Next Generation Science Standards

Performance Expectation

Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

• Clarification Statement: Examples of experiments could include comparing final water temperatures after different masses of ice melted in the same volume of water with the same initial temperature, the temperature change of samples of different materials with the same mass as they cool or heat in the environment, or the same material with different masses when a specific amount of energy is added.
• Assessment Boundary: Assessment does not include calculating the total amount of thermal energy transferred.

In this performance expectation, we're going to play around with temperature changes. No, you won't be putting a warm burrito on the thermostat to make the air conditioning come on (uh, we mean…who does that?). Students will put their thermometers to task to determine the relationship between a bunch of variables, like mass, type of matter, or energy transferred, and the average kinetic energy of the particles (read: temperature).

Get ready, it's about to get hot in here with these activity ideas:

• Assign each group of students different materials that all have the same mass. Have them heat their materials to the same temperature, then record how much time is required for them to cool down to a predetermined temperature. Discuss the results as a class.
• Have students drop different numbers of ice cubes into several beakers of water. The beakers should have the same amount of water and be the same temperature when the ice is added. Then students will wait a predetermined amount of time and take the temperature of each of the samples of water to determine the effect of the mass of ice on the temperature of the water.
• Provide students with several metal washers. Under supervision, they'll heat the washer for a specific amount of time, either over a flame or in hot water, then place the washer in a beaker of room temperature water. After several minutes, they'll take the temperature of the water. Then repeat the experiment using two washers, then three, and so on until they can clearly see how mass affects the transfer of energy.
• Pour boiling water into three Styrofoam cups. Take the starting temperature of the water. Then place three different objects of equal mass into the three cups. Wait ten minutes, then remove the objects and take the temperature of the water again. Discuss the transfer of energy from the water to the object and how that affected the temperature of the water.

Disciplinary Core Ideas

PS3.A – Definitions of Energy: Temperature is a measure of the average kinetic energy of particles of matter. The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter present.

Students should know that the total energy of a system is the sum of all the types of energy present in that system. To figure out how this is related to the temperature, we have to consider the types, states, and amounts of matter present.

For example, a pot of boiling water is going to have more energy than a block of ice. However, if we ride that block of ice down a hill, it's going to have more energy than if we try to ride the boiling water down the hill. Here's a tip: don't try it.

At this point, students should be on board with the concept of temperature as a measure of kinetic energy. Where they may need a life raft is keeping track of all the other factors present in a system that affect the system's total energy. Working with their peers and experiencing how these different factors influence temperature should keep them from going adrift. Also, don't make them calculate the total amount of thermal energy transferred; otherwise you're likely to have a mutiny.

PS3.B – Conservation of Energy and Energy Transfer: The amount of energy transfer needed to change the temperature of a matter sample by a given amount depends on the nature of the matter, the size of the sample, and the environment.

Changing the temperature of matter may seem as simple as popping it in the microwave. However, as anyone who has reheated leftover Chinese food knows, there are many variables involved in changing temperature.

First, we must consider what type of matter we're transferring energy to. If we attempt to transfer energy to water to raise its temperature to 100 °F, it'll take much longer than if we tried to raise the temperature of the same mass of copper to 100 °F.

Secondly, we have to take into account the size of our stuff. If we're trying to raise the temperature of one milliliter of water to 100 °F, it's going to get there much faster than if we try to raise the temperature of the Statue of Liberty.

Lastly, we have the environment to contend with. It's going to require less energy to heat the Statue of Liberty up in the summer than it is in the winter. The same goes for the water. If you try to heat your pool in the winter, you may as well drain it and refill it with your tears when you get your electric bill.

This concept is fairly intuitive, so students should be able to get the hang of it pretty quickly. They've likely experienced what happens when they hold a cold drink or try to get cookies out of the oven without an oven mitt.

They may just need to put in some extra effort to keep all the variables affecting energy transfer straight. Allow students to work together and they can assign each other to be variable managers so nothing falls through the cracks.

Science and Engineering Practices

Planning and Carrying Out Investigations: Plan an investigation individually and collaboratively, and in the design: identify independent and dependent variables and controls, what tools are needed to do the gathering, how measurements will be recorded, and how many data are needed to support a claim.

Students aren't going to just start randomly poking things with a thermometer. Actually, they probably will at first, but this is where you introduce the idea of a scientific investigation. Students should be able to design an effective investigation both on their own and in a collaborative group.

In their design, they should identify the variables they will be testing and designate a control group. They also need to discuss the type and amount of data that they'll be collecting and what they'll need to collect it. Try to let them down easy when they ask to use the fanciest thermometer they can find, and instead point them in the direction of a sensible thermometer that can be easily replaced when they try to take the temperature of your shredder.

Scientific Knowledge is Based on Empirical Evidence: Science knowledge is based upon logical and conceptual connections between evidence and explanations.

Empirical evidence is, like, the most popular kind of evidence. It's not because it has trendy clothes or a fancy car, though. It's because students get to collect it themselves by performing experiments. Somehow they think this is more exciting than reading about an experiment some old guy did a couple hundred years ago. Go figure.

The evidence they collect isn't just for snorts and snuggles, though. Students should be able to put together what they've observed in their experiments and use that to explain how different variables affect the transfer of energy and the subsequent temperature of an object.

Crosscutting Concepts

Scale, Proportion, and Quantity: Proportional relationships (e.g. speed as the ratio of distance traveled to time taken) among different types of quantities provide information about the magnitude of properties and processes.

For this performance expectation, students explore the relationship between mass, matter, and energy transferred and the amount of time it takes for an object to change in temperature. They should understand the scale upon which these changes happen and these measurements are taken.

For example, they should understand that temperature is a measurement of the average kinetic energy of the particles that make up an object. We're talking atoms here, so this is clearly on a small scale. However, they'll be able to observe on a macroscopic scale the result of changes to the average kinetic energy when they feel an object become warmer or observe a state change.