Slurpee Science – salt heat transfer

Slurpee Science – salt heat

Type of resource: Website

Web address https://www.steampoweredfamily.com/activities/sweet-slurpee-science-activity-for-kids/

Language: English

Description

Exploring the principle of salt heat transfer making a slurpee

Scientific concept introduced

Salt heat transfer

Creative and critical thinking

Critical Thinking:
– Prediction
– Analysis
– Explanation

Creative Thinking:
– Curiosity

Mathematical reasoning

– Measuring liquids
– Algebra – directed numbers

Scientific thinking

– Observing
– Questioning
– Measuring
– Predicting
– Analysing
– Drawing conclusions
– Recording

Learning how to learn

– Following guidelines
– Active listening
– Turn taking in groups
– Having patience
– Communication

Additional

– Oral language – listening and following instructions
– Cooking skill of stirring
– Fine motor skills
– Hand-eye coordination
– Collaborative skills of sharing and turn taking

https://www.youtube.com/embed/5XCzuigPuG8?list=PL4VJ0OpU_NAItuz-goQWAsXBHtWriDJCj

Slurpee Science – salt heat

Overall aims

● to enable pupils to explore the chemical reaction between salt and ice
● to develop pupils’ skills in listening and following instructions
● to develop pupils’ cooking skill of stirring
● to develop pupils’ skills in observing and predicting
● to develop pupils’ skills in turn-taking
● to develop pupils’ skills in measuring
● to develop pupils’ skills in recording

Vocabulary – keywords should be understood

Slurpee, ice, water, liquid, juice, salt, freeze, observe, hot, cold, ice cubes, block of ice

Expected learning outcomes (operational aims)

The child will be enabled to:
– identify hot and cold drinks and their characteristics
– follow instructions for making slurpees
– explore how ice and salt react with one another
– practice the skill of stirring
– make observations about how ingredients react and change
– work together in small groups
– orally record their results
– measure out a liquid

STEM skills – to which the learning unit is related to

CORE STEM SKILLS

● Asking questions
● Explaining
● Observing
● Predicting
● Analysing the process of making the slurpee
● Curiosity
● Measuring liquids
● Drawing conclusions
● Recording

ADDITIONAL SKILLS

● Following guidelines

● Active listening
● Having patience
● Communication
● Oral language
● Cooking skills of stirring
● Hand-eye coordination
● Fine-motor skills
● Collaborative skills

Teaching methodologies/activity outline

Teacher Note: This experiment is based on the principle of heat transfer and the effect of salt on ice. You will need a few hours for this experiment, so it’s best to set it up in the morning.

Introduction:

1. Draw 2 columns of the board, labelling one ‘hot’ and the other ‘cold’ and ask pupils to think of as many hot and cold drinks as they can. 2. Then as a class, ask pupils to talk about the following:

– How are hot/cold drinks made? Elicit that heat is applied to make hot drinks e.g. boiling a kettle and cold drinks are kept cool in a fridge.
– When do we most like to have hot/cold drinks? Eliciting that we often like to have hot drinks to heat us up and similarly, we like to have cold drinks to cool us down.

3. Inform pupils that today they’re going to make slurpees. Elicit pupils’ prior knowledge and experience of slurpees, highlighting that they’re made with ice and that ice is water in solid form.

Activity:

Materials: (per group)
– Small plastic cup
– Large bowl
– Spoon
– Ice
– Salt (coarse rock salt works best)
– 1 Carton of juice

Instructions:
Ask pupils working in groups of 5 and taking turns, to do the following:

Part 1

1. Pour the juice into the small plastic cup, filling it half way.
2. Place your plastic cup into the middle of the bowl.
3. Carefully put ice into the bowl, placing it around the cup. It should cover at least ¾ way up the side of the plastic cup.
Sample questions: Can you describe the juice? (Elicit that it’s in liquid form). What do you think will happen to the juice with all the ice around it?

4. Be careful for the next step (making sure not to get any salt into the juice) – sprinkle lots of salt on the ice.
5. Then wait.

Part 2
6. Throughout the day (as instructed by the teacher), take some time to look at your experiment.
Sample questions: Do the ice cubes look the same as they did at the beginning of the experiment? What do they look like now? What is happening to the ice cubes? (The salt is breaking down the ice cubes).

7. Ask pupils to stir the juice gently with the spoon every 30 minutes.
Note – It can take from 1 to 2 hours for the freezing to start but when it does, the mixture needs to be stirred regularly or it’ll form into ice. It’s important to make sure that you scrape the freezing juice off the sides of the plastic cup and mix it altogether.

8. Keep observing your slurpee regularly. You’ll know it’s ready when it becomes
thick. Test to see if it’s thick enough by placing your spoon into it and if you can
stand the spoon up in the slurpee mixture – it’s ready to drink. (Pupils can then
sample their slurpees).

Discuss with pupils:
What is the science behind this?
The salt caused a reaction that pulled heat from around it to melt the ice. This
dropped the temperature around it to below freezing, which then allowed the
drink to go below freezing point. The freezing point is zero degrees Celsius but
it went lower than this (it may go to -4 or -5 degrees Celsius). Then the juice
started to freeze BUT because we remembered to stir and break up the small
ice crystals, the mixture didn’t form a block of ice – and hey presto! We got our
Slurpee!

Conclusion:
As a class, make up a simple song, ‘The Slurpee Song’, which tells the story of
how the slurpees were made.