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6. STEM Stage 2 Activity 11

Stage 2 – STEM Activity 11

Melting mayhem

Description of activity

Students will design a container to slow the melting rate of an ice cube.

This activity will take approximately 90 minutes to:

• explore melting, design and produce an ice cube insulator
• test the insulator
• evaluate the insulator and suggest improvements.

Context

Students will have explored the basic properties of solids, liquids and gases. They will have discussed and observed how solids or liquids are influenced by temperature. Students will have observed the changes made to states of matter through heating and cooling.

Outcomes

Skills

ST2-4WS investigates their questions and predictions by analysing collected data, suggesting explanations for their findings, and communicating and reflecting on the processes undertaken
ST2-5WT applies a design process and uses a range of tools, equipment, materials and techniques to produce solutions that address specific design criteria
MA2-2WM selects and uses appropriate mental or written strategies, or technology, to solve problems
MA2-3WM checks the accuracy of a statement and explains the reasoning used

Knowledge and understanding

ST2-6PW identifies ways heat is produced and that heat moves from one object to another
ST2-12MW identifies that adding or removing heat causes a change of state between solids and liquids
ST2-13MW identifies the physical properties of natural and processed materials, and how these properties influence their use
MA2-11MG measures, records, compares and estimates volumes and capacities using litres, millilitres and cubic centimetres
MA2-13MG reads and records time in one-minute intervals and converts between hours, minutes and seconds

Resources

• Ice cubes, plastic cups, newspaper, cotton, fabric, foam, aluminium foil, plastic wrap, bubble wrap, masking tape, rubber bands
• Timer
• Eye-droppers, measuring syringes, measuring cups.

Work, health and safety

• Check relevant Work, health and safety guidelines.
• Ensure all items brought in from home are clean and child-friendly.

Evidence of work for assessment purposes

• A photograph of the completed container
• A labelled diagram of the design
• A written or oral statement reflecting the effectiveness of the design of the container and its ability to keep the ice cube from melting too quickly.

STEM teaching and learning activities

• Students recall the states of matter (solids, liquids and gases).
• Ask students to think about what actually happens when ice melts (see Additional information, below, for an activity that might help students focus on this issue).
• Brainstorm some human-made items that help keep things cool and from absorbing heat (refrigerator, freezer, esky, etc). Ask the students how they think these items keep things cool.
• Discuss the meaning of insulation.
• Students discuss the characteristics of materials that are insulators.
• Challenge students to design a container that will keep an ice cube from melting for 30 minutes. Show all the materials that students will be able to use.
• Using any and as many of the materials supplied, students design and produce a container that they think will best prevent an ice cube from melting.
• Students must also consider how they can test the effectiveness of their design in terms of extending the life of the ice cube. Students must consider the following:
  • How can an ice block be exposed to exactly the same conditions only without the insulating material?
  • How can the volume of a container be measured?
  • Does the shape of a container affect melting?
  • How can a fair test be established?
• Once their container is ready, students will need to place an ice cube in each container and set the timer for 30 minutes.
• The ice cube in the non-insulated container will be a control by providing a point of comparison.
• During the following 30 minutes, students will think of a method they can use to measure the success of their design, eg the difference in the amount of melting between the two ice cubes. Students should have access to measuring cups, measuring syringes, eye-droppers, etc.
• Students draw a labelled diagram and/or take photos of their containers and the experimental design.
• Once the 30 minutes has passed students will measure the success of their design and record their results.
• Provide students with the opportunity to explain their design to their peers. Students provide answers to the following questions:
  • Was your design successful? Why or why not?
  • How would you change your design to make it more successful?
  • Lead a discussion about the materials used to insulate the container and their effectiveness.
  • Which materials worked best?
  • Describe the properties of these materials.
  • What are the common characteristics of these insulating materials?
• Discuss with the students the reasons why the control ice cube should have melted at a faster rate than the ice cube in the insulated container.

Vocabulary list

Gas – the state in which matter occupies whatever volume is available
Insulate – the act of protecting something by surrounding it with material that reduces or prevents the transmission heat
Liquid – the state in which matter maintains a fixed volume but takes the shape of its container
Melting – the process that causes a substance to change from the solid state to the liquid state
Solid – the state in which matter maintains a fixed volume and shape

Key inquiry questions

What makes ice melt?
Students should understand that an increase in heat energy causes ice to melt. Ice returns to its liquid state when the temperature rises above the freezing point of water (0°C). Ice melts at room temperature because the temperature of the air surrounding the ice cube is higher than the ice cube itself and therefore the ice particles absorb heat energy, are able to move and break away from other ice particles. Thus the ice cube reduces in size and liquid water forms around it.

What actually happens when an ice cube melts?
Some students will think that matter – solids, liquids and gases – is made of particles. When an ice cube is heated, the heat energy increases the movement of the particles. As the particles gain energy, they are able to move away from the other particles in the ice and the ice then turns into liquid water.

How can we keep an ice cube from melting rapidly?
It is important that students understand that ice will melt if the surrounding temperature is warmer than 0°C. Therefore to prevent melting it is important to prevent heat from getting to the ice. Insulation with materials/fabrics, etc can minimise the rate of heat transfer.

Additional information

Many students experience difficulty with visualising and expressing what happens with heat transfer. A useful exercise is to place an ice cube in each student’s hand. Students will notice that the ice cube melts. Ask students how their hand feels. Their hand will feel cold. This is because heat energy is transferred from the hand (making it feel colder) to the ice (providing the particles with sufficient energy to move away from other particles) enabling melting to occur.

Heat is the transfer of energy within or between materials due to differences in their temperatures. Heat transfers from the material with the higher temperature, ie the air in the room, to the material with the lower temperature, ie ice cube. Heat is transferred between materials through the zone of contact between them. The more contact they have, the more heat is transferred per unit of time. Therefore objects of different temperatures with greater surface area in contact with each other will transfer more heat over the same amount of time compared with objects with less contact surface area.

The colour of the materials used will affect heat transfer. The use of light-coloured materials for the container, especially if it is placed in the sun, will affect the rate of the ice melting. Light colours absorb less heat energy and thus the melting of the ice takes longer.

Reflective materials such as foil are also highly beneficial in insulating ice. These containers work on the principle of reflecting the sunlight (energy), without absorbing it. This helps in keeping the contents of the container cool.

Support materials

Teacher resources

• Investigation: Teachers’ TV, whiteboard science
• States of matter: information
• Transfer of heat: a unit of work designed to help students understand the transfer of heat

Student resources

• How is the melting of ice affected by heat?: simulation
• YouTube video: solids, liquids and gases

Diversity of learners

For additional support

• Students work independently, in pairs or in small groups to design and produce their insulated containers.

For extension

• Research the history of refrigeration and how modern refrigerators work to preserve food.
• Investigate the melting rate of ice cubes of different shapes and surface areas.
• Conduct experiments to see which substances melt ice the fastest.

Review

By completing this STEM activity, you have provided your students with the opportunity to explore matter, changes of state and discussed the reasons behind these changes. This study of matter is expanded in Science Stage 4 and will provide evidence for the Particle Theory of Matter. Students have had the opportunity to plan and carry out an investigation, gather data and draw conclusions based on that data. Although much of the investigation was centred on the concept of heat transfer, you have introduced the idea of conservation of mass.

Students have used a variety of materials to design and construct containers to insulate an ice cube. They have used mathematical skills to measure the size of ice cubes (both before and after melting) and the volumes of water collected after melting. Comparison of these values will help students determine the success of their design.