Science Notes 2 (1) PDF

𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐇𝐞𝐚𝐭, 𝐓𝐞𝐦𝐩𝐞𝐫𝐚𝐭𝐮𝐫𝐞, 𝐚𝐧𝐝 𝐂𝐨𝐧𝐝𝐮𝐜𝐭𝐢𝐨𝐧 1. Adding energy (heating) atoms and molecules increases their motion, resulting in an increase in temperature. 2. Removing energy (cooling) atoms and molecules decreases their motion, resulting in a decrease in temperature. 3. Energy can be added...

𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐇𝐞𝐚𝐭, 𝐓𝐞𝐦𝐩𝐞𝐫𝐚𝐭𝐮𝐫𝐞, 𝐚𝐧𝐝 𝐂𝐨𝐧𝐝𝐮𝐜𝐭𝐢𝐨𝐧 1. Adding energy (heating) atoms and molecules increases their motion, resulting in an increase in temperature. 2. Removing energy (cooling) atoms and molecules decreases their motion, resulting in a decrease in temperature. 3. Energy can be added or removed from a substance through a process called conduction. 4. In conduction, faster-moving molecules contact slower-moving molecules and transfer energy to them. 5. During conduction the slower-moving molecules speed up and the faster-moving molecules slow down. 6. Temperature is a measure of the average kinetic energy of the atoms or molecules of a substance. 7. Heat is the energy transferred from a substance at a higher temperature to a substance at a lower temperature. 8. Some materials are better conductors of heat than others. FREEZING WATER EXPANDS!!!! If it’s in a glass it won't expand sideways, only up. Roads develop potholes during cold winters. When water gets in small cracks in the road and freezes, it expands and breaks the asphalt. When this continues to happen below the surface, it eventually forms a pothole. When water freezes, the water molecules have slowed down enough that their attractions arrange them into fixed positions. Water molecules freeze in a hexagonal pattern and the molecules are further apart than they were in liquid water. The change of state where a gas changes directly to a solid without becoming a liquid is called deposition. Really old ice cubes left in the freezer for a long time (for example, a year) the ice cubes will shrink. That’s because they’re evaporating. Under some conditions a gas can turn directly to a solid without going through the liquid phase. This process is called deposition. Some of the ice that formed on the outside of the can may have been a result of deposition. The frost that forms on the ground, windows, or grass in winter is formed by deposition. The temperature at which a substance freezes is called its freezing point. The freezing point of water is 0°C (32°F). Corn oil and isopropyl alcohol have lower freezing points than water. This means that they need to be cooled to lower temperatures to make them freeze. 𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐂𝐡𝐚𝐧𝐠𝐞𝐬 𝐨𝐟 𝐒𝐭𝐚𝐭𝐞: 𝐅𝐫𝐞𝐞𝐳𝐢𝐧𝐠 1. Freezing is the process that causes a substance to change from a liquid to a solid. 2. Freezing occurs when the molecules of a liquid slow down enough that their attractions cause them to arrange themselves into fixed positions as a solid. Ice placed in water will melt faster than ice in air. Since the water and the air are both at room temperature, it may not be obvious at first why this is true. There are so many more molecules of water that contact the ice, so the transfer of heat to the ice is much faster in the water than in the air. The molecules of the air are more spread out and there is much less contact between them and the ice. Therefore, the transfer of heat from air to ice is slower. Another way of saying this is that water is a much better conductor of heat than air. The liquid water takes up less space. On the molecular level, the water molecules in liquid water are closer together than they are in solid water As the ice melts, the orderly arrangement collapses and the water molecules move past each other and actually get closer together as liquid water. This is an unusual characteristic of water. In most substances, the atoms or molecules in the solid state are closer together than the atoms or molecules in the liquid state. Dry ice changes from a solid to carbon dioxide gas, which is invisible. In ice, the arrangement of water molecules creates extra space. The water molecules freeze in a hexagonal pattern and the molecules are further apart than they were in liquid water. 𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐂𝐡𝐚𝐧𝐠𝐢𝐧𝐠 𝐒𝐭𝐚𝐭𝐞: 𝐌𝐞𝐥𝐭𝐢𝐧𝐠 1. Melting is a process that causes a substance to change from a solid to a liquid. 2. Melting occurs when the molecules of a solid speed up enough that the motion overcomes the attractions so that the molecules can move past each other as a liquid. 𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐂𝐡𝐚𝐧𝐠𝐞𝐬 𝐨𝐟 𝐒𝐭𝐚𝐭𝐞: Condensation 1. Condensation is the process in which molecules of a gas slow down, come together, and form a liquid. 2. When gas molecules transfer their energy to something cooler, they slow down and their attractions cause them to bond to become a liquid. 3. Making water vapor colder increases the rate of condensation. 4. Increasing the concentration of water vapor in the air increases the rate of condensation. 𝐊𝐞𝐲 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 - 𝐂𝐡𝐚𝐧𝐠𝐞𝐬 𝐨𝐟 𝐒𝐭𝐚𝐭𝐞: 𝐄𝐯𝐚𝐩𝐨𝐫𝐚𝐭𝐢𝐨𝐧 1. Evaporation occurs when molecules in a liquid gain enough energy that they overcome attractions from other molecules and break away to become a gas. 2. Adding energy increases the rate of evaporation. 3. To conduct a valid experiment, variables need to be identified and controlled. Chloe’s Notes: Energy pervades the entire universe. Everything is energy, just a different form. Gravity is the weakest force in the universe. The universe is permeated with energy. Two categories of main energy, Kinetic and potential. Potential energy is something that has the POTENTIAL to have energy. Kinetic energy is a form of energy that an object or a particle has by reason of its motion. Energy is the ability to do work. Humans are currently trying to figure out other ways to renew energy. Niagara Falls moves a giant turbine with a magnet with wires to give us energy. Energy cannot be created or destroyed - it can only be converted from one form to another. Examples of energy being released into the environment include: ​ A lightbulb: electrical energy produces heat energy that is released ​ A washing machine: electrical energy produces heat and sound energy that is released Ellie’s Notes: FORMS OF ENERGY Everything has energy. Energy can’t be created or destroyed. Energy can be potential energy (has potential to have energy) or kinetic energy (actual energy in motion). Energy can be transferred. -​ Chemical energy. Energy in objects. Wood has energy. When we burn wood we release its energy. -​ Motion energy are things that are moving -​ Thermal energy is heat. -​ Electrical energy is light, heat, or sounds made by electricity. SOURCES OF ENERGY -​ Biomass is energy from burning plants or garbage -​ Geothermal energy is heat energy from the Earth’s mantle and core -​ Hydroelectricity is energy from moving water -​ Solar energy is energy from the sun -​ Wind electricity is energy from wind Sources of energy can be renewable (“recharge” themselves). Most aren’t QUESTIONS Throwing at something, motion energy Water falling, Hydroelectricity Computer plug, electrical energy