Alpha science classroom：Separate Liquids with Salt

Children may know that some fluids, such as oil and water, cannot be mixed. But did you also know that if two liquids are mixed together, children can put them on a different layer twice? What is the principle? Today, the alpha science classroom uses Separate Liquids with Salt, a chemistry experiment for kids activity, to unlock the chemical mystery of the mixture for children. At the same time, let the children enjoy the growth help and fun brought by science through this kid's science experiment project.

Alpha science classroom: Separate Liquids with Salt，Required Materials

• Four transparent mini cups (two ounces) with lids

• Permanent marker

• Tap water

• Rubbing alcohol (70 percent isopropyl alcohol)

• Table salt

• Set of measuring spoons

• A work area that can tolerate spills

• Ethanol or acetone (can be found in hardware stores) (optional)

• Salt substitute such as potassium chloride or Epsom salt (optional)

Alpha science classroom: Separate Liquids with Salt, step-by-step tutorial

Step 1: The children add a teaspoon of salt to the water in cup 1. What will happen to the salt? Is it soluble in water?

Step 2: The children close the lid and shake the cup for about 20 to 30 seconds. What does the mixture look like?

Step 3: Children use cup 2 (using rubbing alcohol) to repeat the first two steps. How is the salt this time? Does the mixture look different from the water and salt mixture?

Step 4: The children remove the cap of the permanent marker and rotate the tip of the permanent marker in the water in cup 3 for about 10 seconds. Put the lid on the cup and shake for five seconds. Is the ink soluble in water? What is the solution after shaking?

Step 5: The children repeat the previous step with cup 4 (rubbing alcohol). Does the resulting mixture look different? If so, what is the difference? Can you explain these differences?

Step 6: The children next pour the alcohol in cup 4 into the water in cup 3. Close the lid and spin the mixture for 5 seconds. Will rubbing alcohol mix with water? What happens to the color of the mixture? Do you see the individual layers formed?

Step 7: Now, the children add a teaspoon of salt to the mixture in cup 3. Cover the cup and shake for 20 to 30 seconds. What happens when you add salt to the mixture? Does the mixture look different before and after shaking? If so, how does it look different? Can you explain your results? What color is the mixture?

Extra: Can you use salt to separate other liquid mixtures? What about ethanol and water or acetone and water? Try different liquid mixtures to find out!

Extra: Are there other salts (such as potassium chloride, salt substitutes, or Epsom salt) that can be used to separate liquids? Repeat the test, but this time use a different salt than table salt. Do you still see the same result? If not-what is the difference in your results?

Extra: How much salt is needed to separate rubbing alcohol from water? Find out the answer by changing the amount of salt added to the rubbing alcohol and water mixture.

Alpha science classroom: Separate Liquids with Salt, the scientific knowledge behind

Alpha science classroom believes that when the children have completed this step, they should have seen that the salt is easily dissolved in the water in cup 1. (The salt seems to disappear after shaking.) Remember, this is because ionic salt molecules easily bind to polar water molecules. However, the salt is not so easy to dissolve in the rubbing alcohol in cup 2. (Even if you shake it, you can still see the salt.) This happens because alcohol molecules are less polar than water, so salt ions are not so easy to bind to them.

For permanent marker ink, you should have observed the opposite phenomenon. Ink does not dissolve well in water, but it dissolves easily in alcohol, making the latter darker in color. This is because rubbing alcohol also has some molecules that have no charge and are non-polar. This part is more compatible with non-polar molecules (such as marking inks).

When you mix rubbing alcohol with water, the molecules of the latter form hydrogen bonds with water molecules. Alcohol dissolves in water to form a homogeneous solution, so you can no longer distinguish between alcohol and water. However, if salt is added to the mixture, the salt will dissolve in the water and compete with the alcohol for water molecules. Since there are fewer water molecules that can be used to form hydrogen bonds with alcohol molecules, the solubility of the alcohol in the water-alcohol mixture is reduced, and a separate layer is formed on top of the water. The two layers should have different colors, most of the water is clear, and the alcohol is darker. This happens because the marking ink is more soluble in rubbing alcohol.

Salting out is the answer to today’s chemistry experiment for kids project. I believe that children have also seen surprising discoveries. Then, today’s Alpha Science Classroom kid’s Science Experiment Activity is very successful, and the experimental children want to learn more about science. , Follow us!

Alpha Science Toys has also prepared a chemical experiment kit for children to explore the magical mysteries of chemistry, enjoy the fun of chemistry brought by science, and grow into the most powerful magician.