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# Difference between Scientific terms

Difference between different biological and physical terms with examples.

 Scalars Vectors Quantities which have magnitude only, and no direction are called Scalars.For example, Speed, Temperature, Mass etc. Quantities which have a direction as well as a magnitude are called Vectors.For example, Velocity, Weight, Force etc. Speed Velocity Rate of change of distance is called Speed. For example, This car can travel with speed 80m/s. Speed can be calculated as: Speed = Distance / Time Velocity means the speed of something and its direction of travel.For example, A car is moving with velocity 80m/s towards East. Heat Temperature Heat is the energy an object has because of the movement of its atoms and molecules. Heat depends on the size or type of object.For example, A 1000 watt light bulb will give off more heat as compare to 100 watt light bulb. Temperature is not energy, but a measure of it. Temperature does not depend on the size or type of object.For example, the temperature of a small cup of boiling water is the same as the temperature of a large pot of boiling water. Periscope / Telemeter Perimeter Periscope:A Periscope is a scientific instrument for observation from a concealed position.Telemeter:A Telemeter is a scientific instrument for measuring distance from observer. A perimeter is the length of boundaries or outer lines of an object. For example,` `The perimeter of this rectangle is:Perimeter = 4 + 4 + 2 + 2 = 12 inches Microscope Telescope Microscope is a scientific instrument for magnifying small objects. Telescope is a scientific instrument for viewing objects at great distances. Element Molecule An Element is a single substance which cannot be split into two or more simpler substances by chemical means. A Molecule is the smallest particle of a compond. Molecules are made up of two or more atoms. Mixture Compound When two or more atoms or molecules combine together, they form Mixture.For example, Alloys are mixture of two or more metals, so they contain two or more different types of atoms.Other Differences:1. It can be separated by physical means.2. Its physical properties are intermediate between those of the substances in it.3. A mixture's composition can vary.4. Its chemical properties are the result of the substances in the mixture. When two or more elements chemically combine together, they form Compounds. Compounds are pure substances as they contain only one type of molecules, e.g. Water, Carbon dioxide.Other Differences:1. It cannot be separated by physical means.2. Its physical properties are individual and not the result of its elements.3. A compound's composition cannot vary.4. Its chemical properties are quite different from those of its elements. Atomic Number Mass Number The atomic number of an element is the number of protons or electrons in its atom. The mass number of an element is the total number of protons and neutron in its atom. Isotopes Isomers Isotopes are atoms of the same element with different numbers of neutrons. As they contain same number of protons or electrons, so chemically they are identical. But, as they have different number of neutrons, so they have different masses.For example, Deuterium is isotopes of Hydrogen. Both have same atomic number (1). But different mass number: Hydrogen = 1; Deuterium = 2 Molecules with identical molecular formulae but with different structural formulae are called Isomers.For example,Butane and Isobutane are isomers because they have same molecular formulae, but different structure.As they have different structures, so they have different physical properties. And, as they have identical molecular formulae, so they react in a similar way. Reversible Reaction Irreversible Reaction A chemical reaction that can proceed in both directions; from reactants to products, and from products to reactants, is called Reversible Reaction. A chemical reaction that can proceed in one direction only; from reactants to products, and NOT from products to reactants, is called Irreversible Reaction. Endothermic Reaction Exothermic Reaction A chemical reaction which takes in energy (heat) and involves bond breaking is called Endothermic Reaction. A chemical reaction which gives out energy (heat) and involves bond making is called Exothermic Reaction. Oxidation Reduction Oxidation is a/an:gain of oxygenloss of hydrogenloss of electronincrease in oxidation state Reduction is a:loss of oxygengain of hydrogengain of electrondecease in oxidation state Anode Cathode The anode is the electrode connected to the positive terminal of a cell (battery). The cathode is the electrode connected to the negative terminal of a cell (battery).