Peer Teaching 4/Clinic 2

Sara Yerger smy126@psu.edu

Ron Capurso AreC9@psu.edu

Grade 7: Specific Heat at the Beach

Standards Assessed:

PaASST: 3.2.7B – Apply process knowledge to make and interpret observations.

3.5.7C – Describe basic elements of meteorology: Explain the oceans’ impact on local weather and the climate of the region.

NSES: 6.1 – Abilities necessary to do scientific inquiry.

6.2 – Properties and changes of properties in matter.

Instructional Goals:

ü Students should be able to compare the specific heats of water and sand.

ü Students should be able to understand and explain the pressure differences and dynamic between warm and cold air masses.

ü Students should be able to explain how wind patterns are affected by specific heat.

The “Big Idea”:

This lesson explains what specific heat is and demonstrates how specific heat affects heating of different materials and coastal wind patterns. Water has a higher specific heat than the land and therefore retains its temperature throughout a given 24-hour period. This is because of the strong hydrogen bonding property of water. During the day, the land heats up significantly in comparison to the water; the hot air above it then rises, causing a pressure gradient that then pulls the cooler oceanic air in towards the land. The result of this is that there is a local wind created blowing from the ocean toward the land. The reverse occurs during the night, when the land is cooler than the ocean and therefore a local wind is created blowing from the land toward the ocean.

Administrative Concerns:

We must be careful with the students around the temperature probes to ensure that nobody has an accidental injury related to the hot plates.

Materials and Equipment:

ü Computer with Pasco instrument software

ü 2 Pasco temperature probes and adaptors

ü 2 hot plates

ü 2 large beakers

ü Water

ü Dried dirt/sand

ü Whiteboard with 3 different colors of dry erase marker

Setup:

Halfway fill one beaker with sand and one with water. Place each beaker on its own hot plate (the hot plates will be set at the same temperature). Set up the Pasco temperature probes and connect them to the computer. Place one temperature probe in each material, making sure that they do not touch the glass to ensure that we are measuring the proper material.

Engagement (2-3 mins):

First we will ask the students about their experiences at the beach (lake or ocean), i.e. wind and temperature differences that they have felt while at the beach, both during the day and at night. If students do not have or remember such experiences, we will attempt to at least remind them of how hot the sand generally is during the day when compared to the water, because this is a pretty notable experience.

Then students will be asked what they think will happen to the water and sand (i.e. if one will increase in temperature faster than the other or if they will both increase at the same temperature).

Exploration (5-8 mins):

The probes will be setup as described above. The experiment will then be carried out and discussed while the experiment is still occurring. This will include heating the materials and allowing them to cool. The students will be able to examine the graph created by the temperature probes and will note general trends that they see throughout the experiment.

Students will then be asked to hypothesize as to which heats up faster, sand or water. Once they reason through to determine the correct answer, they will then be asked why sand heats up faster than water.

Explanation (4-5 mins):

In order to explain the correct reasoning as to why sand heats up faster than water, we will describe the concept of specific heat, that is, that certain materials retain heat better than others independent of mass. For instance, we will mention that a drop of water has the same specific heat as a lake. Another way to explain this is that less energy is required to heat up a substance that has a higher specific heat. This is because the definition of specific heat is that it is the amount of energy required to raise 1 gram of a substance 1 degree Celsius.

Once students understand specific heat, we will explain the pressure gradient cause by the warm and cold air at the beach. The land heats faster than the ocean and heats the air over it, which then rises, creating the pressure gradient. The colder air from the ocean then swoops in from the ocean to the land, causing a local breeze to be felt in the direction towards the land. At night, this process reverses. The ocean remains roughly the same temperature (which we will emphasize) but the land cools during the evening. The warmer air over the ocean then rises and the colder air from the land rushes out towards the water to replace the missing warm air.

Evaluation (5-6 mins):

In order to ensure that the students understand the lesson, we will have volunteers draw diagrams on the whiteboard to help explain the wind/temperature phenomenon at the beach. We will then probe the students to see if, based on the lesson, they can explain why coastal areas have milder winters and summers than inland (i.e. because the ocean acts as a buffer of temperature).

Elaboration (0+ mins):

We will then ask students if they can connect the concept of specific heat to any other materials that they can think of. We will have a list of different materials such as metals, glass, building materials, etc. and their respective specific heats so that we can have a conversation about whatever they might bring up. We will ask them to think about different objects that they have encountered that were hot (preferably ones on our list of specific heats) so they can hypothesize why certain materials have higher specific heats than others.

Brief Description:

Specific Heat at the Beach

This lesson will explore the concept of specific heat and how it relates to the temperature and wind gradients at the beach caused by the different specific heats of sand and water. Students will use Pasco temperature probes to evaluate temperature changes in both water and sand over a period of time. Students will then apply this knowledge to a coastal setting to explain the wind and temperature patterns observed over a day-night cycle. (Teachers: Ron Capurso and Sara Yerger). [Special needs: Computer with Pasco instrument software, 2 Pasco temperature probes and adaptors, 2 hot plates, 2 large beakers, Water, Dried dirt/sand*, Whiteboard* with 3 different colors of dry erase marker.] Room request: Use of a table for setup and possibly for students to write on.

*Will be provided by teachers