Module 4:1 Lesson

​Module 4 Energy and Matter

Lesson 1
Particles in Motion

​Linda and Vera purchased fruit pops at the grocery store. The drive home was hot and the fruit pops turned slushy. After a few hours in the freezer, the fruit pops were solid again and ready to eat. What is the relationship between temperature and particle motion?

Multiple Choice

A. Decrease temperature means particles have greater motion.

B. Decreased temperature stops particle motion.

C. Increased temperature means particles have greater motion.

D. Increased Temperature means particles have less motion.

E. Temperature does not affect particle motion.

• A

• B

• C

• D

• E

​Why do some materials feel colder than others?

Imagine the walking along this pier and seeing this ladder on the edge. Which do you think would feel colder, the wood or the metal? For comparison, feel the metal leg of your desk with one hand and the wooden edge of you desk with the other hand. Do they feel like the same temperature? Why would they even feel different? If they are both in the same place and in the same environment, why would they feel different at all?

Imagine that you have been swimming in the lake from the previous picture. ​You climb out of the lake onto the wooden dock. You place a hand on the metal rail and a hand onto the wood. One of the materials feels colder than the other. Why do you think this happened? Use you observation of the materials to make a claim about why some materials feel colder than others and how you can measure the hotness/coldness of the material. Write claim statement on page 8.

​ The sensation of warmth depends on the flow of energy into or out of the skin. Temperature is a measure of average kinetic energy of the particles of a material. The faster the particles move the higher the temperature. Temperature can be measured using a thermometer that operate though thermal expansion.

​What is temperature, and
how is it measured?

​How do particles move?

​A particle is a small unit of matter. Every solid, liquid, and gas is made of particles including the metal and wood blocks from the previous activity. Do you think these particles move when an object is still?

Open Ended

Do you think the temperature of the water affects the motion of the particles? Use reasoning to supports your claim.

​Movement and Collisions

​In the Lab Wait for it, the food coloring moved when the water in the beaker appeared to be completely still. How did this happen? Water particles, like the particles in all liquids, constantly bump and flow past each other in random motion- movement in all directions and at different speeds. The movement and collisions of the water particles push the food coloring particles around, causing the coloring to spread out, or diffuse. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. Diffusion does not happen instantly. Particle diffuse until the concentration is the same throughout the container. When the concentration of food coloring is the same throughout the container, the liquid is one color.

​Take a look at the figure below. Notice that as you move from left to right the particles become more diffused.

​What determines how much energy particles have?

​You know that a rolling ball has energy because it is moving. Particles also move, so they also must have energy. Remember, energy is the ability to cause change. Is there a relationship between how fast a particle moves and the amount of energy it has? Let's investigate.

Open Ended

Use your observations from the video to draw conclusions about this figure. What can you conclude about how adding energy to the liquid on the right will affect the speed of the particles.

​Movement and Energy

​Scientists use diffusion to observe how fast the particles of a substance are moving. The faster the substance diffuses, the faster the particles are moving. In the figure to the Left, Energy was added from the hot plate to the water and dye particles on the right. This added energy increased the motion energy, also called kinetic energy, of the particles. As the the kinetic energy of the particles increased, the speed of the particles increased. The faster particles move, the more kinetic energy they have.

​How to Model Movement

​Motion lines are used to model particle movement in a still image. Since particles travel at different speeds, they need to be represented by different numbers of motion lines. The more motion lines, the faster the particles is moving.

​Read a Scientific Text

​The earliest modern accounts of thermodynamics- the study of heat - can be traced back to the late 1700s through the early 1800s. One of the contributions to thermodynamics was by James Prescott Joule, an English physicist. His ideas on the particle motion of matter were often ridiculed by his peers, but they have continued to withstand the test of time. His contributions to science are recognized by naming the unit for energy the joule (J) The passage below is an excerpt from a lecture Joule gave in 1847. Complete the "Close Reading" on page 15.

​Collect Evidence

​Think about the wood and metal from earlier in Lesson 1. How could the two have energy? Record your evidence (A) in the chant on page 8.

​What happens to a liquid when kinetic energy changes?

​There is no way to see how fast particles are moving. Could you tell if the metal or wood had more energy? One might have felt colder than the other. Is how hot or cold something feels a way to measure how much energy an object has? Let's investigate more!

Investigation

​Energy and Volume

​As the temperature of a material increases, its particles move faster. They collide with each other more often and push each other farther apart. The increase in volume of a material when particle motion increases is known as thermal expansion. The opposite can also occur. A substance can lose kinetic energy and the particles will move slower. As they move slower, they collide with each other less often, which causes the substance to take up less space. This is known as thermal contraction. Thermal contraction happens when particle motion decreases and causes the particles to occupy less volume.

​Energy and Volume

​The property of thermal expansion and contraction can be used to measure temperature. Temperature is the measure of the average kinetic energy of the particles in a material. The temperature of a substance depends on how much kinetic energy the particle that make up the material have. The lower the kinetic energy of the particles, the lower the temperature 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 Scale
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. The Celsisus scale is created with fixed points of 0°C, when water freezes, and 100°C, when water boils. Other scales include the Fahrenheit and Kelvin scale. The Kelvin scale was developed to predict at what temperature particles would stop all motion. This temperature is known as absolute zero of 0 K. If a material reaches 0 K, the particles in that material would not be moving and would no longer have kinetic energy. Scientists have not been able to cool any material to 0 K. Complete the 3-D Thinking

​Collect Evidence: How could the temperature of the wood and metal, from the beginning of the lesson, be measured? Record your evidence (B) on pg 8.
How do particle in gas behave compared to particles in a liquid?
Think about a time when you smelled what was for lunch even though you were not near the cafeteria. The entire school did not smell the lunch at the same time. The people nearby smelled it first. The scent traveled away from the cafeteria over time. You could smell lunch because gas particles move. They move in styraight lines until they collide with something, like another gas particle. These collisions change the speed and direction of particles' movement.
Gas Particles
In gases, particles move at high speeds and have high amounts of kinetic energy. Gases can expand and contract. Just like the dye diffusing in a still beaker of water, being able to smell a scent over a distance is evidence for the movement of particles.

​What evidence is there that particles in a solid move?
Solids, like the wood and metal you observed at the beginning of the lesson, are often described as having a definite shape. They are not fluid like liquids and gases. This means the particles in a solid do not flow past each other. Do particles in a solid move?
Solid Particles
The particles in a solid do not have the same freedom to move around like liquid and gas particles. In a solid, the particles vibrate back and forth in place. Since solid particles only vibrate, they have low amounts of kinetic energy. Expansion and contraction in solids does occur. However it is less noticeable because the particles are holding each other in place.
Collect Evidence: How would models of particles in the wood and metal from the beginning of the lesson, show why one felt colder than the other? Record Evidence (C) on pg 9.

​How does the total amount of a substance affect its energy?
You have learned that particles have kinetic energy due to motion. Kinetic energy can be measured by comparing temperatures of substances. Kinetic Energy is just one part of the total energy that a substance contains.
Energy and Mass
Two substances have the same average kinetic energy by being at the same temperature. When one substance has more particles, that substance has more energy. For example, there are five times as many water particles in 100 grams of water than in 20 grams of water. If the the temperatures of the two water samples are the same, the sample with more mall will contain more total energy. The more particles present, the more total energy present is a substance.
Collect Evidence: How do the masses of the wood and metal, at the beginning of the lesson, affect how much energy they have? Record you evidence (D) on pg 9.

Multiple Choice

Why would these be useful for a road?

• Thermal Expansion

• Thermal Contraction

• Both

Multiple Choice

This is an example of (a) _________.

• temperature scale

• thermal radiation

• random motion

• diffusion