Five do-it-yourself chemistry experiments

This guide has been updated in September 2020. It was originally published October 2014.

You want to impress your friends by turning bones into rubber? Determine how acidic or basic different items around the house may be? You can be a chemist too with these five chemistry experiments to try at home.

Don’t worry. All the experiments are safe for do-it-yourself chemistry.

Experiment 1. Test for starch in a leaf

Starch is the food of plants. Here is how to test for its presence.

You can get the following ingredients at a drug store like the ‘Matas’ chain.
Ingredients: Two separate plants a glass jar, ethyl alcohol, iodine solution, tweezers, and a pan on the stove

Prepare the two plants by placing one in a dark spot for 24 hours, and the other in a sunny spot such as a windowsill. After 24 hours, fill a saucepan with water, then add some ethyl alcohol onto the pan.

Once the ethyl alcohol in the beaker starts to boil, turn off the heat. Take a leaf from each of the plants, and place them in the hot water for 60 seconds. Then using tweezers dip each leaf into the ethyl alcohol for two minutes. They should begin to turn white. Finally, take out the two leaves and place them into a small dish filled with iodine solution, so that the iodine solution just covers the leaves.

Explanation: Photosynthesis is the process through which a plant converts light and CO2 into energy, which is stored inside the plant.

The chemical formula is the following: 6CO2 + 6H2O ——> C6H12O6 + 6O2,
(Where: CO2 = carbon dioxide, H2O = water, Light energy is required, C6H12O6 = glucose, and O2 = oxygen.)

The hot water is responsible for killing the leaf, while the ethyl alcohol breaks down the chlorophyll so that the green colour is gone. Iodine is a chemical which acts as an indicator for starch, turning blue-black in the presence of starch reddish-brown when there is no starch. The leaf which turned blue-black is the leaf left in the sunny location, which has been performing photosynthesis and producing starch.

Experiment 2. Rubber bones

It is important to have enough calcium in our diets, it keeps our bones strong. This experiment will prove it.

Ingredients: jar large enough to fit a chicken bone, a chicken bone (a leg or drumstick would be best), and vinegar.

Thoroughly wash the bone with hot water, and dry it. Place the bone into the jar and cover it with vinegar, then cover with a lid and let it sit for 3-5 days. Finally, remove the bone, rinse it off, and try bending it.

Explanation: Vinegar is an acid which is strong enough to dissolve away the calcium in the bone. The calcium is what keeps the bone hard, and so once it is dissolved all that is left is the soft bone tissue.

Read also: Five biological experiments you can do at home

Experiment 3. Perform chromatography using candy

Compare the compounds in the dies used for colouring an M&M.

Ingredients: M&Ms candy (one of each colour), coffee filter paper, a tall glass, water, table salt, a pencil, scissors, a ruler, 6 toothpicks, aluminum foil, an empty 2 liter bottle with cap.

Cut the coffee filter paper into an 8 x 8 cm square and draw a line 0.5 cm from one edge of the paper. Make a dot for each of the candy colours equally spaced along the line, with about 0.5 cm from the edge of the paper for the first and last dot. Label each dot with the name of the colour. Take a piece of aluminum foil and place six drops of water evenly spaced out, and one candy of a different colour on top of each water drop. See what it looks like here. Wait for the colour to dissolve into the water, then dispose of the rest of the candy. Dampen the tip of one of the toothpicks in one of the colored solutions and touch it to the labeled dot on the coffee filter paper, making a small dot of colour (2mm approximately).

Then using a different toothpick each time, place dot of each colour onto the coffee filter paper. After all the spots have dried, repeat once again to get more colour on each spot. Do this three times more times. Next add ⅛ teaspoon of salt and three cups of water to the empty 2 L bottle. Screw the cap on and shake the contents until all of the salt is dissolved in the water, which makes a 1% salt solution. Pour the salt solution into the tall glass to a height of 0.5 cm. Place the filter paper in, making sure that the dots are above the water level and wait.

Explanation: The salt solution will began to move up the paper through a process called capillary action. The colour spots will also climb up the paper along with the salt solution, but the colours will end up at different heights on the paper. This is because some dyes stick more to the paper while other dyes are more soluble in the salt solution. This process is called chromatography, where the salt solution is called the mobile phase, and the paper the stationary phase. The dyes that travel the furthest have more affinity for the salt solution (the mobile phase); the dyes that travel the least have more affinity for the paper (the stationary phase).

Experiment 4. Test the pH of household items using cabbage juice

Find out how acidic or basic a household item is.

Ingredients: 1/2 head red cabbage, metal grater, water, pot, strainer, vinegar, detergent, and a glass.

Fill the pot with water, then grate the cabbage into small pieces and place them in so that the water just covers the cabbage pieces. Boil the mixture for 20-30 minutes, then take the dark purple liquid and strain it into a glass. Create the test solutions by diluting the vinegar with water, and mixing the detergent with water. Add a few drops of the cabbage juice to each of the solutions, and note the color changes.

Explanation: The cabbage juice should turn pink in acidic solutions, and green in basic solutions. You can also test the pH of any household items, for example soda water, lemon juice, baking soda mixed with water, or anything you choose. Red cabbage contains anthocyanin, which is a pigment belonging to group of chemical compounds called flavonoids. Anthocyanins gain an -OH at basic pH, but loose it at acidic pH, and this alteration changes the wavelengths of light reflected by the compound. In this way a colour change occurs and it is possible to tell if the substance was acidic or basic.

Read also: Five science experiments for the kitchen

Experiment 5. Use vinegar to de-scale your kettle

Ingredients: calcified kettle, vinegar, water, and a cloth.

Dilute store bought white vinegar with water using a 1:1 ratio (equal parts water and white vinegar). Leave this in the kettle for 60-120 minutes, and do not boil. Then, dump out the water. If there is any lime- scale left, you can use a damp cloth to wipe this away. Finally, rinse off the kettle thoroughly with water. Next time you use it to boil water you will have improved the efficiency of the kettle, as well as the taste of the water.

Explanation In many areas household water contains a high mineral content, including calcium and carbonate, which can stay behind in a kettle when water is boiled and reform as calcium carbonate. The equilibrium inside the kettle prior to boiling can be seen as: 2HCO3- + Ca2+ ⇋ Ca2+ + CO32- + CO2 + H2O. After boiling, some of the CO2 boils off, and thus calcium carbonate is precipitated as calcium carbonate: CO32- + Ca2+ -> CaCO3. Calcium carbonate is soluble in mildly acidic solutions such as vinegar (CH3COOH), according to the reaction: CaCO3 + 2CH3COOH -> Ca(CH3COO)2 + H2O + CO2

And so when vinegar is allowed to react with the calcium carbonate at the bottom of the kettle, it is dissolved and can be easily removed, allowing the kettle to restore energy efficiency and improve the time it takes to boil water.

So there it is! Five chemistry experiments that you can safely try at home.

Want to try out some biological experiments? Here are five biological experiments you can try at home.

universitypost@adm.ku.dk

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