Separating sand from salt is a fun science experiment you can do at home. If you've always been interested in the scientific concept of solubility, separating these two elements is an easy way to prove it. Whether you are at home or in the classroom, know that it is a procedure that does not involve any difficulties and gives you the opportunity to see a scientific phenomenon with your own eyes.
Steps
Part 1 of 2: Run the Experiment
Step 1. Gather the materials
As this is a simple and inexpensive experiment, you don't need any laboratory instrumentation or equipment. Here's what you need:
- Salt. Generally, there is always salt in the kitchen, but in an emergency you can take the sachet that is supplied in fast-food restaurants;
- Sand. Usually, it is not difficult to obtain, although its availability also depends on the area where you live;
- A strainer or filter for American coffee. The latter is not essential, but it is useful when you have to filter the sand from the salt water. In most cases, the strainer is easier to use;
- A pan and a heating element. If you are in a chemistry lab, it goes without saying that a flask and a Bunsen burner are even better. It is advisable to have a second pan or plate available in which to pour the filtered salt water.
Step 2. Mix the sand and salt in equal parts in the pot
Measure your doses accurately. Shaking the container a little, the two substances should blend very well with each other; However, if this method doesn't work, mix them up until you can tell one from the other.
- To perform a controlled experiment, do your best to keep the proportions of salt and sand the same.
- You should have a tablespoon of salt and as much sand, which equates to about 15g of each ingredient.
- It is best to use reduced dosages; the experiment will still lead to the same result, but you will have fewer things to fix and clean when finished.
Step 3. Add water to the sandy mixture
If you have combined about 10g of salt with 10g of sand, add about 100ml of liquid or just enough to cover the entire mixture.
- If you use too much water, you have to wait a long time for it to evaporate completely.
- It is not necessary to measure the various ingredients perfectly, but this way you can get consistent results when you repeat the experiment.
Step 4. Heat the mixture
Heat is the active factor that allows the particles to "mix", as well as excite the salt and dissolve it in water. If the salt you poured has collected in lumps, mix the solution; it might be interesting to watch the melting process, so keep your eyes peeled!
- A medium stove fire is more than suitable for this stage.
- If you don't want to interfere with the dissolving process, you can let the mixture sit overnight.
- Remember not to bring the water to a boil, otherwise the liquid will evaporate and you have to start the experiment all over again.
Step 5. Filter the sand from the salt water
Now that the salt has completely dissolved in the water, it is time to separate the sand from the solution; to proceed, pour the mixture through a colander placed over a pot, plate or container to collect the salt water.
Pouring the water into a pot is obviously the best solution, since in this way it is ready to be boiled; if you don't have a colander, you can scoop out the sand with a spoon, but this is a very long process
Step 6. Boil the salted water
In order to completely separate the salt from the sand, you need to return it to a solid state, which you can achieve by bringing the water to a boil. Put the pot on the stove and let the water boil, wait for it to evaporate completely and turn off the flame; at this point, you should see the salt at the bottom of the pan.
- The boiling temperature of salt is much higher than that of water. To protect the pot and avoid burning it, you should keep the stove on a relatively low flame; with this technique, you need to wait a little longer, but it's not worth speeding up the process and taking the risk of spoiling everything.
- At this point, you can retrieve the salt and transfer it to a container near the sand to enjoy the result if you wish.
Part 2 of 2: Note the Observations
Step 1. Define the goal of the experiment
Sometimes, this is obvious, but it's a good idea to have a definite and real purpose when running an experiment; in this case, you want to demonstrate the concept of "solubility". This word indicates the ability of a substance to completely dissolve in a liquid.
While the one described in this article is a pretty straightforward experiment, you can find more gratification when drafting the report
Step 2. Make observations
An experiment is meaningless if it is not viewed with a critical eye. By getting used to taking notes during laboratory tests, you can have a more complete experience and become aware of things that you would otherwise overlook. You should also write down the obvious, so that you can get the sense of the whole phenomenon later; study the basic movements and the changes that take place, write down everything that is happening.
- Although the salt dissolves in hot water, it remains intact.
- In order for the salt to dissolve, it is necessary to heat the water.
- Salt does not evaporate along with water during boiling.
Step 3. Discuss the experiment
A group discussion about the observed phenomena allows to compare the various analyzes. If the test was done in class, it is possible that the one performed by one group led to slightly different results than that of the others. While this difference is likely to be the result of an error, it is always interesting to evaluate new observations and imagine how they might have happened.
If you find yourself alone, compare the data you collected during the experiment with those proposed by videos available on YouTube. Even if you already know the result, it's still worth seeing someone else get it
Step 4. Think about the experiment
As any successful scientist can tell you, most studies are based on continually asking questions. Read the notes and meditate on the observed phenomena. What did you like about the experience? Is there any detail that you could do differently if you had the opportunity? Don't just think about the sand and salt, but think about the whole experiment. What happens with different blends? To be a good scientist you have to be above all curious. Here are some questions you might ask yourself:
- "Does the type of heating surface affect the ability of the salt to dissolve?"
- "If I tried to dissolve the salt by mixing it at room temperature, would the experiment be different?"
- "Is the residual salt after the evaporation of the water pure or has it changed in some way?"
Step 5. Expand the original experiment
When you have done the basic one, you should think of other questions that you would like to find answered. For example, if the proportions of the ingredients were not the same, how long would the process take? The separation of salt from sand is a very simple experiment, but the possibilities for a budding scientist are endless.
- For most home experiments, baking soda is a very fun ingredient to use; on the next attempt you can try adding it to the mixture.
- Performing the experiment in a group is much more fun than doing it alone.
Advice
- It is a very simple experiment which does not require group work, but which is much more fun if done with someone else; moreover, doing it in company allows you to discuss the observed phenomena.
- It is not necessary to repeat the procedure, but it is always a good idea to check the results carefully in case something has gone wrong.
