Keeping it Hot for winter.

     Assessment Task: Lab report 7/3

Tomorrow we will be doing some testing to see what cup best insulates a hot drink for the longest.

This lab report will be assessed officially and due next week.

Today we will discuss what we will do in the lab, write up the introduction, Aim and Hypothesis. Remember, you will be doing the testing as a group but your lab report is an individual task.

Download the correct lab report form here. Please delete the requirement prompt questions for each section.

https://sites.google.com/site/8jsciencematter/chemistry-material-for-a-purpose

Learning Objectives

After this activity, students should be able to:

• Identify materials that are good or poor thermal insulators.
• List modes of heat transfer and identify where conduction and convection occur in an insulated container.
• Describe the effect of insulation thickness on heat transfer.

Summary

Student teams design insulated beverage cups with the challenge to test them to determine which materials (and material thicknesses) work best at insulating hot water to keep it warm for as long as possible. Students test and compare their designs in still air and under a stream of moving air from a house fan.

Engineering Connection

Development of insulated vessels is important in engineering, especially in the fields of mechanical, chemical and biological engineering. What students (and engineers) learn about the design and construction of insulated beverage containers can be applied to the design of insulation for houses, clothing and appliances such as refrigerators and ovens.

Vocabulary/Definitions

conduction:	Heat transfer within or between solid objects.
convection:	Heat transfer into or out of fluids.
heat:	Thermal energy that flows due to a difference in temperature. Heat flows from hot to cold.
heat transfer:	A method by which heat flows (conduction, convection, radiation).
insulation:	A material that slows down heat transfer.
radiation:	Heat transfer due to packets of energy called photons that can travel through many substances, even empty space.

Materials List

Each group needs:

• 4 beverage cups (1 from each lab member) glass, ceramic, aluminium or rigid plastic with tight fitting lids
• other potential insulation materials that students bring from home that they wish to test
• e.g bubble wrap, aluminium, cardboard, wool etc.
• thermometers.
• Keep It Hot! Handout, one per student
• Keep It Hot! Post-Quiz, one per student

To share with the entire class:

• house fan
• hot water in a container with a spout, either from the tap, microwaved or a mix of boiling water and cool tap water

Vocabulary/Definitions

conduction:	Heat transfer within or between solid objects.
convection:	Heat transfer into or out of fluids.
heat:	Thermal energy that flows due to a difference in temperature. Heat flows from hot to cold.
heat transfer:	A method by which heat flows (conduction, convection, radiation).
insulation:	A material that slows down heat transfer.
radiation:	Heat transfer due to packets of energy called photons that can travel through many substances, even empty space.

       Lab Three: The best insulator “Keeping my coffee hot”.  (In class)

Before the Activity

• Invite students to bring in materials from home to test as insulators for their cups
• Students are to bring in their cups and insulators from home and discuss qualities of each cup and insulating device.
• Students to form a hypothesis around which cup will keep the liquid hot for the longest period.
• Prepare a jug(s) of hot water. Keep in mind that the higher the initial temperature of the water in the bottles, the more noticeable the temperature drop will be; however, severe burns may occur if students come in contact, even briefly, with water of greater than 60 ˚C. A 1:1 mixture of boiling water with cool tap water yields approximately this temperature.
• Students to write Introduction, aim, hypothesis, method and materials list for the experiment.

                                                 In the Lab

1. Prepare 4 the cups: with each with different types of insulation attached.
2. Test designs for two 20-minute periods (this is flexible). In the first period, the bottles do not experience forced air movement, so any convection that occurs is natural convection.
3. Measure 200mls of boiling water into each cup and close (Record initial temperature and close quickly)
4. Record temperature change every 5 minutes for each cup. Measuring of temperature must be done very quickly to avoid losing excess heat.
5. In the second period, repeat experiment but place the bottles under airflow provided by a fan in order to see the effect of forced air on heat transfer.
6. Record temperature change every 5 minutes for each cup. Measuring of temperature must be done very quickly to avoid losing.
7. Compare results and write up lab report.