Suction cup holds onto to surfaces | Atmospheric Pressure | Physics KClassScienceChannel 2024-10-17 | Suction cup holds onto to surfaces | Atmospheric Pressure | Physics
Leaves are waxy | Living Things | Biology KClassScienceChannel 2015-07-24 | Here we take a colocasia leaf and use a dropper to put water drops on the leaf. We see that the water does not get absorbed but from water droplets due to the waxy nature of the leaf. The waxy nature of the leaf ensures that water flows off the leaves during rain, allowing the leaf to remain in contact with air so that it can absorb oxygen.
Cleansing action of soap | Chemical reactions | Chemistry KClassScienceChannel 2015-07-22 | This video explains why soap is used to remove oil and grease. We know that oil and water do not mix. So, water alone cannot remove oil stains. In this video we see that even after the 2 liquids are mixed together vigorously in a test tube they separate, with the oil lying above the water. However, when in addition to water and oil, some liquid soap is added and the mixture is vigorously shaken, the separation of oil and water is not seen. This is because soap has both hydrophilic and hydrophobic ends. The hydrophilic end combines with water and the hydrophobic end with the oil allowing the formation of an emulsion. This property of soap allows oil to combine with it and so soapy water can remove oil stains.
Making a thermometer with a jar and straw | Heat | Physics KClassScienceChannel 2015-07-07 | The working principle of a thermometer is the expansion and contraction of a liquid on heating and cooling respectively. This activity uses coloured water to give a visual demonstration of how a thermometer works. We take some coloured water in a jar and fix a straw in the cap of the jar with plasticine as shown. Make sure that the straw touches the bottom of the jar. When we place the jar in a beaker of hot water we see that the coloured water rises up in the straw. This happens as the coloured water expands on absorbing heat. On removing the jar from the beaker we see that the water level falls down. This happens as the coloured water contracts as it loses heat and cools down. So the straw behaves like the bulb of a thermometer and the coloured water behaves like the mercury in a thermometer.
Action of saliva on starch | Digestion | Biology KClassScienceChannel 2015-07-03 | Starch is a component in many foods. When iodine is added to starch it turns blue. That is why, in the experiment, the solutions in both beakers turn blue. On addition of saliva which contains an amylase, a starch digesting enzyme (chemical compound that catalyses the breakdown of starch); the starch gradually converts to sugar. Once the starch is broken down, the blue colour disappears. It is important to know that the salivary amylase requires an alkaline medium to act.
Exothermic and endothermic dissolution | Solubility | Chemistry KClassScienceChannel 2015-07-01 | Dissolution of substances in water sometimes involves exchange of heat. In this video 3 compounds sodium hydroxide, ammonium nitrate and sodium chloride are dissolved in water. The temperatures of the solutions are noted after each dissolution. The sodium hydroxide dissolves with release of heat making it an exothermic dissolution. The ammonium nitrate dissolves by absorbing heat; an endothermic dissolution. Only the sodium chloride dissolves with a marginal change of temperature.
Work and pressure | Pressure | Physics KClassScienceChannel 2015-06-30 | In this activity we see that work has to be done against pressure. Tape a balloon to a straw as shown and place it inside a plastic bottle whose mouth has been sealed with plasticine. When we try to inflate the balloon, we find that it can only be inflated slightly. The air sealed inside the bottle cannot escape and contracts as the balloon inflates. Thus, we have to do work not only in inflating the balloon but also to contract the trapped air.
Diffusion in liquids | Atoms and Molecules | Physics KClassScienceChannel 2015-01-05 | We take some water in a petri dish and add some lead nitrate and potassium iodide to opposite ends of the dish as shown. After a while, we see that a yellow line appears in the centre of the dish, neatly dividing the dish into two parts. This is the precipitate of lead iodide that is formed due to the reaction of the two salts. The salts dissolve in water and the ions are diffused in the solution. As the ions move away from areas of high concentration to areas of low concentration, they meet each other and react to produce the yellow lead iodide precipitate in the centre of the dish.
Pulse rate | Circulation | Biology KClassScienceChannel 2015-01-02 | The pulse is generated in an artery when its wall swells and contracts during heart beat. When the heart contracts the blood it contains is pumped out under pressure and this pressure wave travels through the arteries. It can be felt wherever the artery can be compressed against a bone. The pulse rate is the same as heart rate. It is measured in number of beats per minute.
Oxidation of Copper | Metals | Chemistry KClassScienceChannel 2014-12-31 | The video shows the oxidation of copper. When copper is heated in a flame, it loses its characteristic reddish brown colour. This is due to a chemical reaction between the copper and the oxygen in the air. Copper and oxygen combine to form a new compound called copper oxide which is black in colour.
Air pressure bursts a balloon | Air | Physics KClassScienceChannel 2014-12-29 | In this activity we fill a balloon with air till it bursts. As the balloon is filled with air continuously, it stretches to a point where the force exerted by the air molecules on the inside exceeds the elastic capacity of the balloon, causing the balloon to burst. The capacity of air molecules to exert a force in this manner tells us that air exerts pressure.
Stethoscope | Circulation | Biology KClassScienceChannel 2014-12-26 | Doctors use the stethoscope to amplify the sounds in the body. In this video a simple stethoscope is made using a funnel, tube and a balloon. The balloon is stretched across the wide end of the funnel like a diaphragm. The narrow end of the funnel is inserted into a tubing. When the balloon diaphragm is pressed against the chest it picks up the sound waves emanating from there and vibrates. These vibrations create pressure waves in the air inside the funnel. These are channeled into the tubing where they undergo multiple reflections and reach the ears of the listener with an amplified effect.
Checking water for dissolved salts | Water I Chemistry KClassScienceChannel 2014-12-24 | Water is a universal solvent and hence, it has many dissolved substances in it, mainly salts. In this video, we test 3 samples of water, namely, hard, tap and salt water; to find out which one has the most salts dissolved in it. A few drops of each of these water samples is subjected to heating on a metal plate. When the water is evaporated, it leaves behind the salt residues. We find that, salt water has the greatest amount of residue left, and tap water the least. Hence, the amount of dissolved salts is most in salt water, and least in tap water.
Balancing a pencil | Force | Physics KClassScienceChannel 2014-12-22 | We see that balancing a pencil on its tip on our finger is a task that is almost impossible. However, if we fix a divider to the tip of the pencil and then try to balance it by its tip on our finger, we find that we can do it very easily. Using the divider in this manner shifts the centre of gravity of the system to the divider and this allows us to balance the pencil easily.
Function of our eyes | Our Sense Organs | Biology KClassScienceChannel 2014-12-19 | This activity shows how we rely on both our eyes in order to determine depth and distance. This property is termed as binocular vision. As shown in the video it is easy to put a cap on a pen when we use both our eyes but difficult to do so with only one eye. This is because each eye produces a slightly different image and our brain process these two images in order to estimate information about depth and distance. With only one eye open the brain cannot figure out depth and distance easily.
Thermal decomposition | Chemical reactions | Chemistry KClassScienceChannel 2014-12-17 | The break down of a substance into other simpler substances under the effect of heat is called thermal decomposition. When lead nitrate is heated in a test tube, a brownish yellow gas is formed which is heavier than air. The gas is nitrogen dioxide. The products of the reaction are lead oxide, nitrogen dioxide and oxygen.
Sun and navigation | Light | Physics KClassScienceChannel 2014-12-08 | In this activity we see how to use the sun as a tool for navigation. Mark the shadow made by an upright stick twice, at an interval of around 15 minutes. Join the two marks with a straight line and draw a second line perpendicular to this line. As the sun moves from east to eat in the sky, the shadow moves from west to east. Thus the first mark denotes west while the second mark denotes east and north and south can now be marked on the perpendicular line.
Momentum | Force | Physics KClassScienceChannel 2014-12-01 | In this activity we take two batteries of different sizes and roll them down an inclined plane. We find that the heavier battery rolls to a longer distance. As the final velocity of an object on an inclined plane is constant and independent of mass, the large battery has more momentum than the small battery as it is heavier. This higher momentum allows it to roll to a larger distance.
Soil Has Water I Soil I Biology KClassScienceChannel 2014-11-28 | In this video, we prove that soil contains water. We take a soil sample in a test-tube and heat it over a burner. After a while small condensed water droplets appear along the sides of the test-tube and vapours are seen coming out.
Esters | Hydrocarbons | Chemistry KClassScienceChannel 2014-11-26 | In this video we see how an ester is generally produced from an alcohol and a carboxylic acid. We mix some ethanol and glacial acetic acid and add a small amount of concentrated sulphuric acids as a catalyst, then place the solution in a warm water bath for a few minutes. Cool the solution by pouring it in a beaker containing water and you will get a pleasant smell which is a characteristic of ester. Esters occur naturally in the essential oils of many plants and are widely used to mimic these odours in artificial flavourings and fragrances.
Disappearing beaker | Light | Physics KClassScienceChannel 2014-09-29 | Refraction causes light to bend as it passes from one material to another and the amount of bending depending on the refractive index of the material. In this activity we place a small beaker inside a larger beaker. We then fill the small beaker with vegetable oil, allowing the oil to overflow till the large beaker is filled as well. We find that the small beaker disappears when we do this! The glass of the beaker and the vegetable oil have refractive indices that are almost equal. Thus , as light passes from the small beaker to the oil outside, the light does not bend too much and we cannot see the small beaker.
Water and Milk Bubbles | Nutrition | Biology KClassScienceChannel 2014-09-26 | In this video we see that when we blow air into water and milk, milk produces bubbles that last longer than water bubbles. The reason is that milk contains proteins which form a stronger film over the bubbles. Water lacks proteins and hence the bubbles burst quickly.
Percolation rate in different types of soil | Soil | Biology KClassScienceChannel 2014-07-17 | In this activity, we measure the percolation rate of different kinds of soils like sandy soil, loamy soil and clay. Percolation rate is the speed at which water flows though a column of soil. Take three identical conical flasks with funnels and plug the funnels with some cotton as shown. Add 20 grams of sandy soil, loamy soil and clay in the three funnels, then slowly add 50 g of coloured water over the soil and leave the flasks undisturbed for some time. After a while, pour the water collected in the flasks into three beakers. You will see that the flask under the sandy soil has the most water and the flask under the clay has the least water. The sandy soil has the largest particle size while the clay has the smallest particle size. This tells us that the percolation rate depends directly on particle size and is the highest for sandy soil while the clay soil has the highest retention capacity.
Solute And Solvents I Solutions I Chemistry KClassScienceChannel 2014-07-03 | In this video, there is a glass containing marbles, which represent the solvent molecules. They have spaces between them. Dry sand, representing solute molecules,is added to this glass of marbles.The sand seeps into the spaces between the marbles, but both retain their original properties. So, a solution consists of solute molecules filling spaces between the solvent molecules.
How easy is it to break an egg? | Pressure | Physics KClassScienceChannel 2014-05-05 | Do you think it is easy to break an egg? The answer to that depends on how you try to break it. If you hold an egg between your palms along the long axis and push your palms inwards, you will find that the egg will not break. However if you hold an egg between your palms about the short axis and push your palms inwards, you will find that the egg will break. The ellipsoidal structure of the egg makes its much stronger and less likely to break about the long axis.
Wash hands before meals | Hygiene | Biology KClassScienceChannel 2014-05-02 | This activity shows in a simple manner why it is important to wash hands before meals. Washing hands has been shown to the most cost-effective and convenient way to significantly reduce the spread of infectious diseases. Further reading on the Center for Disease Control's website:http://www.cdc.gov/handwashing/show-me-the-science-hand-sanitizer.html
RGB pixels | Light | Physics KClassScienceChannel 2014-03-24 | When we sprinkle water droplets on a screen of a CRT television, we see spots of red, green and blue in the water droplets. A CRT lights up the screen by the means of phosphors coated on the inside surface of the screen. These phosphors are present in groups of three - red, green and blue. The various colours produced on the screen are a result of by lighting the appropriate phosphors at the appropriate intensity. The water droplets allow us to see the pixels by magnifying them.
Lemon juice turns brown on heating | Irreversible change | Chemistry KClassScienceChannel 2014-03-20 | In this activity, we see an example of an irreversible change. An irreversible change is a change where an object cannot be taken back to its original state. We vigorously heat a piece of paper on which we have written a secret message using lemon juice. We see that as the paper is heated, the message appears as brown writing. This happens because heat turns the acid present in the lemon juice brown.
Potato experiment | Osmosis | Biology KClassScienceChannel 2014-02-28 | In this experimental set up 3 potatoes - 2 raw and 1 cooked are used. All 3 have a cavity and are placed in a tray of water. One of the raw potatoes and the cooked one have salt filled in their cavities. The cavity in the other raw potato is left empty. When the potatoes are observed some time later, the salt in the raw potato is dissolved in water, while the salt in the cooked potato is still in the solid form with no water. The 3rd potato is without water. What happened here is like this. Because of osmosis, the cells of the potato surrounding the salt filled cavity gave out water into the cavity. This water is drawn from the water lying in the tray. The cooked potato cells are dead and so do not undergo osmosis. So no water is drawn in and the salt remains dry. In the case of the 3rd potato, as there is no salt, the cells do not develop sufficient osmotic pressure to draw in water..
Capillarity and Surface Tension | Surface Tension | Physics KClassScienceChannel 2014-02-24 | In this activity we take two capillary tubes of different diameters and place them in a beaker of coloured water as shown. We see that the water rises in both the tubes and that the narrower tube has a higher level of water. As water adheres to glass, the water molecules near the glass walls climb up the glass surface due to adhesion. In this process they also carry up the water molecules that are away from the walls due to surface tension and a small amount of water rises in the capillary tube, forming a concave meniscus. The height to which the water rises depends on the diameter of the tube. In plants, the water is absorbed by the roots and rises up the trunk due to capillary action.
Is Egg A Solid Or A Liquid | Nutrition | Biology KClassScienceChannel 2014-02-21 | This activity shows that when whisked, the liquid part of an egg, the albumen, appears solid. This is because it maintains its shape like a solid. This happens because, when whisked, air bubbles get trapped in the egg white.
Properties of Metals I Types of Substances I Chemistry KClassScienceChannel 2014-02-19 | This video shows the properties of different metals. All metals, except Mercury are solids in the normal state.Metals can be moulded into sheets and different shapes,making them malleable.They can be drawn into wires,hence, ductile, and are good conductors of electricity.They have a shiny metallic lustre.
Balancing and gravity | Force | Physics KClassScienceChannel 2014-02-17 | When we place a box on the edge of the table as shown, it does not fall down as expected but stays on the table. This happens because we have placed a weight at the end of the box lying on the table. Due to this weight, the centre of gravity of the system (box + weight) moves towards the end of the box with the weight, allowing the table to give support to the system at the centre of gravity and the box does not fall. When we place an empty box on the edge of the table, it falls down as this time the centre if gravity of the system (just the box now) is at the centre of the box and the table cannot give support to the system at the centre of gravity.
Potato vegetative propagation | Reproduction | Biology KClassScienceChannel 2014-02-14 | The potato is an underground stem. The eyes of the potato are nodes from which fresh buds sprout. In this activity a potato is cut up into small pieces and provided with water and air. Soon the pieces of the potato with eyes develop buds and grow. They will grow into new plants. This method of reproduction without gametes is called vegetative propagation
Magnet distorts colours in a TV | Magnetism | Physics KClassScienceChannel 2014-02-10 | When we hold a magnet close to the screen of a CRT television, we see that the colours on the screen get distorted around the magnet. A CRT television produces images on the screen by using an electron beam to light up the appropriate phosphors present on the inside of the screen. A magnet deflects the electron beam and distorts the colours produced on the screen.
oxygen volcano | Oxygen | Chemistry KClassScienceChannel 2014-02-05 | Hydrogen peroxide decomposes to form water and release oxygen gas. In the video hydrogen peroxide and liquid soap is mixed. To this mixture some yeast is added. Yeast, a fungus, produces an enzymes called catalysis. This enzyme speeds up the decomposition of hydrogen peroxide. The oxygen gas produced is entrapped in the liquid soap and so the soap rises up in the form of froth, like a volcano.
Mobius strip - II | Measurement | Physics KClassScienceChannel 2014-02-03 | "We take two strips of paper and make a simple loop with one of the strips. We take the second strip of paper, twist it once and then stick the two ends together to make a loop. The resulting shape is known as a Mobius Strip. When we cut the circular loop along the middle as shown, we get two circular loops. however, cutting a Mobius strip along the centre produces a single loop with two twists. This happens because a Mobius strip has only one side and only one edge.Mobius strips are not just a curiosity but also have useful applications. Mobius strips have been used as conveyor belts that last longer because the entire surface area of the belt gets the same amount of wear and as continuous-loop recording tapes to double the playing time. Mobius strips are common in the manufacture of printer and typewriter ribbons, as they allow the ribbon to be twice as wide as the print head while using both halves evenly."
Potassium Iodide and Lead Nitrate reaction | Chemical reactions | Chemistry KClassScienceChannel 2014-01-29 | The video shows the reaction between potassium iodide and lead nitrate. When drops of potassium iodide solution are added to a lead nitrate solution, the products of the reaction are a bright yellow coloured precipitate of lead iodide and a solution of potassium nitrate. This is a double displacement reaction because the cations (potassium and lead) of each reactant combines with the anion of the other reactant forming 2 new compounds.
Working of a megaphone | Sound | Physics KClassScienceChannel 2014-01-20 | A megaphone is used to increase the intensity of the sound so that the sound produced is louder. When we drag a needle across a rough surface as shown, the vibrating needle causes the air around it to vibrate and produces the sound that we hear. When we attach a megaphone to the needle and then drag it across the surface as shown, the megaphone causes a larger amount of air to vibrate as it has a large surface area and the sound produced is louder.
Burning of Carbon compounds | Hydrocarbons | Chemistry KClassScienceChannel 2014-01-15 | In this activity, we explore the behaviour of different carbon compounds on burning. First we burn a few camphor tablets and see that it produces a bright yellow flame whose soot can be easily collected by holding a spoon over the flame. Then we burn a small amount of ethanol and see that it produces a yellow-blue flame which is hotter but less bright. In this case we cant collect any soot on a spoon by holding it over a flame. The difference is due to the number of carbon atoms in each compound. Ethanol only has 2 carbon atoms and can easily produce carbon dioxide while camphor has 10 carbon atoms and all of them are cannot produce carbon dioxide. Therefore we get soot with camphor which has a higher number of carbon atoms. The separation of crude oil into different fuels like petrol, diesel, etc depends on how many carbon atoms are there in the different fuels.
Making of soap | chemical reactions | Chemistry KClassScienceChannel 2014-01-15 | Soaps are formed when fatty acids react with an alkali. The reaction is called saponification. The video shows how to make soap. An alkali, sodium hydroxide, is taken in a test tube. Some vanaspati is added to the test tube and the mixture is heated. When the mixture is shaken, froth collects at the top indicating the formation of soap.
Levers and lifting objects | Simple machines | Physics KClassScienceChannel 2014-01-13 | In this activity we see that lifting a scale by one of its ends requires more effort than lifting it by its centre. In the first case the load is completely on one side of the fulcrum while in the second case the load is distributed evenly on either side of the fulcrum. This change in load distribution allows us the exert less effort in the second case.
K-Class Science Channel KClassScienceChannel 2014-01-09 | Welcome to the largest collection of Science Experiment Videos on the web© 2013 IL&FS Education all rights reserved
Floating egg and Bernoulli Principle | Pressure | Physics KClassScienceChannel 2014-01-06 | Bernoulli's principle states that 'A moving fluid exerts lower pressure than that exerted by a static fluid.' To see this we place an egg in a glass and pour water on it from a height as shown. We see that the egg rises up while the water is being poured and settles down again once we stop pouring the water. As the water was being poured, the static water below exerted a larger pressure on the egg that the moving water above and pushed the egg up. Once the water stops moving, it exerts equal pressure on the egg from all directions and causes the egg to settle down again.
Diffusing Colours I Water I Chemistry KClassScienceChannel 2014-01-01 | This video shows the diffusion property of solutes. Two water soluble colours are mixed separately in coconut oil and both are added simultaneously into a bottle filled with water. Since the oil lies as a separate layer above the water, the colours do not spread initially. But, slowly the colours are attracted to the water in the bottle and start mixing, moving from a region of higher concentration to a region of lower concentration. This will continue until the concentration of solutes is uniform throughout the bottle. This movement of the solute molecules is called diffusion.
Saturated and Unsaturated Fats | Nutrition | Biology KClassScienceChannel 2013-12-27 | This video shows the difference between saturated and unsaturated fats. Saturated fats have only single bonds in their molecular structure. This means they are saturated with hydrogen atoms. These fats are solid at room temperature. Saturated fats are considered a risk factor in heart disease. Unsaturated fats, on the other hand, are considered the healthier option. They are liquid at have room temperature.
Restore a rose | Sulphur | Chemistry KClassScienceChannel 2013-12-25 | Sulphur dioxide is a toxic gas which is produced when some sulphur is heated in a test tube. In this video, we see that a rose petal placed at the mouth of the test tube loses its colour and becomes pinkish white displaying the bleaching effect of this gas. Sulphur dioxide is a reducing agent and causes the chromospheres in the rose petal to lose colour. When this bleached rose petal is placed in a dark environment for a couple of days, the colour of the petal is restored. This is because the bleaching is temporary and as the oxygen in the atmosphere acts on the bleached petal, it deoxidizes the reduced dyes, restoring their colour.
Melting and freezing chocolate | Heat | Physics KClassScienceChannel 2013-12-23 | We take a bar of chocolate and heat it in a beaker as shown. We see that the bar loses its shape as it melts and becomes a liquid after some time. We pour the molten chocolate into a bowl and place it into a freezer. We see that the molten chocolate freezes into the shape of the bowl.
Buoyancy lab: fun with aluminium foil | Force | Physics KClassScienceChannel 2013-12-23 | When an aluminium foil is placed in a tub of water, we see that it sinks. This is expected as aluminium is denser than water. When some foil is crumpled and put it in water, we see that it floats even if we try to sink it. On the other hand, if we crumple the first foil that is already sunk, it stays sunk. When we crumple the foil outside, some air gets trapped in the folds of the foil and this trapped air provides the buoyant force that does not allow the crumpled foil to sink. In the latter case, as the foil is crumpled under water, there is no air that can get trapped in the folds of the foil and the foil remains sunken.
Circles from straight lines | Our Body | Biology KClassScienceChannel 2013-12-20 | In this video we see an optical illusion in which straight lines drawn on a piece of cardboard paper to become circles when we rotate the cardboard at a high speed. This happens because of persistence of vision.
