Coffee pot and cups
Coffee pot and cups

Coffee cup heat losses (optional lab exercise)

Introduction

You should be able to perform this exercise in your kitchen using the equipment usually found there plus a small list of items you might need to buy - see the list of apparatus below. The only hazardous activity is boiling a kettle so please read the risk assessment for boiling a kettle. Download the lab instruction sheet in order perform this lab exercise (at the bottom of this page). It should take about an hour. If you do not have access to a kettle it’s also possible to carry out this experiment using a microwave to heat the water.

Objective

To determine by experiment the overall heat transfer coefficient for a mug, cup or glass of your choice.

Apparatus

You may find the things you need lying round at home, the links below are suggestions if you do not have them to hand. You can also find similar items in many other shops and online sales sites.

You will need:

• a set of digital scales

• a small jug of water (or malt vinegar)

• an electric kettle

• a digital kitchen probe thermometer

• a timer (I used the one in my mobile phone)

• a mug or a glass (I used a mug that held about 0.25 litres of water)

Health and safety risk assessment

All of the lab exercises in this course are optional. Lab exercises aim to apply the theory already covered, enabling a deeper understanding of the material. This lab exercise involves working with water and a kettle. Below are the main risks associated with this lab exercise and measures to reduce these:

• Risk of kettle sides becoming very hot when boiled. Someone could touch the kettle and burn their hands. Kettle should have an insulated handle that does not heat up.

• Risk of hot water being spilt. The kettle must not be carried from kitchen when full of hot water. Extra care should be taken in pouring hot water into cups and, or pots. Cups or pots should be used to move hot water.

• Risk of slipping and falling on spilt water.

• Risk of children or other users pulling hot kettle onto themselves. Children must not be allowed to use the kettle. The kettle should only be used in the kitchen.

• Risk of damage to electric power cable. Check the full length of the cable plus the plug and sockets before plugging in the kettle.

• Risk of overflowing. Boiling water could land on people and scald them, or on socket causing electrocution. Maximum level must be clearly marked in the kettle

How did you do?

Why not take photos of you carrying out your experiment and then post them to our media wall? You can also add a video to the media wall by uploading it to YouTube (or another social media site) and then cutting and pasting the embed code.

Remember to add your name and the experiment you are doing!

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This article is from the free online course:

Energy: Thermodynamics in Everyday Life

University of Liverpool