Elementary school students can carry out small experiments: mixing eggs with vinegar, generating heat through friction, lighting lamps in water and flying on cushions of air.
1. How to cook eggs with vinegar and prepare special tools: Prepare eggs and vinegar. The method is to put the eggs in the vinegar, and after an hour or two, throw away the original vinegar and replace it with new vinegar, and repeat this several times. Take a look at what happens to the eggs. Has the egg shell become very thin or even disappeared? The reason is that eggshells are mainly composed of calcium. Calcium and vinegar undergo chemical changes. When the calcium dissolves in the vinegar, the egg shell becomes very thin, or even completely dissolved.
2. Friction heat: Hold the copper wire with your left hand and tiground it to the right, letting the copper wire roll between your right hands. the hand will be warm. Hold the copper wire firmly with both hands and bend it several times quickly. The bent area of the copper wire will become hotter and hotter. What is going on? This is because friction between objects can cause heat. Of these two tests, the first test involves friction between the copper wire and your hand. The second test is the internal friction between the internal molecular structure of the copper wire when the copper wire is bent. Both of these conditions are caused by the conversion of mechanical energy into thermal energy through friction.
3. How to “light a lamp in the water” and prepare the tools: Prepare the candles, basin and water. The method involves sticking a thicker candle to the bottom of the container. basin, pour a little water so that the surface of the water is a little away from the surface of the candle andDon't swallow the candle. Light the candle and see if the candle burns below the surface of the water. Think about it: why is there a light underneath. the water ? Be creative: try it. Try burning the candle deeper under salt water or burning it deeper in cold water.
4. and put it in the cup. Leave some hot water in it. Then quickly put the cup back on the smooth table. At this time, gently blow on the cup or push it with a feather, and the glass will easily slide onto the cup. table like a skating machine. Like, there's almost no friction. What is going on ? This is because when the cup is quickly turned over on the table, the hot water in the cup flows out and the wall of the cup is overturned. and the hot water left experiences friction. The heat causes the air to expand, thus slightly lifting the cup on the table. At this time, the cup is no longer in direct contact with the table,but is supported by a support. thin layer of water film and a “flying cushion”. Therefore, the friction between the cup and the table top becomes very low. Therefore, as long as there is a little external force, the cup will slide forward!
1. Cut the lemon (orange) in half (you can cut it into quarters pieces if the fruit is not enough), insert small copper plates and small zinc plates at both ends (be careful not to let the copper and zinc come into contact), repeat four times to obtain four pieces of fruit with copper and zinc plates, then use the wire clamp once sandwiched between two pieces of fruit on adjacent copper and zinc plates.
2. Do not connect the last two remaining wires yet. Connect one end of the two wires to the small bulb (or LED), the other to the sensitive ammeter, and insert a new wire. the middle to connect the pesmall bulb (or LED) and the ammeter.
3. After the connection is completed, the experimental results: the small bulb (or LED) emits dim light and the display on the sensitive galvanometer can be read After the experiment is completed, wash and. recover the experimental materials.