Chemistry
Chemistry projects for class 9 and 10: 44 ideas.
Each project below opens to its own page with what it shows, the science behind it, the materials, safety, step-by-step instructions, what you should see and viva questions. Many can be made from things at home; where a kit helps, the page links one.
Other subjects for class 9 and 10: Physics, Biology, Maths, Earth and space, Electronics and robotics, Environment, Computing and coding.
Red cabbage indicator
Red cabbage juice changes colour with acids and bases: pink or red in acids, purple when neutral, and blue, green or yellow in bases.
Lemon and potato battery
Two different metals in an acidic juice make an electric cell, turning chemical energy into electrical energy. One lemon gives less than one volt, so several are joined in series to light an LED.
What makes iron rust?
Iron rusts only when both air (oxygen) and water are present, and salt water speeds it up. Nails kept dry, or in boiled water sealed with a layer of oil, stay bright.
Paper chromatography of inks
Many inks are mixtures of colours. As water climbs the paper, each colour travels a different distance, depending on how well it dissolves and how strongly it sticks to the paper.
Electrolysis of water
An electric current splits water into hydrogen at the negative electrode and oxygen at the positive one. About twice as much hydrogen as oxygen collects, which matches the formula H₂O.
pH of household substances
pH measures how acidic or basic a solution is on a scale from 0 to 14, with 7 neutral. Universal indicator or pH paper shows the value by its colour.
Temperature and the rate of a reaction
An effervescent tablet dissolves faster in warm water, because the particles move faster and collide more often and with more energy. Crushing the tablet speeds it up too, by giving it more surface area.
Simple food adulteration tests
Some adulterants show up with simple tests: starch in milk, paneer or khoa turns blue-black with iodine, and sawdust or brick powder in spices floats or settles when the powder is sprinkled on water.
Comparing water hardness of local samples by soap drop count
Hard water contains dissolved calcium and magnesium salts that react with soap to form scum before any lather can form. Counting the drops of a standard soap solution needed to get a lasting lather ranks tap, borewell, RO, rain and bottled water from softest to hardest.
Testing milk for added water, starch and detergent
Three quick tests catch the commonest milk adulterants: a drop on a tilted plate flows slowly for pure milk but runs fast if watered, iodine turns blue if starch was added to thicken it, and shaking with water gives a thick lather if detergent was mixed in. The project compares packet, dairy and loose milk.
Is the honey pure? Kitchen tests against sugar syrup
Pure honey is a very concentrated sugar solution with little free water, so it behaves differently from honey diluted with sugar syrup: it sinks as a lump in water instead of spreading, is not soaked into blotting paper, and forms a thread between the fingers. Running the tests on branded, local and home-made syrup samples shows what each test can and cannot tell.
Rate of reaction and surface area: whole, halved and crushed tablets
An effervescent tablet fizzes in water as its citric acid and bicarbonate react. The same tablet crushed to powder finishes in a fraction of the time, because the reaction happens only at the solid surface and powder has far more surface. Timing whole, halved, quartered and powdered tablets gives a clean rate curve.
Rate of reaction and concentration: vinegar strength by mass loss
When baking soda reacts with vinegar, the carbon dioxide escapes and the flask gets lighter. Following the mass on a balance every 30 seconds gives a rate curve, and repeating with diluted vinegar shows that the rate falls as the acid concentration falls, while the total gas depends only on how much acid was present.
Electroplating a steel key with copper from copper sulphate
Passing a small current through copper sulphate solution deposits a layer of copper on the object connected to the negative terminal, while the copper anode slowly dissolves to replace the copper ions. A clean steel key or coin comes out with a bright copper coating.
Which cold drink is most acidic? Baking soda drop count
Fizzy drinks and juices contain phosphoric, citric and carbonic acids. Counting the drops of a fixed baking soda solution needed to neutralise a measured volume of each drink, watched with a natural indicator, ranks them by acid content and links the result to tooth enamel damage.
pH of tea and coffee against brewing time and added milk
Tea and coffee are mildly acidic, and the acidity depends on how long they brew and whether milk is added. Measuring pH with indicator paper for black tea, green tea and coffee brewed for different times shows how extraction of acids changes with time and how milk partly neutralises them.
Corrosion rate of iron nails against salt concentration
Rusting is an electrochemical process that speeds up when the water conducts better. Nails kept in water with 0, 1, 3.5 and 10 percent salt for two weeks, then cleaned and weighed, show that salt accelerates corrosion, which is why vehicles and ships near the sea rust faster, and also that very strong brine slows it again.
Comparing vinegar brands by drop titration with washing soda
The acetic acid content of vinegar can be compared by titrating a measured volume with a standard washing soda solution until an indicator changes colour. Running three brands and a home-made dilution ranks them by strength and, with a simple calculation, gives an approximate percentage of acid to compare with the label.
Which antacid neutralises the most acid? A vinegar drop count
Antacids are bases or salts of weak acids that react with acid and neutralise it. Counting how many drops of vinegar one tablet can neutralise lets you compare brands fairly, per tablet and per gram.
How much calcium carbonate is in an eggshell? Mass loss in vinegar
Eggshell is mostly calcium carbonate. When it reacts with vinegar it gives off carbon dioxide, so the loss in mass of the flask tells you how much calcium carbonate was present.
Hot or cold? Temperature change when different solids dissolve
Dissolving some solids makes the water colder (endothermic) and dissolving others makes it warmer (exothermic). The reason is the balance between the energy needed to break the solid apart and the energy released as water surrounds the particles.
Iron nail in copper sulphate: weighing the copper that appears
A more reactive metal pushes a less reactive metal out of its salt solution. Iron displaces copper from copper sulphate, and the mass of copper formed can be compared with the mass of iron used.
Cooling curve of candle wax: where the temperature stops falling
When liquid wax freezes it gives out latent heat, so the temperature stays nearly steady while it solidifies. The flat part of the cooling curve marks the freezing point.
Does salt raise the boiling point of water? A measured test
A dissolved solid raises the boiling point of water, and the rise grows with the amount of solute. This is called boiling point elevation and is a colligative property.
Charles’s law with a sealed syringe in cold and hot water baths
A fixed amount of gas at constant pressure expands steadily as its temperature rises. A graph of volume against temperature is a straight line that points to about minus 273 degrees C.
Catalyst race: which kitchen catalyst breaks down hydrogen peroxide fastest?
Catalysts speed up a reaction without being used up. Yeast and raw potato contain catalase, an enzyme that breaks hydrogen peroxide into water and oxygen, and the volume of oxygen collected measures how fast it works.
Dyeing cotton with turmeric and onion skin: does a mordant help?
Many natural dyes wash out of cotton unless a mordant is used. A mordant such as alum forms a link between the dye and the fibre, making the colour stronger and more lasting.
Spinach leaf pigments separated by paper chromatography with Rf values
A green leaf contains several pigments. Paper chromatography separates them because they travel up the paper at different speeds, and the ratio of distances, the Rf value, identifies each one.
Bohr atom models for the first ten elements with beads and wire
Electrons fill shells around the nucleus in order: two in the first shell and up to eight in the second. The models show how this explains the valency of the first ten elements.
Ball and stick molecules of water, CO2 and methane from clay and sticks
Atoms join to form molecules in fixed shapes. Water is bent, carbon dioxide is straight and methane is a tetrahedron, which affects their properties.
Periodic table wall chart of the first 20 elements with shell cups
Elements in the same column have the same number of outer electrons and similar properties. The chart shows the pattern of metals, non-metals and noble gases.
Does salt or sugar change the boiling point of water?
Dissolved salt or sugar raises the boiling point of water by a small amount that grows with the number of dissolved particles. You measure the rise with a lab thermometer and compare it with the tiny amount people imagine when they salt cooking water.
Why fresh pineapple stops jelly from setting
Jelly sets because gelatin proteins link into a net, but fresh pineapple contains an enzyme, bromelain, that cuts proteins and stops the net forming. Heated or tinned pineapple has lost the enzyme, so the jelly sets normally.
Hard water scale: which kitchen acid dissolves it best?
Hard water leaves chalky scale of calcium carbonate that dissolves in acids and gives off carbon dioxide. You compare vinegar, lemon juice and citric acid solution on chalk as a model of scale and measure the mass lost.
Are all steel utensils magnetic? Testing a kitchen full of metals
Plain iron and some kinds of steel are attracted by a magnet, but many stainless steels with nickel are not, or only slightly. By testing kitchen items you learn why steel types differ and how to sort the metals around you.
pH of garden, farm and roadside soil using red cabbage indicator
Soils can be acidic, neutral or alkaline, and crops grow best in a suitable range. A homemade indicator sorts soils from different places by colour.
Alum against moringa seed powder: which clears muddy water faster?
Coagulants make tiny suspended particles clump together and sink. Comparing alum (phitkari) with crushed moringa seed shows two ways to clear turbid water before filtering.
Steel wool in a jar: how much of the air is oxygen?
Steel wool rusts by using up the oxygen in a closed jar, so water rises in the jar to take the place of the oxygen. The water rises by about one fifth of the air column, showing that air is about 21 percent oxygen.
Homemade cold pack: temperature drop when citric acid meets baking soda
When citric acid and baking soda dissolve and react in water, the mixture gets colder, which shows an endothermic change that takes heat from the surroundings. It is the opposite of burning, which gives heat out.
Solubility against temperature: kitchen salt compared with alum
The amount of a solid that dissolves in 100 ml of water changes with temperature, but differently for each solid. Alum dissolves several times more at 60 °C than at room temperature, while salt barely changes.
Limewater from chuna: is there more carbon dioxide in the breath we blow out?
Limewater turns milky when carbon dioxide passes through it, because insoluble calcium carbonate forms. Breath blown out turns it milky faster than ordinary air does, which shows that exhaled air has more carbon dioxide.
Bringing back tarnished silver with aluminium foil and baking soda
Black tarnish on silver is silver sulphide, and it can be turned back to shiny silver without scrubbing, using aluminium foil, baking soda and hot water. It is a small electrochemical cell in which aluminium is more reactive than silver.
Yeast as a catalyst: foam height from 3 percent hydrogen peroxide
Hydrogen peroxide breaks down very slowly on its own but very fast when yeast is present. Yeast contains the enzyme catalase, a catalyst, and the oxygen released makes a tall foam with a little dish soap.
Tyndall torch beam: telling solutions from colloids and suspensions
A torch beam is invisible in clear salt water but shows up as a bright path in dilute milk or starch water. The particles of a colloid are big enough to scatter light, and those of a true solution are not.