The desire of children to learn about physical and chemical phenomena can be satisfied even in the kitchen. Ordinary salt, water, potassium permanganate and citric acid can awaken a young researcher and experimenter in a child's soul.
For young physicists
Why Doesn't The Lemon Sink. For the experiment, you will need a container of water and a whole lemon. Dip the fruit in the water, making sure it doesn't sink to the bottom. This fact is explained by the fact that the peel of the lemon is porous and contains a large amount of air, which helps to stay on the surface. The same principle applies in the case of ice dipped in water. The "floating" of ice is provided by frozen air particles. Now peel the lemon and immerse it in water, due to the increase in density, it will sink to the bottom.
"Evaporation of water". Pour water into two identical glasses, close one of them with a lid. Put both containers on the windowsill, in the sun and forget about the "wards" for a couple of days. After a few days, compare which glass has more water. Explain this to the child by the ability of water to evaporate when the temperature rises and by the fact that the lid did not allow a droplet to escape from the glass.
Dissolve 2 tablespoons of salt in a jar of water, lower the egg. The egg will float! Explain to your child that salt water is dense enough to hold an egg to the surface. Gradually add clean water to the jar, reduce the density of the liquid until the egg sinks to the bottom.
Young chemists
"Invisible Letters". The experience is well known from adventure and detective novels. Draw a picture or write text on a piece of paper with milk. After drying, heat the leaf over a fire, and - oh, miracle! Your message will cease to be invisible.
A similar experiment can be done with lemon juice. On a piece of paper, write the encrypted message with lemon juice or diluted citric acid. Dissolve a few drops of iodine in water and apply to paper. The letters will become as clear as in the case of milk.
"Live Gelatin". Pour 20 g of dry gelatin into ½ cup of cold water. After swelling, place the container in a water bath and heat to 50 degrees Celsius. Pour the resulting mass onto cellophane and let dry. Cut a figurine out of a gelatin plate and place it on a piece of paper. Breathe on the figure and it will begin to move. The reason lies in the fact that your breath heats up the gelatinous mass and moisturizes it on one side. The jelly expands slightly and moves.
"Home crystals". Prepare a strong salt solution so that the new portion of the salt does not dissolve in it. Assemble the frame from the wire, immerse it in a saline solution for several days. Over time, you will see how salt crystals have grown onto the framework. With enough patience, immerse the object again, the crystals will enlarge, and you will have a beautiful creation.
