Homework for Unit Vocab for Unit 6; due: 2. Pg 333 (1-5), Pg 335 (1-4), Pg 337 (1-4), Pg 339 (1-6), No sentences; due:

Transcription

1 Unit 6 Heat

2 Homework for Unit 6 1. Vocab for Unit 6; due: 2. Pg 333 (1-5), Pg 335 (1-4), Pg 337 (1-4), Pg 339 (1-6), No sentences; due: 3. Temperature change activity; due: 4. Heat Transfer Homework; due: 5. Pg 341 (1-4), Pg 343 (1-4), Pg 347 (1-5), Pg 349 (1-4), Pg 351 (1-5) No sentences; due: 6. Pg , matching, Fill in, Multiple Choice, True/false, no sentences; due: 7. Heat Transfer Lab; due: 8. Review packet; due:

3 Vocabulary for Unit 6 Please define the following words. Homework #1 due: Boiling Point calorie Calorie Conduction Conductor Convection Convection Currents Evaporation Fossil Fuels Freezing point Heat Insulator Melting Point Nonrenewable resource Radiation Renewable resource Specific Heat Temperature Thermal Equilibrium Thermal Expansion Vacuum

4 Heat & Temperature Warm-up: - Define matter: Homework #2 due - Define energy: Demo: In front of you I have 3 cups of water. One cup has hot water, one cup has room temperature water and 1 cup has cold water. 1. What down any observations you have as I place drops of food coloring into the water below: 2. What conclusion can you draw between the temperature of the water and how the food coloring spreads out? Heat DOES NOT have or therefore it is NOT. Heat is a form of that is transferred from one object to the next as a result of their differences in temperature. Heat is measured by the temperature change it causes. Remember is made up of tiny, moving particles. As we add the particles move and apart. More heat more heat Heat has the ability to do work, so it is a form of energy. Heat IS NOT temperature! Heat affects the temperature of a substance. Temperature: is the measure of the average energy of the molecules in an object. The the molecules are moving the the temperature of that object.

5 When heat is added the particles move and apart, SO - temperature rises (remember this is an reaction). When heat is lost the particles move and together, SO - temperature drops (remember this is an reaction). Units of Heat calories: (notice it is a LOWER CASE c): The unit representing the amount of need to raise the temperature of g of water by C Amount of water (g) Starting temperature ( C) Ending Temperature ( C) calories Essentially you multiple the amount of water (in grams) by the difference in temperature. Calories (with a CAPITAL C): - This unit is used to represent the amount of energy you get from. 1 C = 1000 c 1C = 1 kc (kilo calorie) 2 C = 2000 c 120 C = 120,000 c this amount of energy can raise the temperature of 120,000 g (120 kg) of water by 1 C Absolute Zero: - The temperature at which all motion of the particles in a substance - Scientists believe this to be the lowest temperature possible, however it has not been reached yet. - Valued at 273 C or 0 K - K Kelvin, no degrees symbol Movement of heat: - Everything in nature moves naturally from high points to points; waterfalls, apples on a tree etc. - Heat flows from areas of temperature to temperature. - When you are holding an ice cube you hand begins to feel. - Your hand has a higher than the ice - Heat flows from you hand to the ice, since heat moves from high to lower - When the heat leaves your hand, your hand feels, because as a result of losing heat the temperature of your hand.

6 Temperature Change Activity (#3) Due: The following experiment was performed. Here is the data that resulted from this activity. 1. One container was filled with cold water from the refrigerator (A), 1 container with water that has been sitting on the lab counter all night (B), and 1 container of hot water from a teakettle (C). 2. The initial temperature of each container of water was recorded. 3. Every 1-minute, the temperature was recorded, in Celsius, in the table below. 4. Complete the remaining data based on the pattern for each cup. 5. Graph your results using a line graph. You need to follow the graphing rules and should have 3 separate lines, one line for each individual cup. 6. Please graph all of the lines in pencil. Trace cup A with a blue colored pencil and Cup C with a red colored pencil. Please make a key on your graph. Time Temp of Cup A ( C) Temp of Cup B ( C) Temp of Cup C ( C) Fill In This data

7 GRAPH: Time (min) Conclusion (complete sentences) 1. According to your graph, which container of water lost the most amount of heat in 10 minutes? 2. Why do you think this container lost the most amount of heat? 3. Which container lost the least amount of heat and why? 4. When were the temperatures the closest? Why do you think this happened? 5. What is thermal equilibrium?

8 Conduction, Convection & Radiation Warm-up: - Define heat: Homework #4 Due: - Define temperature: - How does heat flow? Conduction: - The transfer of through Heat transfer in solids: - Heat moves from areas of temperature to temperatures. - The faster the particles are moving the the temperature. - The fast moving particles into the slower moving particles causing them to up. - When these particles speed up their temperature. Conductor: - A substance that energy (especially heat and electricity) to easily flow through it. - ** All metals are conductors of heat** Insulators: - A substance that does not energy to flow through them. - Examples;,, Conduction Cups: - Heat is transferred when the molecules crash into each other. - The molecules on the hot side of the bar are moving faster, and crash into the molecules near them, which speed up. Those molecules crash into the molecules near them, causing them to speed up. - This is a chain reaction, much like a set of dominoes. - Eventually the cups reach a temperature in between the highest and lowest temperatures, this is called.

9 Convection: - Transfer of heat through and Heat transfer in gases and liquids: - When a gas or liquid is heated the particles out, the volume, and the density. - The warmer, less substance rises, while the cooler, more substance sinks. Convection currents: - The continuous and movements of liquids and gases caused by heat transfer. Demo: I have two containers of water in front of you. One has hot water and one has cold water. 1. I am going to place a test tube with hot water onto the bottom of the cold water container. Please write your observations below: 2. I will now do the opposite with cold water in my test tube and I will place it on top of the hot water container. Please write your observations below: 3. What caused the colored water to move in both experiments? 4. What would happen if, in the first experiment, I held the test tube at the surface of the cold water? 5. What would happen if, in the second experiment, I held the test tube at the bottom of the hot water?

10 Examples of convection: Radiation: - The transfer of heat through a - Vacuum: empty - no air particles Heat from the sun: - The sun is km away. - The heat from the Sun reaches Earth through radiation. This radiation heats up Earth s surface and atmosphere. Examples of radiation:

11 Heat Transfer Homework (#4) Due: In each of the following situations, identify the method of heat transfer taking place (conduction, convection, radiation). More than one process may be occurring. 1. Hot coffee is stirred with a spoon, the spoon gets hot due to.. 2. A chair is placed several feet from a fire in a fireplace. The fireplace has a glass screen. The side of the chair facing the fireplace gets warm because of. 3. A certain type of decorative lamp contains colored liquids. These liquids form globs that break off and rise to the top of the liquid. The globs rise due to. 4. Near the ceiling of a room the air is warmer. The warm air rises because of.. 5. A college student holds the back of his hand near an iron to see if it is hot. Heat is transferred to his hand by 6. A heater is placed under one corner of a water bed mattress. Warm water moves throughout the mattress because of. 7. A certain type of stainless steel cookware has a layer of copper applied to the bottom to help it heat evenly. The copper transfers heat to the pan by.. 8. In a swimming pool, the water near the surface is slightly warmer. The warm water rises because of. 9. One end of a copper rod is placed in a flame of a Bunsen burner. Small pieces of wax placed along the rod melt at progressively larger distance from the flame. Heat is transferred through the rod by 10. A house burns down. On the house across the street, all of the vinyl siding is twisted and warped by the heat. The heat was transferred across the street by.. Identify the method of heat transfer that takes place in each illustration. Some illustrations may show more than one form of heat transfer.

12 Specific Heat and Thermal Expansion Homework #5 Due: Warm-up: - What is conduction? - What is Convection? - What is radiation? Have you ever wondered why your bathroom floor is SO cold compared to your rug, or why you metals legs on a desk are colder than the nonmetal top of you desk? Every substance has its own Specific Heat: this is defined as the amount of heat needed to raise the temperature of 1g of the substance by. This number is based on the ability of the substance to absorb heat. The higher the number the harder it is for that substance to gain heat. If you recall, a calories is the amount of heat needed to raise the temperature of 1g of water by 1 degree Celsius. This is for water, other substances require more or less heat based on the chemical composition of that substance. Water has a very specific heat. Which means that it takes a long time for water to up in the summer and to down in the winter. Sand on the other hand has a specific heat. This is why sand is so on a summer day when you are at the beach, yet feels cold early in the day. Specific Heat of Some Substances Substance Aluminum Copper Gold Iron Lead Water Specific Heat (cal/gram C)

13 As a result of the difference in specific heat and convection currents we have local wind patterns: Thermal Expansion: The of a substance caused by - As we add heat the atoms move and apart. - As a result the increases. - The density - **Please note that the molecules do NOT get bigger!! - Expansion takes place in all three phases of matter Expansion in solids: - Remember: As we add heat the atoms move and apart. As a result the increases. - Sidewalks because they expand on hot days. This is why concrete is set in squares with spaces between them. - Metals that have different specific heats also. When two metals are blended together with different specific heats it allows them to bend at different rates. - Ball and Ring Demo

14 Expansion in liquids: - Remember: As we add heat the atoms move and apart. As a result the increases. - All Liquids expand when heated; including - Remember however, water also when frozen. Expansion in Gases: - Once again: As we add heat the atoms move and apart. As a result the increases. - Example: How do thermometers work? - As the liquid inside the thermometer is heated or cooled the particles either out or move together. - This causes the liquid to (expand) or (contract) within the glass tube. - This continues until the temperatures of the liquid inside the tube and the outside temperature are equal. - This is when the liquid stops rising or falling. - When the temperatures have balances out it is called o Equilibrium.

15 Heat and Our Environment Warm-up: - What is a thermal expansion? Homework #6 Due: - explain how a hot air balloon works: Radiation and the Greenhouse Effect: Earth s atmosphere, like the windows of a greenhouse, allows the sun s visible light to pass through it. But like the windows of a greenhouse, the energy gets trapped inside. This process is called the. Some scientists are concerned that high levels of greenhouse gases (,, and ) in the atmosphere might trap too much energy and make Earth too warm. However, if not for the Greenhouse Effect, Earth would be a, planet.

16 Energy Resources: Renewable resources: Resources that be replaced during our life span. - Solar energy - Wind Energy - Hydro Power (water) - Geothermal Energy: Heat from Earth's interior - yields warmth and power that we can use without polluting the environment. - Biomass: renewable organic material that can be used to produce energy. Examples include aquatic or terrestrial vegetation, residues from forestry or agriculture, animal waste and municipal waste. In other words it is produced from crops, wood, manure, landfill gasses and alcohol fuels. - Ethanol is a prime example of biomass alcohol fuel. Nonrenewable Resources: Resources that be replaced during our lifetime. - - Fossil Fuels: non-renewable resource formed from the of plants and animals, millions upon millions of years ago. - - Electrical Energy from Fossil Fuels: Electricity and other forms of energy can be generating by burning fossil fuels. Nuclear Energy: Generated from radioactive elements such as Uranium. A uranium nuclei is split releasing energy this is called nuclear fission. Uranium is also non-renewable.

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