Heat Investigation 5 part 3
EQ. How are changes in matter accompanied by changes in energy? • We have learned a great deal about this but there is more……
Today’s Focus • LEQ 21 Explain how to calculate the energy transferred from the hot water particles and the energy gained by the cold water particles. Discuss their relationship.
What is a calorie? • Open lab manual to page 48 “Calculating heat in Calories A” • Read information
Is there a pattern? • Change in temperature • ΔT=Tfinal – Tinital • Calculate calorie • Mass X ΔT = cal
Cal= • Cal = m X ∆T • Calories = mass X change in Temperature
A Heat Transfer Experiment • Last time we mixed water because we wanted to find out what temperature the final mix would be. • Today, I want to find out how much heat transferred from the hot water to the cold water and how much heat transferred to the cold water during the mixing.
Heat Transfer • Open to Lab Manual page 51 • Information/Data to enter • Columns 1-6
Mass • What is the relationship between mass and volume of water? • 1 mL = 1 cm3 = 1 g Mass volume This is only true for water
Experiment Procedure • Get 50 mL of hot water in one foam cup and 50 mL of cold water in second foam cup • Decide on the mass of hot water and the mass of cold water you will use. (need to be the same) • Measure the water with the graduated cylinders.
Procedure • Record their masses and starting temperatures in the table • Immediately pour the cold water and the hot water in the third foam cup. Put that foam cup into a 500 mL cup for stability • Quickly measure and record the final temperature.
Remember • Act quickly after you record the starting temperature • Immediately mix the samples and take the final temperature • You have 10 minutes! • Clean Up
CLEAN UP • Dump water in sink • Dry all materials completely • Return tray with all materials
RESULTS • What happened when you mixed the hot and cold water? • The mixture reached a temperature that was between the hot and cold water temperatures.
Results- • What caused the kinetic energy to change? • Energy (heat) transfer as a result of particle collisions. Energy transferred from hot water particles to cold water particles until the kinetic energy was the same for all the particles
Results-- • Did energy transfer from the hot water or from the cold water? • Energy transfers from the particles in the hot water. Energy flow is always from higher kinetic energy to lower kinetic energy.
Groups TPS • How many calories were transferred from the hot water? • How many calories were transferred from the cold water? • What does that tell you about energy transfer?
Conservation of Energy • Energy is conserved • The amount of energy in a system is always the same • No energy is ever created, and no energy is ever destroyed. • Energy is transferred.
Energy transfer • From one place to another • From one kind of energy to another kind of energy
Equilibrium • Hot and cold mix and particles collide • Energy transfers from high energy particle to low energy particle (from hot to cold from fast to slow) • Transfer continues until the volume of water is all moving the same speed with same amount of kinetic energy • The number of particles losing energy = the number of particles gaining energy (energy lost = energy gained) • System is balance, no net energy transfer equilibrium is reached temperature holds steady.
Class work • Complete LM page 52-53 • Mid Summative TEST Wednesday