Do not answer this question directly, but rather use it to introduce the next activity. Ask learners why they think they should punch the holes the same distance from the edge in each type of paper. Creative Commons Attribution License. We use this information to present the correct curriculum and If you have time, you can also test different kinds of materials, such as a plastic shopping bag, aluminium foil or plastic wrap. Since we have no real measure of the energy added to the water, but since we do know that the energy was added at a constant rate, we can use the time that the water was heated as our independent variable. Plot the data on a line graph using the graph paper - each data point must be marked with a small, neat cross. Intensive and Extensive Physical Properties . Boiling point can be used to identify a substance. Coefficient of Area Thermal Expansion All Siyavula textbook content made available on this site is released under the terms of a Let's now analyse and think about the results of the investigation. The boiling point of water at sea level is _______. Possible answers are the metal of cooking pots conducts heat well to cook food and boil water, the metals that make up some heaters also need to conduct heat well. Nitrogen would be a gas at room temperature, because room temperature is higher than the boiling point of nitrogen. Melting point-It is the temperature (in oC or K) at which the substance changes from solid state to liquid state. Just a few sentences are required here. In order to understand and synthesize the impact the materials discussed in this course have on individuals and society, you will need a basic understanding of how scientists, engineers, and sociologists describe materials. Be careful not to drop it or bump it against the bottom or sides of the beaker. We have seen that strength and durability are desirable properties in some materials. What impact do you think this has on the environment? Use the space provided to draw your own table to record your results. 5. ductile: the property of a material that allows it to be drawn out into a wire. Sometimes the cost is purely financial; at other times the cost may be damage to the individual (as in the case of the irresponsible use of medicines and drugs), or to the environment (some examples follow). [1 mark]. Disadvantages are unfavourable features, as can be seen in the images of plastic in the environment. The unknown liquid starts to boil after approximately 40 minutes. For gravity calculation generally water is considered as a reference substance. Learners could be encouraged to imagine carrying a shopping bag filled with heavy items, that would simply fall through a shopping bag that is too weak or thin. The physical properties of a material are those which can be observed without any change of the identity of material. We will learn more about heat transfer later in the year. This chapter looks at key ideas and activities that can be used to help students learn how the properties of materials affects their suitability for different uses. The liquid level will rise when the liquid expands. Chemical properties are discovered by observing chemical reactions. Swirl the ice with a small amount of water for about 20 seconds and then measure the temperature of the ice-water-mixture in the beaker. What do you think will happen when the mixture reaches a temperature of 78°C? It is a property of material which represents that how easily a material can flow in liquid state. Now draw a graph of your experimental data. Repeating an experiment and calculating an average value helps to eliminate errors, or results that arise by chance (or luck). You need to control all other variables so that the only thing you are changing is the type of paper. Furthermore, ethanol and methanol are both extremely flammable and care should be taken when heating them. Coal mining also requires large amounts of water, which reduces the water for surrounding areas. Porosity 3. Is the ice getting warmer or does the temperature remain constant? Water boils at a temperature of 100°C when the air pressure equals 1 atmosphere. The point of this would be to show that the boiling point of water is constant (at constant pressure, of course, so it would make sense to do the extensions concurrently with the prescribed procedure below). TABLE 3.1 Physical Properties of Selected Materials at Room Temperature 5 TABLE 3.2 Physical Properties of Materials, in Descending Order 6 Titanium and aluminum are among the most commonly used metal for aircraft and aerospace applications; 7 FIGURE 3.1 Ratio of maximum yield stress to density for selected metals. Durability 4. Unit of Latent heat in SI system is Joule/Kg. First, let's check if everyone knows that there is a difference between the words heat and temperature. We are going to learn about two new properties of materials, namely boiling point and melting point. Ask your learners what 'room temperature' is and if they can find room temperature on the diagram? Would they like to own one? Spalling resistance 11. Boiling point-It is the temperature (in oC or K) at which the substance changes from liquid state to gaseous state. This will make it a fair test. Physical properties testing expertise includes key physical property characteristics for a wide range of materials. Read the measurement on the thermometer. Say. Water freezes at 0°C. This is also called the freezing point of water. Note: Learners may battle with this question so you can ask them if they think anything can grow or live on these dumps again? Note: Learners should notice that, even though the ice is starting to melt, the temperature remains constant. Do you think plastic is a good choice of material for making a whole cooking pot? While any physical property could be assigned as isotropic or anisotropic, the terms are usually applied to help identify or distinguish materials based on their optical and mechanical properties. The plasticity of a material is its ability to undergo some permanent deformation without … Ice melts at 0°C. They include combustion point, reactivity with acids and toxicity. This classification relates to the dependency of the properties upon the size or extent of the system or object in question. Complete the following table by adding the names of different materials that have the properties listed. Water runoff can also contaminate water supplies. Melting is when a solid changes into a liquid. Learners may be unsure, but you could say that the ethanol is still ethanol, it has not been changed in the process of mixing, so it will most certainly start to boil at 78°C. Mark Obrovac, Department of Chemistry, Dalhousie University, Canada. Coefficient of Volume Thermal Expansion You could let the learners cut the paper into strips of 20 x 5 cm each, or you could do this beforehand to save time. A thermometer is an instrument for measuring temperature. Frost resistance 9. Label the axis, and use degrees Celsius (°C) as units. We learnt in Gr. This is because the layer of fibers is thicker, so more fibers to cling to each other. What do we call the temperature at which the ice melts? We measure temperature with a thermometer. Heat capacity 2. Measure the temperature of the ice-water-mixture every three minutes. We will look more at heating as a transfer of energy next term in Energy and Change. 1. ), How long does it take for the unknown liquid to start boiling? What happened to the temperature of the water when all the ice had melted? Specific gravity 7. Hypothesising, accessing and recalling information, doing investigation, observing, recording information, interpreting information, writing, Activity: Boiling and melting points of other substances, Reading, plotting data on graph, comparing, writing, Activity: Environmental impact of material production, Accessing and recalling information, reading and writing. Remember that when you want to take the temperature, the thermometer must not be touching the sides. The physical properties of a material are those which can be observed without any change of the identity of material. Where, ‘l’ is the initial length of object, ‘Δl’ is the change in length, ‘Δt’ is the change in the temperature. Δt is rise in temperature. This property of materials is called plasticity. Why do you say so? Piezoelectric materials can be used to measure the force of an impact, for example, in the airbag sensor on a car. Freezing point-It is the temperature (in oC or K) at which a liquid changes from liquid to solid state. South Africa is still one of the top gold mining countries in the world. The temperature at which water boils is called the boiling point of water. Suggest three possible uses of flexible materials? The boiling point of water depends on the atmospheric pressure. We say it makes the answer more reliable. This is because you want it to be a fair test - each piece of paper must be tested fairly and equally. Learner-dependent answer. The bigger flame gives more energy to the water per time unit. The change in area of an object due change in temperature is related by “Coefficient of Area thermal expansion”. Learner-dependent answer. The gas bubbles then rise to the surface of the liquid and the liquid is said to boil. Perhaps you have had your temperature taken with a thermometer .A thermometer can be used to find out how hot or cold something is. Before you start, discuss the following questions in your group: Discuss what you know about gases, liquids and solids; the three states of matter. What are the advantages of having a car made of gold? Tell them to bring the biggest pieces they can find. Transmission cables for electricity, electrical wiring, electronic components for computers and other electronic equipment, electrical fencing (to protect property), etc. in order of increasing tearing strength. when coal is burning, greenhouse gases are released which contribute to acid rain formation and the greenhouse effect. Color, density, and thermal conductivity are examples of physical properties. This chapter builds on the chapters about the properties of materials in Gr. For a list of the 10 most serious environmental concerns of the 21st century, visit the website. Make a handle for the yoghurt tub, using the string. Some of the liquid water turned into gas, that is why there were bubbles. A material's property (or material property) is an intensive property of some material, i.e. A material that conducts heat well is said to have a high ________. Perhaps the person was just absent-minded and made a mistake. Below are a number of short sentences. What are some of these? Paper mills use huge amounts of water, and the waste water contains many chemicals and substances which damage the environment. Now draw a blue line at the boiling point of water and also label this line. Specific heat of a material is defined as the amount of heat required to increase the temperature of unit mass of material by 1oC. Q is the amount of heat given to material in Joule. (Tip: Place the marbles very gently into the yoghurt tub or the shock of dropping them in might tear the paper). We call the desirable properties of materials advantages. Have a look at the table that you filled in for part 1 to give you some hints. (Supervisory Control and Data Acquisition), Programmable Logic Controllers (PLCs): Basics, Types & Applications, Diode: Definition, Symbol, and Types of Diodes, Thermistor: Definition, Uses & How They Work, Half Wave Rectifier Circuit Diagram & Working Principle, Lenz’s Law of Electromagnetic Induction: Definition & Formula. Learners could be encouraged to look for signs of these treatments. Bulk density is another important properties of building materials.The bulk density is … AIM: To compare the tearing strengths of different types of paper. The physical properties of engineering materials are as follows. Sometimes, adding substances (such as ethanol) to water can bring the boiling point down (refer to Raoult's Law). Measure the temperature of the water at regular intervals. Physical and Social Properties of Materials . Coefficient of softening 15. We are going to do an investigation to find out! Every process used to produce materials for our benefit has an impact on the environment. Indicate this temperature on your graph. There is air pollution in coal mining and in the use of coal in power stations. How did the temperature of the ice (and water) change over time? The change in length of an object due change in temperature is related by “Coefficient of linear thermal expansion”. Why do you say so? Do you think a golden car would be very strong? (That means from weakest to strongest.). 8 Matter and Materials. You may remember that properties are distinctive characteristics that describe an object or material. It is likely that the teaching of this and the first topic (Mechanical properties of materials) will overlap. Now suppose you start heating the mixture. Write your answer below. a physical property that does not depend on the amount of the material. Since we have to make temperature measurements in the investigation, we are going to first check if everyone knows how temperature is measured. They are mixed but they have not changed into something else. [2 marks], The unknown liquid boils at 65°C. Metals conduct electricity and heat. What can we say about the wool that the jersey is made from in terms of heat conductivity? This is also an extension question as we have not specifically dealt with heat conductivity yet in this grade, but it has been covered in previous grades. Think of some objects which you want to be able to conduct heat well and what material they should be made of. Let's find out. Huge areas of land are used to plant the trees that are then harvested to make pulp and then paper. Diamond mines require huge amounts of diesel which produce greenhouse gases which build up in the atmosphere. Some processes have a look at the moment is the temperature at which the was. 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