Can a glass rod be used instead of a match to light an alcohol lamp?

Experiment: put a small amount of potassium permanganate crystal on the mirror (or glass), drop 2 or 3 drops of concentrated sulfuric acid on potassium permanganate, dip it with a glass rod, and touch the wick of the alcohol lamp, and the alcohol lamp will light up immediately.

Fingers on fire

Steps: Soak the gloves with water, squeeze them dry and put them on your left hand. Soak four fingers in a beaker containing 40% alcohol, and then light them on the flame of an alcohol lamp. In order for all students to see their fingers burning, they can take a piece of paper from their right hand and light it above the fingers of their left hand. When the left hand feels feverish, you can clench your fist vigorously, and the right hand holds the left fist to quickly squeeze the friction gloves, thus putting out the leaking fire. This experiment almost failed.

Principle: In 40% alcohol solution, the boiling point of alcohol is low (78 degrees Celsius) and the boiling point of water is high (100 degrees Celsius). The heat generated by alcohol combustion is consumed by water evaporation, and the water on the wet gloves is first wetted by the handle, so it takes some time to burn alcohol when the fingers feel hot.

Charcoal dance

Take a test tube, put 3-4g solid potassium nitrate into it, fix it upright on an iron clip, and heat it with an alcohol lamp until it melts slowly. Take a bean-sized charcoal and put it in a test tube, and continue to heat it. After a while, you will find that the small charcoal jumps up and down like a dance, and it will also emit red light, which is very interesting.

Drip ignition

Water can put out the fire, but can it be lit?

Experiment: Mix 5 grams of dry sucrose powder and 5 grams of potassium chlorate powder on an asbestos net, stir them evenly with a glass rod, pile them into hills, add 3 grams of sodium peroxide and drop them into water. Half a minute later, white smoke came out of the hill and soon burned.

An unbroken handkerchief.

The burnt handkerchief is actually intact?

Experiment: Soak the cotton handkerchief in the solution with the ratio of alcohol to water of 65,438+0: 65,438+0, then squeeze it gently, hold the two corners of the handkerchief with two crucible pliers, light it on the fire, and shake the handkerchief quickly to extinguish the flame when the flame decreases, and you will find that the handkerchief is still intact.

Principle: when burning, the flame of alcohol is outside the water layer, and the water absorbed in the fiber gap absorbs the heat of combustion and evaporates, so the temperature on the handkerchief can not reach the ignition point of the fiber, so the handkerchief can not be burned.

roll a snowball

Snowballs will also burn.

Of course, it is not the real snowball that burns, but the calcium acetate separated from the calcium acetate solution in alcohol, like white snow, which is made into a ball and burned when it is ignited.

Experiment: Add 20 ml of water and 7 g of calcium acetate to make a saturated calcium acetate solution, add it to100 ml of 95% alcohol, and precipitate a snow-like solid under stirring.

An empty cup will smoke.

White smoke from an empty cup? ?

Experiment: Two clean and dry glasses, one with a few drops of concentrated hydrochloric acid and the other with a few drops of concentrated ammonia water, rotate the glasses to make the drops wet the glass wall, then cover the glass sheet, turn the glass with concentrated hydrochloric acid upside down on the glass with concentrated ammonia water, remove the glass sheet, and gradually you can see a glass full of white smoke.

Abnormal supply:

1, volcanic eruption

Pile a hill in a porcelain dish with fine sand, and leave a round pit the size of a crucible at the top of the hill. 5 grams of potassium permanganate powder is piled in the pit, and a small groove is pressed on the top. Around potassium permanganate, 10g finely ground ammonium dichromate powder is piled up. Drop 1~2 drops of glycerol into a small pot of potassium permanganate with a dropper, and a purple flame can be seen in a moment, and then a large amount of green "volcanic ash" is ejected, which is as lifelike as a volcanic eruption.

Potassium permanganate can react violently with glycerol, and the released heat makes glycerol catch fire. Ammonium dichromate decomposes rapidly when heated to produce green chromium trioxide, nitrogen and water vapor. The volume expands rapidly after decomposition. Because of the high temperature, gas and chromium trioxide are ejected like volcanic eruptions.