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Atal Tinkering Labs ATL

Laws of Reflection of Sound

Reflection is the change in direction of a wave front at an interface between two different media so that the wave front returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. When sound travels in a given medium, it strikes the surface of another medium and bounces back in some other direction, this phenomenon is called the reflection of sound. The waves are called the incident and reflected sound waves.   This video explains how to verify the laws of reflection of sound.  

Properties of Acetic Acid

Acetic acid is an organic acid with the formula CH3-COOH. Its functional group is carboxylic acid group. Acetic acid is a monocarboxylic acid because it contains only one COOH group. It has a sour taste and pungent smell. It is the main component of vinegar. Vinegar is typically 3-7% solution of acetic acid in water. Vinegar is mainly used as a preservative in food and in the pickling of vegetables. The water free acetic acid is known as glacial acetic acid.   This video explains how to study the following properties of acetic acid (ethanoic acid): (a) Odour, (b) Solubility…

Embryo of Dicot Seeds

A seed is a small embryonic plant enclosed inside a seed coat. It is the ripened and fertilised ovule of gymnospermic and angiospermic plants. The embryo is an undeveloped plant inside a seed from which a new plant develops. All seeds do not have the same size, shape and colour. Plant embryos in seeds have structures called cotyledons. A cotyledon is the central portion of a seed embryo to which the epicotyls- the immature shoot, and the radicle- the immature roots, are attached. Plants are classified according to the number of cotyledons present in the embryo. If the embryo has…

Qualitative Analysis of Carbohydrates

Carbohydrates are most abundant organic compounds found in living organisms and are composed of carbon, hydrogen and oxygen. Carbohydrates act as the primary source to provide energy for functioning of living organisms. These are called carbohydrates because they can be considered as hydrates of carbon. Generally carbohydrates are defined as polyhydroxy aldehydes or polyhydroxy ketones or the compounds which produces such products on hydrolysis. Carbohydrates are called saccharides. Some of them have sweet taste and are called sugars.   This video explains some simple tests of carbohydrates.  

Plant and Animal Tissues

A group of cells having common origin, similar structure and performing a definite function is called a tissue. Tissues are found in plants and animals. Plant tissues can be grouped into two basic types: meristematic and permanent tissues. Parenchyma and Sclerenchyma are permanent tissues. Animal tissues can be grouped into four basic types: epithelial, muscular, connective and nervous tissues. Different tissues have distinctive architecture best suited for what they do.   This video describes how to identify Plant tissues (parenchyma and sclerenchyma) and Animal tissues (striated (striped) muscle fibres and nerve cells) from the prepared slides.  

Cleaning Capacity of Soap

Ordinary water does not remove dirt from clothes or skin because the dirt present is oily or greasy in nature. Soaps are one of the most commonly used cleansing agents and are capable of reacting with water to remove dirt. Each soap molecule has a polar head group (carboxylate ion, COO- group) and a long non-polar hydrocarbon tail (R group from long chain fatty acid). The polar head attracts the polar water molecule and is called hydrophilic end and the non-polar tail attracts the water insoluble oily or greasy dirt particles. When a dirty cloth is placed in soap solution,…

Burning of Magnesium in Air

Magnesium is an alkaline earth metal with symbol Mg. It is a silvery white metal. It is a highly inflammable metal and is easy to ignite its powdered form or thin strips. Magnesium burns in air by taking oxygen from air to form magnesium oxide which is basic in nature.   This video explains the chemical change occurs during the burning of magnesium in air.  

Preparation of Pure Sample of Ferrous Ammonium Sulphate

Ferrous ammonium sulphate is a double salt of ferrous sulphate and ammonium sulphate. It has the formula FeSO4.(NH4)2SO4.6H2O. It contains two different cations Fe2+ and NH4+. It is prepared by dissolving an equimolar mixture of hydrated ferrous sulphate and ammonium sulphate in water containing a little of sulphuric acid, and then subjecting the resulting solution to crystallization when pale green crystals of ferrous ammonium sulphate separate out.   This video explains how to prepare pure sample of ferrous ammonium sulphate (Mohr’s salt).  

Surface Tension

Surface tension is the property of a liquid, by virtue of which its free surface at rest behaves like an elastic skin or a stretched rubber membrane, with a tendency to contract so as to occupy minimum surface area. This property is caused by cohesion of molecules and is responsible for much of the behaviors of liquids. Surface tension has been well- explained by the molecular theory of matter. According to this theory, cohesive forces among liquid molecules are responsible for the phenomenon of surface tension. The molecules well inside the liquid are attracted equally in all directions by the…

Preparation of Pure Sample of Potash Alum

Potash alum is a double salt of potassium sulphate and aluminium sulphate. It has the formula K2SO4.Al2(SO4)3.24H2O. It is prepared by dissolving an equimolar mixture of hydrated aluminium sulphate and potassium sulphate in minimum amount of water containing a little of sulphuric acid and subjecting the resulting solution to crystallization, when octahedral crystals of potash alum separate out.   This video explains how to prepare a pure sample of potash alum.  

Tests for Aldehyde

Aldehydes are organic compounds containing formyl functional group, in which the carbonyl carbon is attached to a hydrogen atom and an R group. The R group may be an alkyl or aryl group. Aldehydes are formed by replacing hydrogen atom of a hydrocarbon by the formyl group. The flavours of Almond, vanilla beans and cinnamon are due to the presence of aldehyeds.   This video explains how to identify aldehydes using some simple tests.  

Determination of Density of Solid

All matter has mass and volume. These are the physical properties of matter and may vary with different objects. The amount of matter contained in an object is called its mass and the amount of space occupied by the object is called its volume. So, the mass of a unit volume of a substance is called its density.   This video explains how to determine the density of a solid (which is denser than water) by using a spring balance and a measuring cylinder.  

Reaction of Zinc with Dilute Sulphuric Acid

Zinc is more reactive than hydrogen and it displaces hydrogen from dilute acids. Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas is evolved. Since the products zinc sulphate and hydrogen gas are entirely different in chemical composition and chemical properties from the reactants, the reaction is a chemical change.   This video explains the chemical change occurs during the reaction of zinc with dil. sulphuric acid.  

Tests for Carboxylic Acids

Carboxylic acids are organic compounds containing carboxyl functional group. It is of two types aliphatic and aromatic. Formic acid and acetic acid are the simplest aliphatic acid and benzoic acid is the simplest aromatic acid. The fruits such as lemon, grape, orange and green apple also contain carboxylic acid.   This video explains how to identify carboxylic acids using some simple tests.  

Detection of Sugar in Urine

Sugar (glucose) is usually present in the urine at very low levels or not at all. Abnormally high amounts of sugar in the urine, known as glycosuria, are usually the result of high blood sugar levels. High blood sugar usually occurs in diabetes, especially when untreated. When the blood sugar is high, there is too much sugar in the fluid leaving the kidney to be reabsorbed, so some sugar passes into the urine.Sugar in the urine can be detected in the laboratory or is easy to detect at home with a urine dipstick test.   This video explains how to…

Purification of Benzoic Acid by Crystallization

Benzoic acid is a colourless crystalline solid. It is highly soluble in hot water, but poorly soluble in cold water. It can be recrystallized by dissolving it in hot water. The hot solution obtained is filtered and cooled. Upon cooling, opaque white crystals of benzoic acid crystallise.   This video explains how to prepare pure crystals of benzoic acid form an impure sample through crystallization.  

Beam Balance

A beam balance is a device used for the determination of the mass of a body under gravitation. It consists of a beam supported at the center by an agate knife edge resting on a support moving inside a vertical pillar. The beam carries a light pointer which moves over a scale. There are two stirrups at the ends of the beam which carries two scale pans of equal masses along with adjusting nuts. These can be adjusted to make the pointer to oscillate within the scale when the balance is raised. The balance is mounted on a platform provided…

Detection of Sulphur in an Organic Compound

Sulphur is a non – metallic chemical element with the symbol ‘S’. It is present in many organic compounds like thiol, carbon disulphide etc. The antibiotics penicillin and the artificial sweetener saccharin etc are also sulphur containing organic compounds. Upon fusion with sodium metal, the sulphur atom in the organic compound is converted to ionic sodium sulphide, which can be extracted by boiling the fused mass with distilled water and is used for the detection of sulphur.   This video explains how to detect the presence of sulphur in an organic compound.  

Conversion of Galvanometer to Ammeter

A galvanometer is a device used to detect feeble electric currents in a circuit. It has a coil pivoted (or suspended) between concave pole faces of a strong laminated horse shoe magnet. When an electric current passes through the coil, it deflects. The deflection is proportional to the current passed. A galvanometer can detect only small currents. Thus, to measure large currents it is converted into an ammeter. It can be converted into an ammeter by connecting a low resistance called shunt resistance in parallel to the galvanometer. Value of resistance is so adjusted that most of the current passes…

Tests for Phenols

Phenols are compounds containing one or more hydroxyl group attached to an aromatic ring. The simplest phenol is carbolic acid having the formula C6H5OH. It is a white crystalline solid. Other example are o,m and p-cresols, catechol and resorcinol.   This video explains how to identify phenol using some simple tests.  

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