حل درس Energy and matter العلوم منهج انجليزي الصف السادس
Read a Scientific Text
The eariest modem accounts of thermodymüs—the study of heat—can be traced back to the late mos through the earw 18005. One of the contributions to thermodynamics was by James Prescott Joule. an Engish ptysicist HÉ ideas on fie particle motion of matter were often ridiculed by his but they have continued to withstand the test of tirne. His contributions to science are recognized by naming tie unt for energy the joule Jl The passage bebw an excerpt from a lecture Joule gave in 1847
PRIMARY SOURCE
Matter. Livig Force. and
EXPLAIN THE PHENOMENON
YOU climb out of the lake on to the wooden dock You place a hand on metal rail and a hand on wood. One of he materials feels colder than the other. Why do you thrk this happened ? Use observations of the materials to make a claim about some materials feel colder than others ard you can rpaswe hotrpss/ coldness of the material
Some materials feel colder than others
Some materials feel colder because they have a lower temperature than others
COLLECT EVIDENCE as you work throuw„ lessom Then return to these pages to record pur
EVIDENCE
A. What evidence have you to explain the energy of the The two blocks have energy because the particles that make them up are always moving
Moving particles have kinetic energy, as we observed when the dye spread through the
water
B. What e,'dence have pu discovered b explain how the temperature of free blocks be measued
The temperature of the blocks can be measured by using a thermometer. Temperature is a measure Of the average kinetic energy of the particles. We observed how the liquid in a thermometer expands as the temperature increases, which Energy and matter
MORE EVIDENCE
C. What evidence have you discovered to explain how models of the particles in the wood and metal blocks show why one felt colder than the other
As with the metal ball and ring which were heated and cooled, the models of the particles would show particles that have less motion (and therefore less energy) in the metal block than in the wood block
D. What evidence have yu discovered to explain how the masses of the wood and metal blocks affect why one felt colder than the other
A greater mass would mean a larger total energy, which affects how much energy the block has Adding a larger mass of water at 300C caused a larger change in temperature because of the greater amount of energy it had
Ready, Set, Collide
GO ONLINE Watch the video Dye Roce to investigate Mw addng enerw affects partcle movement Record your observatbns belw
Students should record their observations. They should notice that dye in the beaker at the higher temperature diffuses more quickly than dye in the beaker at the cooler temperatur
Use your observations from the video to draw conclusions about the figure below. What can pu conclude about how adding energy to the liqLjd on the right will Mfect the speed of the partkle
Answers may vary. Sample answer : The dye diffused faster in the beaker at the higher temperature. So, the more energy that is added, the faster the particles move. If the particles are moving at a faster speed. they will collide more often and cause the dye particles to diffuse faster around the beaker
Energy and Volum As the temperatjre of a material ncreases. its particles move faster. They colde with each other more often and push each other farther apart The increase in volume of a material when particle motion increaæs is known as thermal exwün. The opposite can also A substance can bse kinetic emrgy and the particles wil move slower. As they move slower. they colfide wit each other les often. which causes the substance to take up less spn. This is known as thermal contraction Thermal happens when particle motion decreaæs and causes the particles to occupy leSs volume
THREE- DIMENSIONAL THINKING
On the right. sketch a diagram to rnodel what the particles on the left would look like if they went through thermal expansion. Circle the model that has more kinetic energy
Students should draw the particles the same size but more spread out with more motion lines to indicate a higher temrature and a larger volume. Studen should circle the model on the right
Energy and Tembrature The proMy of thermal expansion and contraction can be used to Tieasure temperature. Temprature is the measure of the kinetic energy of the particles in a material. The temperature of a substance depends how much kinetic energy the particles that make up the material have. The lower the kinetic energy of the particl, the lower the tenvature of the substance. One way to measure the relative amount of kinetic energy or speed of the particles is by measuring how much the substance expands or contracts
Temperature Scales To compare temperatures you need to use the same temperature scale. A scale uses two fixed points and divides the space between the two points evenly. Celsius scale is created With fixed points of O'C, when water freezes 100'C. when water boils. Other scales irclude Fahrenhei and Kelvin The Celsius scale is used by scientists worldwide Scientists also use the Ketvin scale. The Kelvin scale was devebped to predkt at Miat temperature particles would stop all motion This temperature is known as absolute zero at O K. If a material reaches O K. the particles in that material would not be moving and muld no bnger have kinetk energy. Saentists have mt been able to cool ary material to What is the freezing point of water on each temperature scale? Celsius scale: OOC; Kelvin is qd to 32 dyes
THREE -DIMENSIONAL THINKING
I. Construct an explanatön about the relationship between average particle speed and temperature
As particle speed increases. the temperature increases. As particle speed decreases. the temperature decreases. The relationship is proportional
. What concusbns can you make about kinetic energy and temperature
As the temperature of a substance increases, kinetic energy increases. As the temperature of a substance decreases. kinetic