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November 19 Q2 - pg. . Daily Goal: We will analyze materials to decide which will be the best conductor and which will be the best insulator. Homework : Science Fair Rough Layout, Engineering Challenge Science Starter: How does conduction work?
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November 19Q2 - pg. • Daily Goal: We will analyze materials to decide which will be the best conductor and which will be the best insulator. • Homework:Science Fair Rough Layout, Engineering Challenge Science Starter: • How does conduction work? • What happens to particles as they get hotter? • Do substances take up more space when they are hotter or colder? • Why do you think a tent is colder than a wooden house?
Table of Contents – Quarter Two Parts of the Ear and Test Preparation Q2 - PG. 1 Physical and Chemical Changes Intro Q2 – PG. 3 Physical and Chemical Properties Q2 – PG. 5 Density and Intro to Heat Transfer Q2 – PG. 7 Heat Transfer – Particle Movement Q2 – PG. 9 Conductors and Insulators Q2 – PG. 13
Touch the wooden part of your desk • In your notebook, write down in full sentence what you notice about the temperature of your desk.
Touch the Metal Leg of your chair • In your notebook, write down in a full sentence what you notice about the temperature of the metal. • How does it compare to the temperature of the wood?
Copy this chart into your notebook • Cool to the touch:Warm to the touch:
I will pass around different materials: • Plastic Bag • Cloth • Coat • Glass beaker • In your notebook, write each of the materials in the appropriate box (cool to the touch, warm to the touch). • After you have finished, answer this question: • What similarities do you see in the lists you made?
Write a hypothesis: • Use your observations and the similarities that you identified to formulate a hypothesis. Write your hypothesis in your notebook. • How do you think the type of material is related to its ability to transfer heat?
Think – Pair – share: • Think about what happens when you walk barefoot in a room with tile compared to when you walk barefoot in a room with carpet. • Use what you just learned to explain why it feels different.
Definitions • Insulator: Object that blocks the transfer of heat (It keeps heat in or out.) • Conductor: Object that transfers heat easily
remember! Heat conduction (or thermal conduction) is the transfer of heat energy through matter, from a region of highertemperature to a region of lower temperature.
***Write this down*** Conductor – an object that transfers heat energy easily Metals are usually good conductors. When one end of something metal gets hot, usually the other end gets hot very quickly. Think about the handle of a metal pot or the edges of a metal pan. Those get too hot to touch soon after you turn on a stove!
***Write this down*** Insulator – an object that blocks the transfer of heat energy Wood, paper, plastic and Styrofoam are good insulators. Think about a Styrofoam cup. It has tiny pockets of air inside of the material, so it will not transfer energy easily through conduction. That is why it is used to keep cold drinks cold and hot drinks hot.
Energy is always being transferred between hot and cold objects. Sometimes we need to slow down the transfer of energy. Think about what would happen if energy was always transferred quickly. How could we keep our school warm in cold weather? We need insulators! Insulators keep hot things hot and cold things cold. The insulation of a building keeps the warm air inside and it keeps the cold air out by trapping the energy.
Examples in Real life: A wool sweater traps air against your body. Air and wool are both poor conductors, so you lose heat very slowly and stay warm longer. A thermos has a layer of empty space (a vacuum) in between the inside and outside layer of material. This stops conduction from happening between the two layers. Also, the outside is made of a shiny material that reflects light (and radiation).
Natural insulation Polar bears stay warm in very cold temperatures because they have specialized hairs called guard hairs. The guard hairs are hollow and have air in the middle. The air slows down conduction and keep the polar bear warmer for longer.
Experiment Data Analysis Ms. Jones is tired of going to high school football games and sitting on cold metal bleachers. She decides to test two different wraps to see which will keep her seat the warmest. On one seat she ties a cotton-stuffed pillow. On the other, she ties a wool blanket. Over a period of 5 hours, she measures the temperature of her seat.
Questions to Ask • What is constant? • What is being tested? • What is different between the two containers?
Questions to Ask • How do the numbers change? • How quickly do they change? • How much do they change by? • Which materials are conductors? How do you know? • Which materials are insulators? How do you know?
Experiment #2 • In order to test the conductivity and insulating properties of dirt, air, and water, students filled a tin can with each substance, as follows:
Experiment #3 Students were challenged by their teacher to keep hot water in a glass beaker as hot as possible for a period of 15 minutes. The students used three different beakers, one wrapped in Styrofoam, one wrapped in cardboard, and one wrapped in foil. The results of their experiment are in the table below:
