3. Protein amino acids Condensation for Milk, meat, eggs, wool, silk
4. Nucleotic Acid Condensation of DNA and RNA (cell) Molecules
5. Natural rubber Isoprene Rubber tree sap addition
The properties of natural polymers are less favorable. For example, natural rubber is sometimes easily damaged, not elastic, and choppy. This can occur because natural rubber is not resistant to petrol or kerosene oil and has long been open in the air.
Another example, silk and wool are bacterial protein compounds, so wool and silk are easily damaged. Generally natural polymers have hydrophilic (water-like) properties, are difficult to melt and are difficult to print, so it is very difficult to develop the function of natural polymers for broader purposes in people's daily lives.

Polymer Synthesis
Synthetic polymer or artificial polymer is a polymer that is not found in nature and must be made by humans. Until now, polymer chemists have been conducting natural molecular structure research to develop their synthesis polymers. From the results of these studies produced synthetic polymers that can be designed for its properties, such as high and low melting points, flexibility and hardness, as well as resistance to chemicals. The goal is to obtain a synthetic polymer which is used as expected.
Synthesis polymers that have been developed for commercial purposes, for example the formation of fibers for fabric threads and the production of elastic tires against highways. Today chemists have succeeded in developing hundreds of types of synthetic polymers for broader purposes. Examples of synthetic polymers can be seen in the table below:
No Polymer Monomers Available at
1. Polyethene Ethene Pouches, plastic cables
2. Polypropene Propena Ropes, sacks, plastic bottles
3. PVC Vinyl chloride Paralon pipe, floor coating
4. Polyvinyl alcohol Vinyl alcohol Tub of water
5. Teflon Tetrafluoroetene Non-stick skillet or pan
6. Dacron Methyl terephthalate and ethylene glycol Magnetic record pipe, fabric or textile (synthetic wool)
7. Adipic and hexamethylene diamin acid Nylon Textiles
8. Polybutadiene Butadiena Motorcycle tires
9. Polyester Esters and Ethylene Glycol Car Tires
10. Melamine Phenol formaldehyde Plate and melamine glass
11. Epoxy resin benzene methoxy and secondary alcohol paint coating (epoxy paint)
Polymer Classification Based on the Process Formation
The polymer formation reaction is called polymerization, so the polymerization reaction is the reaction of combining small molecules (monomers) to form large molecules (polymers). There are two types of polymerization, namely addition polymerization and condensation polymerization.

Addition polymer
As we have already seen, that addition reaction is a reaction of breaking double bonds into a single bond so that there are atoms that are added in the compound that is formed. Thus, addition polymerization is the reaction of the formation of polymers from double bonded monomers (unsaturated bonds). In this reaction the monomers open their double bonds and then bind with other monomers to produce a single bonded polymer (saturated bond).
That is, the addition polymer monomers that form additives are carbon-bound double bond compounds such as alkenes, sterines, and haloalkenes. This addition polymer is usually identical to plastic, because almost all plastics are made by addition polymerization. For example polyethene, polypropene, polyvinyl chloride, teflon and polyisoprene.

Three-Dimensional Tissue Polymer

Three-Dimensional Tissue Polymer
Polymeric Properties
Polymers are macromolecules which consist of many classes of natural and synthetic materials with very diverse properties. The difference between the two materials lies in whether or not a polymer is degraded or overhauled by microbes. Usually, synthetic polymers are more difficult to decompose by microorganisms than natural polymer materials. The difference in the properties of the polymer is influenced by the structure of the polymer, which includes:

1. The length of the polymer chain
The longer the polymer chain, the higher the strength and melting point of the compound.

2. Intermolecular force
The greater the intermolecular force in the polymer chain, the polymer will be strong and difficult to melt.

3. Branching
The multi-branched polymer chain has low tensile strength and melts easily.

4. Cross-linking between polymer chains
The more cross-linking, the more rigid and brittle the polymer so that it is easily broken. That is because the presence of cross-linkages between polymer chains results in rigid tissue forming and forming hard materials.

5. The crystallinity properties of the polymer chain
The higher the crystallinity, the polymer chain will be stronger and more resistant to chemicals and enzymes. Usually the high crystallinity is polymers with regular structure, whereas polymers with irregular structure tend to have low crystallinity and are amorphous (not hard).

General Properties of Polymers
1. Thermal Properties
Polymers as insulators have good thermal properties even though polymers are not conductors. When viewed from its type, some polymers that are heated become soft but some pulses become hard. This change is important for certain component materials.

2. Flexibility
Because it is flexible, polymers are easily processed into desired products. But, natural polymers are more to be processed as desired than synthetic polymers.

3. Nature of Resistance to Microorganisms
The nature of resistance to these microorganisms is usually owned by synthetic polymers. While natural polymers such as silk, wool, and other natural polymers are not resistant to microorganisms.

4. Other Properties
Other properties possessed by polymers include the following:
Light, in the sense of a small weight / volume ratio;
Resists corrosion and damage to aggressive environments;
Its dimensions are stable because it has a large molecular weight; and others.
Polymers that have cross-bonds will be thermosetting, while polymers that do not have cross-bonds will be thermoplastic.
Thermosetting is a type of polymer that remains hard and cannot be soft when subjected to heat. This polymer can only be heated once, at the time of manufacture. So if after a break can not be reconnected. An example of this type of polymer is Bakelite.
Thermoplastic is a type of polymer that can be softened when it is hot and hardened again after being cooled. This means that this type of polymer can be heated repeatedly. Examples of polymers that enter this type are types of plastics such as polyethylene PE, PP polyproylene plastics, polyethylene terephthalate plastics, and polyvinyl chloride PVC plastics.