Poisson's ratio
Things change shape when you pull them. A rubber band gets thin when you stretch it. This happens to many things. It helps us know how things move. Can you pull a rubber band?
Early Reader · Change the reading level on the articlePhysical Science articles — Page 45
Explore matter, energy, chemistry and the physical laws that help explain everyday life. Choose an article below; its reading controls let you move between the available levels.
2,727 public articles · Page 45 of 57
Polarization density
Some things can hold a charge. When we use a special force, the tiny parts inside move. They do not run away. They just shift a little bit. This helps things work in our world. Can you feel a tiny spark?
Early Reader · Change the reading level on the articlePolarography
A scientist found a new way to test liquids. He used tiny drops of liquid metal. This helps us see what is inside a drink. It is a very smart tool. Do you like to solve mysteries?
Early Reader · Change the reading level on the articlePolaron
Tiny bits move in hard things. These bits push on the parts around them. This makes a little cloud. The cloud moves with the bit. It makes the bit feel heavy. Can you see it move?
Early Reader · Change the reading level on the articlePolyacrylonitrile
Some clothes are made from a special kind of stuff. It helps make warm sweaters and soft socks. It can also make strong parts for big planes. This stuff is very useful. Do you wear clothes like this?
Early Reader · Change the reading level on the articlePolyatomic ion
Tiny bits join to make a group. These groups act like one single thing. They can have a tiny charge. This charge helps make salts. It is very neat to see. Can you find these tiny groups in science?
Early Reader · Change the reading level on the articlePolycarbonate
This is a strong plastic. It is very clear. You can see through it. It can be used for goggles. It is also used for many toys. It helps keep us safe. Do you see this plastic at home?
Early Reader · Change the reading level on the articlePolyethylene glycol
This stuff helps many things. It can help keep old wood safe. It is in some medicines, too. It even helps make big soap bubbles! It is very useful. Do you use it every day?
Early Reader · Change the reading level on the articlePolyethylene terephthalate
This is a special kind of plastic. It is used to make many things. It makes clothes and clear bottles. We can even recycle it to use again. It helps us every day. Do you see this plastic near you?
Early Reader · Change the reading level on the articlePolyisoprene
Some things can stretch and bounce. This comes from tree sap. It can also be made in a lab. We use it to make car tires. It helps us move around. Do you like to bounce?
Early Reader · Change the reading level on the articlePolykarp Kusch
A man named Polykarp Kusch studied how things work. He was a very smart teacher. He found out new things about tiny parts of our world. This work helped many people. He won a big prize for his work. Do you like to…
Early Reader · Change the reading level on the articlePolymer backbone
Many things are made of long chains. These chains act like a backbone. They can be stiff or bendy. Some chains make up your body. They help you grow and live. Can you find these chains in your house?
Early Reader · Change the reading level on the articlePolymerization
Small bits join to make long chains. These chains make many things. They make pipes and bags. This helps us every day. It is like a long line of friends. Do you see things made this way?
Early Reader · Change the reading level on the articlePolymer physics
Some things are made of long chains. These chains can be very wiggly. They move around in water. Heat can change how they act. This helps us make new things. Do you like long chains?
Early Reader · Change the reading level on the articlePoly(methyl methacrylate)
This is a clear plastic. It looks just like glass. But it is much lighter. It does not break easily. We use it for many things. It can even be colorful! Have you seen it before?
Early Reader · Change the reading level on the articlePolyol
Some things are made from special parts. These parts help make foam for beds. They also help make gum. They can be found in food. These parts help us every day. Do you like chewing gum?
Early Reader · Change the reading level on the articlePolyphenol
Many plants make special things. These are found in fruit and tea. They help the plant stay safe. They can even change colors. We find them in food too. Do you like eating fruit?
Early Reader · Change the reading level on the articlePolypropylene glycol
This is a special liquid. It is used to make paintballs. It also helps make paint. We use it in many things. It is safe to use. Can you find it in your house?
Early Reader · Change the reading level on the articlePolystyrene
This is a type of plastic. You can find it in cups. It can also be soft foam. It helps keep things safe in boxes. It is used for many things. Can you find it at home?
Early Reader · Change the reading level on the articlePolysulfane
Some things are made of chains. These chains use tiny bits of sulfur. They can be clear or yellow. They are mostly liquids. These liquids can change very fast. We can find them in labs. Do you like science?
Early Reader · Change the reading level on the articlePolytetrafluoroethylene
Some pans have a special coating. It helps food not stick. This makes cooking easy. It is very slippery. It can even stop ants from climbing. Do you have a pan like this?
Early Reader · Change the reading level on the articlePolyurethane
Some things are made of a special kind of plastic. It can be soft like a sponge. It can also be hard. We use it in many things. It helps make your bed soft. It can even be in your car. Do you see it in your house?
Early Reader · Change the reading level on the articlePolyvinyl acetate
White glue is a sticky stuff. It helps us fix things. You can use it on paper. It works on wood and cloth too. It is safe to use. It helps us make art. Do you like to glue things?
Early Reader · Change the reading level on the articlePolyyne
{ "text": way small things join in long lines. Some plants make these lines. They can be in a carrot. They can even be in space! These lines help plants. They can also be a defense. Do you like carrots? ", "media": […
Early Reader · Change the reading level on the articlePorosity
Some things have tiny holes. These holes are empty spaces. They can hold air or water. This helps rocks hold water. It can even help soil. Can you find something with tiny holes?
Early Reader · Change the reading level on the articlePosition and momentum spaces
We can talk about things in two ways. We can say where a thing is. We can also say how it moves. Both ways tell us the same thing. It is like looking at a toy from two sides. Can you find a toy and move it?
Early Reader · Change the reading level on the articlePosition operator
Tiny things can be in many spots. We use math to find them. It helps us know where they are. This is very cool! Can you find your toy?
Early Reader · Change the reading level on the articlePositronium
Two tiny parts join together. One part is an electron. The other part is a positron. They dance around each other. Soon, they go pop! This makes bright light. Can you imagine tiny things dancing?
Early Reader · Change the reading level on the articlePotassium-40
Some things in our bodies change. This part of a plant or a person is in food. It is even in a banana! It makes a tiny bit of heat. It helps us learn about the Earth. Do you like bananas?
Early Reader · Change the reading level on the articlePotassium acetate
This is a white salt. It helps melt ice on planes. It can even put out fires. Some food uses it too. It helps keep food safe. Do you like to see snow melt?
Early Reader · Change the reading level on the articlePotassium alum
Alum is a special kind of salt. It can look like a clear crystal. People use it to clean water. It also helps make colors stay on cloth. It can even help your skin after you shave. Do you know what else uses salt?
Early Reader · Change the reading level on the articlePotassium bitartrate
Cream of tartar is a white powder. It comes from grapes. We use it to help cakes rise. It also helps whipped cream stay fluffy. It can even help clean metal. Do you like to bake with it?
Early Reader · Change the reading level on the articlePotassium chlorate
This is a white salt. It helps things burn. It is in safety matches. It can even help trees grow fruit. It works very fast. Be careful with it. Can you see the white salt?
Early Reader · Change the reading level on the articlePotassium chloride
This is a white salt. It can be found in the ground. It helps plants grow big. It also helps our bodies stay well. We use it in many ways. Do you like salt on your food?
Early Reader · Change the reading level on the articlePotassium chromate
This is a bright yellow solid. It is used in science labs. It helps people test things. It can be very bad for you. We must be very careful with it. Do you like the color yellow?
Early Reader · Change the reading level on the articlePotassium citrate
This is a white powder. It can be in soft drinks. It helps keep things safe. It can help people feel better. It can even help put out fires. Do you like soft drinks?
Early Reader · Change the reading level on the articlePotassium cyanide
This is a white salt. It looks like sugar. It is used to find gold. It is not safe to touch. It can make people very sick. We must be very careful. Can you stay safe?
Early Reader · Change the reading level on the articlePotassium dichromate
This is a bright orange solid. It looks like tiny crystals. It can change color in a test. This helps people learn new things. It is very pretty to see. Do you like the color orange?
Early Reader · Change the reading level on the articlePotassium ferrocyanide
This is a yellow salt. It looks like small crystals. It helps keep salt from clumping. It can also help plants grow. This salt is very useful. Do you like salt on your food?
Early Reader · Change the reading level on the articlePotassium manganate
This is a green salt. It looks like green crystals. It can change from purple to green. This makes it look like a chameleon. It is a very cool thing to see. Can you find something green today?
Early Reader · Change the reading level on the articlePotassium oxide
This is a pale yellow solid. It is made of two things. It can be used to help plants grow. It reacts fast with water. It is very special. Do you like learning about science?
Early Reader · Change the reading level on the articlePotassium perchlorate
This is a clear salt. It helps things burn fast. We see it in bright fireworks. It makes pretty sparks in the sky. It is very useful. Do you like bright lights?
Early Reader · Change the reading level on the articlePotassium permanganate
This is a purple salt. It can turn water pink. It helps clean things. It can even help keep fruit fresh. It is very strong. Do not eat it. It can hurt you. Have you seen purple water?
Early Reader · Change the reading level on the articlePotassium peroxide
This is a white solid. It is made from air. It can help clean the air. It can also make things white. It reacts fast with water. Be very careful with it. Can you find white things?
Early Reader · Change the reading level on the articlePotassium sulfide
This is a special powder. It is hard to find. It changes when it hits water. This powder helps make bright fireworks. It can make pretty colors in the sky. It is very neat! Have you seen bright fireworks?
Early Reader · Change the reading level on the articlePotassium superoxide
This is a yellow solid. It can help us breathe. It takes bad air and makes good air. It is used in space suits. It is used in big ships too. It helps us stay safe. Can you find something yellow?
Early Reader · Change the reading level on the articlePotential well
Think of a deep valley. It is like a bowl. It holds things inside. A ball stays in the bottom. It cannot roll out. This helps keep things in place. Can you see the valley?
Early Reader · Change the reading level on the articlePotts model
Scientists use a special rule to study things. It helps them see how small bits work together. This rule can help us learn about metals. It can even help us learn about tiny living things. It is very cool! Do you…
Early Reader · Change the reading level on the article