Children have very high practical ability and active thinking. Parents should not prevent their children from behaving freely and encourage them to ask questions and solve problems. Cultivate their interest and perseverance, help children explore the answers to questions, and focus on cultivating children's divergent thinking.
Today I will share with you a little experiment that you can do at home to cultivate children's exploratory and divergent thinking. Parents, try it with your kids!
Experimental materials:
Purple cabbage, hot water, several cups, sugar, lemon, baking soda, alkaline noodles, white vinegar
Experimental steps:< /p>
Experimental steps:
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1. Cut the purple cabbage into shreds or slices, put it in a cup and let it soak in hot water. After 10 minutes, only water and thread will remain.pick up the purple cabbage.
2. Prepare a cup of sugar water, lemon water, sparkling water, alkaline water, white vinegar and boiled water.
3. Pour the water in which the purple cabbage was soaked into sugar water, lemon water, sparkling water, alkaline water, white vinegar and boiled water respectively. This is when you will notice that the water was initially colorless. the liquid is there. New colors, and the colors are different.
Moment of decryption:
Purple cabbage contains anthocyanins. When it encounters substances with different acidity and alkalinity, a chemical reaction will occur, so the color changes overall, it will appear red when used. When it encounters acidic substances, it will appear blue when it encounters alkaline substances, and it will appear purple in neutral liquids.
Isn’t that amazing? Come try it!
(1) Afterhaving closed the switch, it was observed:
①The phenomenon in tubes A and B is as follows: bubbles appear on the electrodes after a certain time. , bubbles appear in tubes A and B. The volume ratio of the collected gas is approximately 1:2.
The reason why the gas generated in tubes A and B accumulates at the top: the density of hydrogen and oxygen is lower than that of water.
②The device is well sealed and the readings are correct. However, the volume ratio of the gases in the two tubes at the start of the electrolysis does not respect the ethical ratio. The reason is that hydrogen is difficult to eliminate. dissolve in water and oxygen is not easily soluble in water.
③ From the data in the table, it can be seen that the volume ratio of the gas generated in tube A and tube B from the 8th minute is very close to the ethical ratio.
(2) The phenomenon ine tube C is that the liquid level is increasing. The reason for this phenomenon is that the hydrogen and oxygen generated by the electrolysis of water increase the pressure in tubes A and B, forcing out the water. in tube C., so the liquid level in tube C increases.
(3) From the water electrolysis device, it can be seen that the gas generated in tube A is oxygen and has combustion-promoting properties. If you want to test the gas generated in tube A, you must do so. should use: wooden strips with sparkles.
(4) The electrolysis of water generates hydrogen and oxygen. The symbolic expression of the reaction: 2H2O
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(5) This experiment can show that water is composed of the elements hydrogen and oxygen and is composed of water molecules. each water molecule is composed of two hydrogen atoms and one oxygen atom
(6) Pure water has poor conductivity and the experiment is slow, so a small amount Sulfuric acid or hydroxide is often added to water. Sodium is used to improve the conductivity of water.
So the answer is: (1) ① Bubbles appear on the electrode after a certain time, the volume ratio of the gas collected in tube A and the tube. B is approximately 1:2. , hydrogen and oxygen ② Hydrogen is difficult to dissolve in water and oxygen is not easily soluble in water ③8) The liquid level increases and hydrogen and oxygen are generated by electrical decomposition; water increases the pressure in tube AB and squeezes the water in tube C. Therefore, levels itau of liquid in tube C increases (3) Wooden strips with sparks (4) 2H2O
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