An interesting video that explains what broadcasting is and how it happens. In the previous chapter, we learned that scientists use models when they want to describe things that are difficult to understand. We discussed a model of the atom that helped us imagine what atoms look like. Ask learners to discuss this for a few minutes. Lead the discussion with the following questions: What do we add to the material when we heat it? (Energy.) What do particles do when they receive more energy? (They move faster.) What happens to the spaces between particles when they begin to move faster and collide with each other with more force? (Spaces become larger as the particles move away.) Learners should be encouraged to take notes in discussions. Air particles are pressed into the bag, balloon or tire. The more you blow, the more particles are pushed into the bag, balloon or tire. If there are more particles, there will be more collisions, which means that the pressure will be greater. Gases can be compressed because their particles can be compressed closer to each other. Look at the photo of a diver underwater.
Do you see the tank on his back? He uses this tank to breathe underwater. A diver can stay underwater for almost an hour. How do you think it can get enough air to breathe for an entire hour from a small tank like this? Discuss this with your class. First, let`s look at what happens to particles when they are heated. When water freezes, the particles have larger spaces. (Remind them that this is a unique and unusual property of ice that does not extend to all solids.) Once frozen, the same mass of water now takes on more volume. Water (liquid) is denser than ice. The particles in the water are closer to each other. This means that more of them fit into a certain volume. Container A contains the most particles and C the least. In this chapter, we will review what we know about solids, liquids, and gases.
We will learn more about a scientific model that can be used to describe how particles behave in all three states. This model is called the particulate model of matter and will help us better understand the properties of solids, liquids and gases. Here we go! 4. The particles of a _____ are held in position by strong forces. (5 letters) The second pair of pistons has brown gas in the piston on the left side, but the piston on the right side is completely evacuated. Students are again asked to predict what will happen when the valve is opened. Due to the very high speed of the molecules, they fill the evacuated piston very quickly. Water is unusual in that the solid state is actually less dense than the liquid state, so ice floats on liquid water. This is because there are large gaps between the solid-state particles, making the ice less dense. In the liquid state, the particles do not have fixed positions. They move freely, but they remain close to each other because the forces of attraction between them are quite strong, but not as strong as in solids. Most odors move quickly because their particles mix with the air and enter our nose when we breathe.
We say that the particles diffuse into the air. The table below shows zigzag drawings similar to those before, but you can now see the difference between the random movement of a particle through a liquid and through a gas. It takes much longer for the particle in the liquid to pass from A to B than in the gas. The image of the learner should show a random movement of the perfume with many changes in direction. Show students conventional drawings of particles in solids, liquids, and gases, and ask them if and how fast they think they are moving. You can practically demonstrate this in class with your learners. Have a group of learners stand in the middle of an open space. First, let them simulate the particles in a liquid, so they should be close enough to each other, but still moving. Then, ask the other learners to move through the crowd of learners in the middle. Ask a few learners to do this so that everyone has a chance.
Then ask learners in the middle to simulate particles in a gas by propagating much further and moving much more. They can also cross paths. Other learners now have to move around the crowd, which should now be much easier and faster for them. One piece of cotton soaked in ammonia is placed at one end of a long glass tube, while another soaked in hydrochloric acid (HCl) is placed at the other end. Eventually, a white ring forms where the two gases meet. Both gases have the same temperature and therefore the particles have the same kinetic energy; The ring forms closer to the heavier and therefore slower HCl source. This is predicted by comparing relative molecular weights. With a strip of universal indicator paper in the tube, the diffusion of the gas can be tracked. This is an example of POE where it is useful to draw students` attention to a relevant science before making their prediction, as this is useful for the concept of relative molecular weight (Mr values). Ask learners to discuss this question.
They learned that particles move faster at higher temperatures. How would this affect the spaces between the particles? Most solids and liquids tend to become less dense as heating increases. Learners do not have to draw any conclusions at this stage. However, the question will help to introduce the concepts of contraction and expansion. The problems with the particle model are that it makes several assumptions that are not always the case: to make learners question the possibility of forming new atoms inside the material as an explanation for the expansion phenomenon. Lead them to the law of preservation of mass: matter cannot be produced or destroyed. Materials expand and contract because the particles move away or get closer to each other, not because the number of particles increases or decreases. Can you see how chloride atoms (purple) alternate with sodium atoms (yellow) in a fixed arrangement? Ask learners to briefly discuss what stink bombs are for. You can say that a stink bomb can be used to play a prank on someone. Smelly particles mix with the air and when we breathe air, we feel it. Solids and liquids cannot behave this way.
Their densities remain more or less constant, regardless of the container in which they are placed. This is because their particles are relatively close to each other and have strong forces between them. But what happens when we heat them? We`ve learned that it`s the same as giving them extra energy. How does heating affect particle packaging and density? As the particles swirl, they collide and bounce off each other. They also collide inside the container. The force of the particles hitting the sides of the container causes a phenomenon called gas pressure. The number of bumps (or collisions) depends on the number of gas particles in the container. More particles inside the container mean more collisions, and more collisions mean higher pressure. One possible conclusion is: when the candle wax is heated, energy is added, and the particles begin to vibrate faster and faster until they detach from their solid positions in the solid state and enter the liquid state, resulting in the melting of the wax. When the wax has cooled again, the energy is removed and the particles slow down and move more and more slowly until the forces between them are strong enough to fix the particles in fixed positions in the solid state and the wax solidifies. A fun science lesson and video on the particulate model of matter for children in grades 3, 4 and 5! Matter can change from one state to another. When solids become liquid, the arrangement of the particles changes to be packaged more loosely.
In the activity “Which has the highest density, a solid, liquid or gas?” We compared the densities of different states of the same material. This is a simple comparison because the particles are identical in the different states. By comparing the number of particles in the same volume of each state, we can determine the density of each state. When a gas is pressed into a smaller volume, the particles have less freedom of movement. .