Strange States

If your science teacher were to ask you to name the states of matter, you could probably easily rattle off solid, liquid, and gas. But it turns out the classic trio doesn’t tell the whole story. Under certain conditions, matter can take on other distinct forms. These states exhibit unusual properties and mindboggling behaviors.

All matter is made up of tiny particles such as atoms—the smallest units of elements—or molecules—two or more atoms bonded together. In some circumstances, matter can change from one state to another. For example, an ice cube can melt from a solid into a liquid.

So how many states of matter are there? That depends on who’s counting. Some experts put the number at five. Others say eight. There could be many more, depending on how precisely scientists distinguish between states. Take a closer look at some states of matter, from the familiar to the strange.

Your science teacher asks you to name the states of matter. You could probably easily list solid, liquid, and gas. But the classic trio doesn’t tell the whole story. Under certain conditions, matter can take on other distinct forms. These states have unusual properties and mind-boggling behaviors. 

All matter is made up of tiny particles, such as atoms or molecules. Atoms are the smallest units of elements. Molecules are two or more atoms bonded together. Sometimes, matter can change from one state to another. For example, an ice cube can melt from a solid into a liquid. 

So how many states of matter exist? That depends on who’s counting. Some experts say the number is five. Others say eight. There could be many more. It depends on how exactly scientists tell them apart. Take a closer look at a few states of matter. Some are familiar, but others are strange.  

In a liquid, attractive forces hold atoms or molecules loosely together. That allows the particles to easily flow past one another. A liquid takes on the shape of its container and has a definite volume, or amount of space it occupies.

Forces attract atoms or molecules to one another. In a liquid, these forces hold them loosely together. The particles can flow past each other easily. A liquid takes on the shape of its container. It has a definite volume, or amount of space it fills. 

A solid’s shape and size don’t change easily. That’s because its atoms or molecules are packed tightly together. Attraction between the particles holds them firmly in place.

A solid’s shape and size don’t change easily. That’s because its atoms or molecules are packed tightly together. Attraction between the particles holds them firmly in place.

Plasma forms when a gas is heated to very high temperatures. Negatively charged electrons break away from its atoms or molecules. The result is a mixture of electrons and positively charged particles called ions. Because of these charged particles, a plasma can conduct electricity and generate magnetic fields. These properties set it apart from an ordinary gas. Plasma is the most abundant state of matter in the universe. Most stars consist of plasma. On Earth, plasma is present in lightning bolts, fluorescent bulbs, neon signs, and TV screens.

Plasma forms when a gas reaches very high temperatures. Negatively charged electrons break away from its atoms or molecules. The result is a mixture of electrons and ions. These are positively charged particles. A plasma can conduct electricity because of these charged particles. It can also generate magnetic fields. These properties set it apart from an ordinary gas. Plasma is the most abundant state of matter in the universe. Most stars consist of plasma, but it’s also found on Earth. Lightning bolts, fluorescent bulbs, neon signs, and TV screens contain plasma.

Atoms or molecules in a gas are spaced far apart. A gas has no fixed shape and will spread out in every direction to fill a given space. The volume of a gas can change, for example, if someone transfers it to a larger container or applies pressure to squeeze its particles closer together.

Atoms or molecules in a gas are far apart. A gas has no fixed shape. It will spread out in every direction to fill a space. The volume of a gas can change. If it’s moved to a larger container, it will spread out. Under pressure, its particles squeeze closer together.

Superfluids form when certain liquids, such as liquid helium (He), are cooled to just a few degrees above absolute zero. Some scientists consider them a liquid version of BECs, but superfluids have intriguing properties of their own. Liquids have varying viscosities—some flow more easily than others. A superfluid has zero viscosity. It’s continuously on the move. That’s because its particles are vibrating in unison, like a BEC, so they don’t bump into one another. Theoretically, a stirred superfluid could swirl forever. A superfluid can even creep up the sides and over the rim of its container. Superfluids have been seen only in experiments, but they may form under high pressure in certain stars.

Superfluids develop from certain liquids, such as liquid helium (He). This happens when these liquids are cooled to just a few degrees above absolute zero. Some scientists say superfluids are a liquid version of BECs. But they have their own interesting properties. Liquids have different viscosities. Some flow more easily than others. A superfluid has zero viscosity. It’s always moving. That’s because its particles all vibrate exactly the same, like a BEC. So they don’t bump into one another. In theory, a stirred superfluid could spin forever. A superfluid can even creep up the sides and over the rim of its container. Superfluids have been seen only in experiments. But they may form under high pressure in some stars.

This state has been observed only briefly in lab experiments. Bose-Einstein condensates (BECs) form when gases are cooled to about a millionth of a degree above absolute zero. Absolute zero is the lowest temperature theoretically possible. At room temperature, about 20 degrees Celsius (68 degrees Farenheit), the particles in a gas are “moving randomly, each one doing its own thing,” says Dan Stamper-Kurn, a physicist at the University of California, Berkeley. Near absolute zero, some of the particles slow almost to a standstill and start vibrating with the same energy as one another, like people dancing in perfect unison. In this state, it’s no longer possible to tell individual atoms apart.

Scientists have observed this state only briefly in lab experiments. Absolute zero is the lowest temperature thought to be possible. Scientists cool gases to about a millionth of a degree above absolute zero. That’s when Bose-Einstein condensates (BECs) form. Room temperature is about 20°C (68°F). At that temperature, gas particles are “moving randomly, each one doing its own thing,” says Dan Stamper-Kurn. He’s a physicist at the University of California, Berkeley. Near absolute zero, some of the particles slow almost to a standstill. They all start vibrating with the same energy, like people dancing the exact same steps. In this state, you can’t tell individual atoms apart.