Who said matter is made of particles that are in constant motion

Due to the conservation of energy, if one particle loses energy, another gains energy. There can be a loss of energy by, for example, thermal radiation, but the sun and radioactive decay keep things warm here on Earth. Yet even if a substance were cooled to absolute zero, its particles would still be moving.

There are also particles in space, moving at high speeds. They just keep going because there is practically nothing to slow them down. They can continue for billions of light years.

With an increase in temperature, the particles gain kinetic energy and move faster. The actual average speed of the particles depends on their mass as well as the temperature — heavier particles move more slowly than lighter ones at the same temperature. The oxygen and nitrogen molecules in air at normal room temperature are moving rapidly at between to metres per second.

Unlike collisions between macroscopic objects, collisions between particles are perfectly elastic with no loss of kinetic energy.

This is very different to most other collisions where some kinetic energy is transformed into other forms such as heat and sound. It is the perfectly elastic nature of the collisions that enables the gas particles to continue rebounding after each collision with no loss of speed. Particles are still subject to gravity and hit the bottom of a container with greater force than the top, thus giving gases weight.

If the vertical motion of gas molecules did not slow under gravity, the atmosphere would have long since escaped from the Earth. In liquids, particles are quite close together and move with random motion throughout the container.

Particles move rapidly in all directions but collide with each other more frequently than in gases due to shorter distances between particles. With an increase in temperature, the particles move faster as they gain kinetic energy, resulting in increased collision rates and an increased rate of diffusion.

In a solid, the particles pack together as tightly as possible in a neat and ordered arrangement. The particles are held together too strongly to allow movement from place to place but the particles do vibrate about their position in the structure. With an increase in temperature, the particles gain kinetic energy and vibrate faster and more strongly.

The attractive force in solids need not be stronger than in liquids or gases. For example the forces between solid helium particles at degrees C are still very weak. By comparison, the forces between iron vapour particles requires very high temperatures are very strong. If you compare different substances that are at the same temperature, then the average kinetic energy of the particles will be the same i. Attractive forces don't get weaker when a substance moves from the solid to the liquid to the gas state, rather the kinetic energy of the particles increases implying faster motion , allowing them to overcome the attractive forces.

Explore the relationships between ideas about movement of particles in the Concept Development Maps - Chemical Reactions, States of Matter. While the material attempts to explain some changes of state at the molecular level, most of the explanations are not made in terms of changes in the arrangement, interaction, and motion of atoms and molecules.

Chapter 3 includes an explanation of phase changes in general as well as explanations of specific phenomena related to melting, freezing, evaporation, boiling, and condensation pp. Most of these explanations refer only to the flow of energy into or away from a material such as those for freezing and condensation [pp. Finally, a phase-change diagram shows colored dots close together and arranged regularly in a solid, less so in a liquid, and even less so in a gas, but there is nothing in the accompanying text that notes what the colored dots represent p.

Building a Case. In general, students do not encounter these ideas in progressively higher levels of sophistication. On the contrary, ideas are introduced without preparation or are merely repeated rather than being revisited explicitly or extended clearly to new contexts. For example, Chapter 3: Physical and Chemical Changes relies on the concepts of heat, energy, and temperature; however, these concepts are not taught until chapters 16 and Furthermore, the material does not provide tasks, questions, or text that tie together clearly the experiences that students have with the same idea.

When elements and compounds are introduced in chapter 4, the text merely states that atoms are the smallest particles of elements p. No attempt is made to connect separate statements about the same idea or to help students see that these particles are the same particles referred to in chapter 3 on the states of matter. Instead, it defines an atom as the smallest part of an element. The material makes some conceptual connections among ideas; however, the connections are often implicit, brief, and difficult to locate.

For example, on page s, an opportunity is missed to connect chemical reactions explicitly to the constant motion of molecules. Later, though, the idea that increased temperature means increased molecular motion is connected explicitly and adequately to the fact that an increase in temperature generally increases the rate of reaction p. However, the theme of scale and structure is not described, nor is it specified how the idea is linked to that particular theme. Beyond Literacy. This textbook goes far beyond the key idea that all matter is made up of atoms and includes content that is more appropriate for high school students, and even goes beyond the scope of science literacy ideas in Benchmarks for Science Literacy American Association for the Advancement of Science, and National Science Education Standards National Research Council, Identified errors occur most frequently in drawings and other diagrams.

They take the form of representations that are likely to either give rise to or reinforce misconceptions commonly held by students. Following are physical science examples of the kinds of misleading illustrative materials of most concern to the evaluation teams:. Diagrams and drawings that show atoms or molecules of solids, liquids, and gases in colored backgrounds for example, water molecules inside blue drop shapes and that thereby can initiate or reinforce the misconception that particles are contained in solids, liquids, and gases, in contrast to the correct idea that substances consist of particles with empty space between particles.

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What term is used to describe splitting a large atomic nucleus into two smaller ones. Q: Who said matter is made of particles that are in constant motion is predictable?