Hydrophobic Sand: Amazing! Magic Sand that Never Gets Wet

Sometimes science looks like magic. Do you know a type of sand that never gets wet? Even if you pour it into water, it stays dry! How amazing!

In this blog we will unveil the mystery of magic sand for you. With scientific explanations, you will learn and understand the principles of hydrophobic sand. At the end, we have also prepared a small science experiment for you. With some simple steps, you can DIY magic sand that never gets wet.

Okay, let’s start.

Curiosity: Why Magic Sand Does Not Get Wet in Water

When we pour the magic sand into the water, you will see a transparent film on its surface. This film keeps the sand particles from dispersing in the water. You can stir the magic sand with fingers to shape in the water. Pouring magic sand of different colors will also create surprising phenomena.

In fact, this is a hydrophobic effect, where the magic sand repels water. In nature, hydrophobic effects are common, and lotus is a typical example. When you press a lotus leaf into the water, you will see the same phenomenon as the magic sand – a transparent film appears on the surface of the lotus leaf!

Interestingly, when you drop water on the surface of a lotus leaf, the drop will roll over the leaf like a crystal ball without leaving any trace. The hydrophobic effect allows lotus leaves to stay dry for a long time, preventing the growth of bacteria and rot. This is the secret that lotus leaves can survive in wet ponds. In fact, we also call this super hydrophobic phenomenon the Lotus Effect.

People applied nature’s inspiration to create the sand we saw earlier that never gets wet. And it has a more formal name – Hydrophobic Sand.

Introduction: What is Hydrophobic Sand

As the name suggests, hydrophobic sand is a type of sand that does not get wet by water. The magic sand mentioned earlier is a kind of hydrophobic sand, and 99% of its ingredients are sand. However, you know, sand has no magic powers.

What really works is the Hydrophobic Coating on the sand surface. But, how does it keep the magic sand from getting wet?

Exploring Hydrophobic Coating and Surface Tension

Let’s zoom in and see the mystery. We take the lotus leaf as an example. It has a large hydrophobic surface and is furry to the touch. Yes, there are many tiny needle-like wax tubes on the surface of lotus leaves, which look like countless tentacles.

Of course, you have to use a very high-power microscope to see them because they are nanostructures. These needle-like wax tubes are hydrophobic, so water cannot wet the lotus leaves and will leave in the direction of gravity.

Besides, water has a high surface tension, which always tends to form spheres with smaller surface area. In short, surface tension is the cohesive force that holds water together as much as possible. Therefore, on a hydrophobic surface, water can instead collect because it is repelled everywhere.

On a normal non-hydrophobic surface, polar molecules will attract water. This adhesion force is greater than surface tension, so the water is stretched, making the contact area between solid and liquid larger. We call this phenomenon wetting.

Generally, the adhesion force of hydrophilic molecules is often greater than the cohesive force of water, making it impossible for water to maintain a spherical shape on non-hydrophobic surfaces.

Reveal How Does Hydrophobic Sand Work

Back to Magic Sand, now we know that every particle of it is hydrophobic, so water cannot wet it. When you pour hydrophobic sand into water, some fine sand will float on the water. This is because of the combination of hydrophobic coating and surface tension, which is how water striders can stand on water.

Although water striders and sand are denser than water, they weigh little and are hydrophobic. The surface of the water will only bend slightly, without causing them to sink.

Hydrophobic molecules prefer to cling to air rather than water. So, there will be a layer of air film on the surface of the magic sand cylinder in the water, which separates the sand and the water. The sand will still be dry when you fish it out.

Another: Is Kinetic Sand Hydrophobic

Educational toys similar to magic sand include kinetic sand, which is also a special type of hydrophobic sand.

The surface of kinetic sand is not a hydrophobic coating, but silicone oil. Oil is not hydrophilic (the opposite of hydrophobic). So, in a sense, kinetic sand is hydrophobic.

However, when you pour kinetic sand into water, you won’t see the same hydrophobic effect that magic sand does. Kinetic sand is far less hydrophobic than magic sand and is actually sensitive to water. And Magic Sand is super hydrophobic.

In fact, you shouldn’t even get the kinetic sand wet, it will become sticky as a result. Luckily you can air dry it. After the water evaporates, the kinetic sand regains its proper fluidity and viscoelastic properties.

Find Out More: Kinetic Sand vs Magic Sand

Kinetic sand and magic sand are both hydrophobic sands, but they are completely different, whether in air or water. The only thing they have in common is that they are all sand.

	Kinetic Sand	Magic Sand
Ingredients	Sand and silicone oil	Sand and hydrophobic coating
Play	Air or land. Build sandcastles on the table or floor or use molds to shape them.	In the water. Pour the sand into a clear jar or cup and shape it with your fingers or a mold.
Hydrophobicity	Poor, sensitive to water, you cannot put it in water	Good, never gets wet and you can shape it in water
Wet and Dry	Never dries out	Never gets wet
Viscoelasticity	Good. Non-Newtonian fluids can flow slowly. You can keep sand models for a long time	Poor. It is dry in the air and has strong fluidity. But it flows slowly in water
Suitable Age	Suitable for children over 3 years old to exercise hand muscles and creativity	Suitable for students over 6 years old, used for scientific observation experiments, learning about hydrophobic phenomena, and stimulating thinking

Solve! How to Get Hydrophobic Sand Wet

Currently, we realize magic sand with a hydrophobic coating. If we destroy this coating, the hydrophobic sand will become regular and we can wet it.

Physical Grinding

We can crush the hydrophobic sand with a rolling pin or food processor. This will expose the sand inside the coating. However, since the particles of hydrophobic sand are fine, you may not be able to grind it into smaller pieces. Also, most hydrophobic coatings are very hard and difficult to break.

Chemical Dissolution

Some chemical solvents can dissolve hydrophobic coatings. For example, we can use ethanol (alcohol) to remove the waxy hydrophobic coating on the lotus leaves. When you add household detergent or soap to water, then stir the hydrophobic sand for a while. You will find that the magic sand turns into regular sand.

Oh, don’t underestimate the hydrophobic coating because of this.

In fact, there are many kinds. Industrial hydrophobic coatings are highly solvent-resistant and cannot be destroyed by most corrosive chemical solvents like acid. Not only is it self-cleaning, it also protects the substrate from corrosion for a long time.

For example, fluoropolymer hydrophobic coating is said to have a protection period of up to 20 years, while ordinary coatings only 10 years.

Of course, industrial hydrophobic coatings are expensive and toxic, and no one would apply them to children’s toy sand.

Parents Concerns: Is Hydrophobic Sand Toxic

As we mentioned earlier, the main component of hydrophobic sand is natural sand, which is non-toxic. Since it is a toy for kids, people take extra care and caution while making it. The ingredients we use are all clean and natural, ensuring sterility and safety.

In addition, countries around the world have strict safety standards for toys, such as ASTM and EN71. These standards ensure that all qualified Magic Sand toys are totally safe and non-toxic, or they won’t be on the market. Therefore, when you buy hydrophobic sand, you can ask the supplier or manufacturer to do relevant tests or check the certifications.

Is Hydrophobic Sand Edible

Obviously, hydrophobic sand is not edible. Who wants to eat sand? The terrible texture and taste will just make you spit it out instead of swallowing it. We can trust that most children and students do not eat sand.

However, there are exceptions to everything. So we have to emphasize that hydrophobic sand is not edible again! It’s a toy, not food, don’t eat it!

Is Magic Sand or Kinetic Sand Toxic for Dogs

Pets are as important as children in families, but they are also fragile and require our care. We have introduced the harm of playdough to dogs in the article “Is Playdough Toxic to Dogs? Solve and Keep Pets Safe!“. You can click on it to read more.

Currently, there is no research or data indicating that magic sand or kinetic sand is toxic to dogs. However, dogs’ digestive systems can’t handle sand, which can make them sick.

Dogs and cats are curious about things made by humans, but they rely on their sense of smell to understand things. Sometimes, certain scents can cause them to mistakenly think that kinetic sand or magic sand is some kind of food. Moreover, their hands (front paws) are not as flexible as ours, and they are better at picking up prey with their mouths.

Sometimes dogs don’t want to eat sand, they just scoop it up like a tennis ball.

What Happens and What to Do If Kids or Pets Eat Hydrophobic Sand

Often, when children or pets accidentally eat hydrophobic sand, they will spit it out. Believe me, it tastes very bad and no one will like it.

In the unlikely event that a child or pet does eat hydrophobic sand, they can pass the sand through their bowels, if only a little bit. However, if someone eat a lot of sand, you’re better call an ambulance or take them to the nearest hospital for treatment.

Although hydrophobic sand is not toxic, it is a foreign substance and invader to living systems. When the body resists these objects, it may cause some adverse symptoms, such as vomiting, fever, pain, etc. This is the body’s warning: I’m not feeling well and something is hurting me.

Symptoms children may experience:

Stomachache
Vomiting and nausea
Loss of appetite and listlessness
Fever
Cough
Choking
Difficulty breathing or suffocation

Symptoms pets may experience:

Vomiting
Eat less and not excrete
Lethargy and listlessness
Avoid light or hide
Yelling or biting things randomly
Urinate and defecate anywhere

Children will tell you what’s wrong with them, and parents can spot their symptoms quickly. But pets cannot express themselves, and may hide themselves when they feel sick. Therefore, when you find that the pet is reacting differently, you need to be concerned about what is going on with them.

Correct Use and Safe Play with Hydrophobic Sand

As a classic educational toy, we hope that children and students can use hydrophobic sand correctly and play with it safely. Its benefits far outweigh its disadvantages.

Supervise and Accompany

Parents and teachers should supervise and accompany kids or students when they are playing with kinetic sand or doing science experiments with magic sand.

Supervision and companionship can help identify children’s play habits. Sometimes, children may put toys in their mouths. This is unhygienic, even if the toy is non-toxic, dirty hands can introduce viruses into the mouth.

By observing children’s behavior, adults can detect early whether a child has pica. Children with pica eat strange things that can cause them to become ill. If adults don’t care, they will only get worse. Proper guidance and treatment can help them recover.

Adults can guide children’s curiosity while they play and impart simple knowledge to help them learn and understand things more easily.

In addition, the company of parents can also bring the parent-child relationship closer and create a good family atmosphere. This is good for children’s physical and mental development.

Proper Storage Enables Reuse of Hydrophobic Sand

Since Magic Sand is super hydrophobic, it is self-cleaning. That is, you don’t have to worry about it getting dirty. Even if there is dust, you can pour it into the water. The water will carry away the dust and the sand will remain dry and clean.

Magic sand can be kept anywhere, of course, you have to avoid strong winds blowing it away. An interesting idea is to seal it in a clear jar with water. You can either watch it or make sure to reuse it when you take it out.

A variant of hydrophobic sand, kinetic sand is more sensitive to water, so keep it away from moisture and water. Dry boxes or sealed bags are the best options for storing this sand.

Kinetic sand becomes less fluid when it dries out. Add some water to restore it when reused.

Keep Pets Out of the Playroom

It’s difficult to predict your pet’s behavior, so your best bet is to keep them out of harm. If your home has a separate playroom, keep pets outside the door while the children play with hydrophobic sand.

If your children like to play with pets, then it is necessary to teach them how to protect their furry friends and to be kind to animals.

After playing, parents should tidy up and clean the playroom in time, and place toys where pets cannot reach.

Science Experiment: How to Make Hydrophobic Sand

Based on the previous knowledge, we can design a simple scientific experiment to make hydrophobic sand.

Preparations

Some quartz sand
A bottle of hydrophobic coating
A tray or baking sheet

You can dig some sand from the beach, but you’ll want to clean and dry it before you can do the experiment. You can buy hydrophobic coatings online or at paint stores – a small spray can is enough.

Instructions

Step 1: We pour clean and dry quartz sand onto the tray and spread the sand as much as possible by hand. The thinner the sand, the better.
Step 2: Spray hydrophobic coating onto the sand. You can hold down the spray can and move your wrist horizontally or vertically. After spraying one row or column, spray the next row or column. We spray paint at a uniform speed and don’t move too fast to avoid missing spray.
Step 3: Turn the sand over. In theory, you should make every grain of sand upside down, but this is almost impossible. We can just shake the tray and let the sand tumble a bit. If you’re good at cooking, this will be easy.
Step 4: Repeat the previous three steps 2-3 times.
Step 5: The last step is to test the results. Prepare a transparent container, fill it with water, pour in our homemade hydrophobic sand and see its effect!

Notes

Usually, hydrophobic coatings are water-based and relatively safe. But when we spray paint, it is best to wear a mask and gloves to avoid inhaling or spraying the paint on the skin.
Do not spray the coating on the same place for too long. Because when the hydrophobic coating is too thick, the sand will stick together and cannot be dispersed.
Hydrophobic sand can last for a long time, in a sense, it will not go bad.
Although hydrophobic sand is non-toxic, it is not edible. Adults should accompany and supervise children while they are playing.

Set Up A Magic Hydrophobic Sand Game

You already have some magic sand, get a bowl or basin filled with water, and let’s play the game!

We poured the magic sand into the water, then reached in and molded it into the desired shape, like a fish, or a castle. If you can, find some small toys to put in them.

My friend Helena once created a colorful ocean kingdom in her water tank! She put a pineapple house in it, you know, SpongeBob’s home.

She and her daughter Jenny were so into that cartoon. You won’t be surprised that they made Patrick Star, Squidward and Spongebob Squarepants out of hydrophobic sand in that tank!

Disposing of Magic Sand

After playing, never dump the water and sand together. Hydrophobic Magic Sand may clog your drains because it is insoluble. And you’ll lose the sand and can’t play with it anymore.

We can prepare a bucket and a large clean towel to collect the sand. Wrap the towel around the opening of the bucket and tie it with a rope. Next, pour water mixed with magic sand into the bucket. The water will penetrate the towel and the sand will stay on the towel.

This is a good idea to collect hydrophobic sand. Once the towel has drained, remove it from the bucket and fold it into the shape of a trough. Then we are able to place the sand back into the collection box or bag.

Fishing Net: Easily Collect Color Sand From Water

When you have multiple colors of sand in your tank, the above ideas may cause them to mix together. At this time, what you need is a small fishing net.

We can stick a fishing net into the water, separate the sand into different colors, and fish it out. It’s easy and won’t make a mess. The magic sand dries out of the water and you can just put it back into the container.

Conclusion and Frequently Asked Questions

In short, hydrophobic sand is just a type of sand that never gets wet. Magic sand and kinetic sand are both hydrophobic sand, but they are different.

Magic Sand is a super hydrophobic sand that you can shape it in water. The hydrophobic sand we often say refers to it. Kinetic sand contains silicone oil and is somewhat hydrophobic. But it is sensitive to water and you should not pour it into water.

As long as the hydrophobic coating is broken down, the hydrophobic sand gets wet. We can use physical grinding or chemical dissolution to turn it into the regular one.

With a sprayer of hydrophobic coating and some beach sand, we can make our own hydrophobic sand. Of course its effectiveness depends on whether the coating evenly covers the sand particles. In reality, though, the hydrophobic coating sometimes costs more than what you’d pay for magic sand toys.

Q1: Can magic sand get wet?

Magic Sand is a hydrophobic sand, it does not get wet. However, if you use certain tricks, you can make it lose its magic. For example, two tablespoons of detergent can dissolve the hydrophobic coating on the surface of magic sand, turning it into regular. And, of course you can wet regular sand!

Q2: What is the difference between magic sand and regular sand?

In the air, magic sand looks like regular sand, but it behaves completely differently in water.

Regular sand is hydrophilic, it will get wet whenever it comes into contact with water. But as we know, the magic sand repels water. When you pour regular sand into water, it forms a tiny pyramid at the bottom of the water, like an hourglass. Then the magic sand will form a long cylinder.

When you stir water, Regular sand disperses, making the water cloudy. Once left to sit, the sand will sink to the bottom, allowing the water to return clear. But the magic sand will be like bubbles, floating anywhere in the water. It won’t make the water cloudy!

Magic sand in the water is much more fun than the regular one!

Q3: What is magic sand used for?

Magic Sand serves little purpose other than for children to play with and make scientific observations. Although historically, scientists have planned to use magic sand to clean oil from the sea surface. Because hydrophobic sand can absorb oil. After it sinks into the water, people could capture and collect it for cleaning purposes.

However, the reality is that after many improvements, Magic Sand has become a favorite and frequent visitor in the toy market and science classrooms.

Q4: Is hydrophobic sand reusable?

Yes, hydrophobic sand is reusable since it is dry when removed from the water. In addition, the self-cleaning function of the hydrophobic coating keeps the sand free of dust and bacteria.

However, there is still a risk of mold growing when hydrophobic sand is left in water for a long time. This is not because the sand is moldy, but the bacteria can grow where the water meets the air. If you want to preserve your sand creations in the water, it is best to cover the water tank to prevent mosquitoes or bacteria from breeding.

Magic sand washed with soap or detergent will lose its hydrophobic coating and turn into regular. It’s irreversible and you can’t use it anymore.

Q5: What is the common name for hydrophobic sand?

The name of hydrophobic sand seems a bit complicated, and people also call it Magic Sand. It is so different from regular sand that it seems to have some kind of magic.

Commercially, people prefer the name Magic Sand because it arouses consumers’ curiosity and desire to purchase. Of course, in science classes, teachers will also use magic sand to keep students focused. After all, hydrophobic sand looks more unfamiliar and complicated.

But hydrophobic sand gives you a more direct understanding of its science.