# data[].attributes.attachment_link.title
Which Has More Energy an Iceberg or a Cup of Coffee

# data[].attributes.attachment_link.title
Hair Helps Cool the Body - Biological Strategy - AskNature

# data[].attributes.attachment_link.description
The hair of the Saharan silver ant keeps it cool by efficiently reflecting light and heat energy while also dissipating excess heat.

# data[].attributes.attachment_link.readable_text
Visual, Interactive Simulations for Teaching & Learning Science

Molecular Workbench (MW) is powerful, award-winning software that provides visual, interactive computational experiments for teaching and learning science.

Now thanks to Google's generosity and the power of HTML5, we're bringing this versatile way to experience the science of atoms and molecules to Web browsers.

Try it out →

STEM Interactives

Molecular models are the heart of Next-Generation Molecular Workbench. We've created many models that dynamically illustrate scientific concepts and allow you to interact with molecules or macroscopic phenomena like pendulums (at right) and their environment in various ways.

STEM Activities

Next-Generation Molecular Workbench activities include one or more interactives, plus text, embedded images, video and assessments. There are currently six activities available. We're working on lots more, plus an authoring system that will allow teachers to create their own custom activities.

Try Activities →

Use It... Everywhere

Adding MW interactives to any web page or learning management system is amazingly easy. Simply click an interactive's "Share" link to get the embed code. Learn more in this video.

Partners

The Concord Consortium has partnered with these organizations to provide Next-Generation Molecular Workbench interactives for their online educational courses and activities.

Interested in becoming a partner?
Contact Us

Watch & Learn

Learn More on Our Blog

More information is available on our blog where we get into the nitty-gritty of various aspects of developing Next-Generation Molecular Workbench.

Read more "

Contact Us

Questions? Comments? You can reach us at nextgenmw@concord.org.

You can also subscribe for email updates about Next-Generation Molecular Workbench and our other exciting educational technology projects.

Subscribe for Updates
(Don't worry! We're scientists, not spammers.)

Connect with us online for news about Next-Generation MW and more.

License

This project is © Copyright 2017 by The Concord Consortium and is distributed under the Simplified BSD, MIT or Apache 2.0 licenses.

Classic MW

Classic MW is alive and well, with hundreds of free models you can use right now. These can be used as-is, but there are also hundreds of classroom-tested learning activities based on MW for all levels of science and engineering. See mw.concord.org and workbench.concord.org/database

# data[].attributes.attachment_link.description
Visual, Interactive Simulations for Teaching & Learning Science Molecular Workbench (MW) is powerful, award-winning software that provides visual, interactive computational experiments for teaching and learning science. Now thanks to Google's generosity and the power of HTML5, we're bringing this versatile way to experience the science of atoms and molecules to Web browsers.

# data[].attributes.attachment_link.title
What is Heat? A brief introduction at the particle level.

# data[].attributes.attachment_link.readable_text
Most of us use the word 'heat' to mean something that feels warm, but science defines heat as the flow of energy from a warm object to a cooler object.

Actually, heat energy is all around us - in volcanoes, in icebergs and in your body. All matter contains heat energy.

Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases. Heat energy can be transferred from one object to another. The transfer or flow due to the difference in temperature between the two objects is called heat.

For example, an ice cube has heat energy and so does a glass of lemonade. If you put the ice in the lemonade, the lemonade (which is warmer) will transfer some of its heat energy to the ice. In other words, it will heat up the ice. Eventually, the ice will melt and the lemonade and water from the ice will be the same temperature. This is known as reaching a state of thermal equilibrium.

Moving particles

Matter is all around you. It is everything in the universe - anything that has both mass and volume and takes up space is matter. Matter exists in different physical forms - solids, liquids and gases.

All matter is made of tiny particles called atoms, molecules and ions. These tiny particles are always in motion - either bumping into each other or vibrating back and forth. It is the motion of particles that creates a form of energy called heat (or thermal) energy that is present in all matter.

The particles in solids are tightly packed and can only vibrate. The particles in liquids also vibrate but are able to move around by rolling over each other and sliding around. In gases, the particles move freely with rapid, random motion.

Transferring heat energy - particles in collision

At higher temperatures, particles have more energy. Some of this energy can be transmitted to other particles that are at a lower temperature. For example, in the gas state, when a fast moving particle collides with a slower moving particle, it transfers some of its energy to the slower moving particle, increasing the speed of that particle.

With billions of moving particles colliding into each other, an area of high energy will slowly transfer across the material until thermal equilibrium is reached (the temperature is the same across the material).

Changing states by heat transfer

Faster moving particles 'excite' nearby particles. If heated sufficiently, the movement of particles in a solid increases and overcomes the bonds that hold the particles together. The substance changes its state from a solid to a liquid (melting). If the movement of the particles increases further in the liquid, then a stage is reached where the substance changes into a gas (evaporation).

Three ways of transferring heat energy

All heat energy, including heat generated by fire, is transferred in different ways:

Convection transfers heat energy through gases and liquids. As air is heated, the particles gain heat energy allowing them to move faster and further apart, carrying the heat energy with them. Warm air is less dense than cold air and will rise. Cooler air moves in below to replace the air that has risen. It heats up, rises, and is again replaced by cooler air, creating a circular flow called a convection current. These currents circle and heat the room.

Conduction transfers heat energy in solids. The moving particles of a warm soild material can increase the heat energy of the particles in a cooler solid material by transferring it directly from one particle to the next. Since particles are closer together, solids conduct heat better than liquids or gases.

Radiation is a method of heat transfer that does not require particles to carry the heat energy. Instead, heat is transferred in infrared waves (part of the electromagnetic spectrum). Heat waves radiate out from hot objects in all directions, travelling at the speed of light, until they hit another object. When this happens, the heat energy carried by the waves can be either absorbed or reflected.

Fire illustrates the three different methods of heat transfer. For example, the firebox will heat up due to convection. The air above the fire will be warm due to convection. You can warm your hands near to the flames due to radiant heat transfer.

An effect of heat - expansion

When gases, liquids and solids are heated, they expand. As they cool, they contract or get smaller. The expansion of the gases and liquids is because the particles are moving around very fast when they are heated and are able to move further apart so they take up more room. If the gas or liquid is heated in a closed container, the particles collide with the sides of the container, and this causes pressure. The greater the number of collisions, the greater the pressure.

Sometimes when a house is on fire, the windows will explode outwards. This is because the air in the house has been heated and the excited molecules are moving at high speed around the room. They are pushing against the walls, ceiling, floor and windows. Because the windows are the weakest part of the house structure, they break and burst open, releasing the increased pressure.

# data[].attributes.attachment_link.description
Most of us use the word 'heat' to mean something that feels warm, but science defines heat as the flow of energy from a warm object to a cooler object. Actually, heat energy is all around us - in volcanoes, in icebergs and in your body. All matter contains heat energy.

# data[].attributes.attachment_link.title
Heat Capacity, Specific Heat, and Calorimetry

# data[].attributes.attachment_link.title
GCSE Physics - Conduction, Convection and Radiation

# data[].attributes.attachment_link.readable_text
1. Electrical conductivity

Electric current is the flow of electrons in a wire. In metals, the outer electrons of the atoms belong to a 'cloud' of delocalised electrons. They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metal ions. Normally they move randomly. However, when the wire is connected to a cell, they are pushed away from the negative terminal and drawn to the positive one.

The cloud of electrons drifts through the wire. The drift velocity of the cloud is about 3mms⁻¹. The electrons within the cloud are still moving randomly (at much higher speeds) - rather like a swarm of bees leaving a hive.

2. Thermal conducivity

Metals are good conductors of heat. There are two reasons for this:

Ionic vibrations

The positive metal ions in a metal structure are packed closely together in a symmetrical geometric arrangement. They don't move from their position in the lattice but they are constantly vibrating . If a metal is heated, the positive metal ions vibrate more vigorously. These ions collide with neighbouring ions and make them vibrate more vigorously too. In this way, the energy is passed , or conducted, through the metal.

However, metals are particularly good conductors of heat. In general, they are better than ionic compounds which also have strong bonds. So we need another mechanism to explain their especially good conductivity. It is their free electrons.

Free electrons

The ions in the lattice are vibrating . The ions at the hot end of a piece of metal vibrate more. [Note the electrons have been left out of picture 1.5 to keep it clear.]

Let's look at just a few electrons.

The electrons at the hot end will speed up – they gain kinetic energy from the vigorously vibrating ions.

Some of them will move down to the cooler end and collide with ions that are vibrating less vigorously than those at the hot end.

In these collisions, the electrons will lose kinetic energy and make the ions vibrate more vigorously.

In effect, the electrons have carried the vibrational energy from the hot end to the cold end. And, because they are free to move through the lattice, they are able to do this more quickly than the bonds between the ions in the lattice.

# data[].attributes.attachment_link.title
Steel for many purposes. Thermal and electrical conductivity.

# data[].attributes.attachment_link.description
1. Electrical conductivity Electric current is the flow of electrons in a wire. In metals, the outer electrons of the atoms belong to a 'cloud' of delocalised electrons. They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metal ions.