separating solutions experiment

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Research Briefing
• Published: 02 September 2024

Gold nugget formation from piezoelectric quartz

Nature Geoscience ( 2024 ) Cite this article

1 Altmetric

Metrics details

• Economic geology
• Geochemistry

Deformation experiments and piezoelectric modelling show that the electric charge generated by quartz crystals is capable of depositing dissolved gold. These results suggest that the piezoelectric activity of quartz might drive gold nugget formation from hydrothermal solutions in earthquake settings.

This is a preview of subscription content, access via your institution

Access options

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

24,99 € / 30 days

cancel any time

Subscribe to this journal

Receive 12 print issues and online access

251,40 € per year

only 20,95 € per issue

Buy this article

• Purchase on SpringerLink
• Instant access to full article PDF

Prices may be subject to local taxes which are calculated during checkout

Williams-Jones, A. E., Bowell, R. J. & Migdisov, A. A. Gold in solution. Elements 5 , 281–287 (2009). A review article that discusses gold transport and deposition in Earth systems.

Article   CAS   Google Scholar  

Sibson, R. H., Moore, J. M. & Rankin, A. H. Seismic pumping—a hydrothermal fluid transport mechanism. J. Geol. Soc. 131 , 653–659 (1975). This paper presents the seismic-pumping earthquake model for orogenic deposit formation.

Article   Google Scholar  

Curie, J. & Curie, P. Développement par compression de l’électricité polaire dans les 333 Cristaux hémièdres à faces inclinées. Bull. Minéral. 3 , 90–93 (1880). This paper reports the first documentation of piezoelectricity.

Google Scholar  

Finkelstein, D. & Powell, J. Earthquake lightning. Nature 228 , 759–760 (1970). An article discussing earthquake lightning.

Wang, J.-H. Piezoelectricity as a mechanism on generation of electromagnetic precursors before earthquakes. Geophys. J. Int. 224 , 682–700 (2020). An article that discusses piezoelectricity producing electromagnetic signals.

Download references

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This is a summary of: Voisey, C. R. et al. Gold nugget formation from earthquake-induced piezoelectricity in quartz. Nat. Geosci . https://doi.org/10.1038/s41561-024-01514-1 (2024).

Rights and permissions

Reprints and permissions

About this article

Cite this article.

Gold nugget formation from piezoelectric quartz. Nat. Geosci. (2024). https://doi.org/10.1038/s41561-024-01529-8

Download citation

Published : 02 September 2024

DOI : https://doi.org/10.1038/s41561-024-01529-8

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

• Skip to primary navigation
• Skip to main content
• Skip to primary sidebar

• FREE Experiments
• Kitchen Science
• Climate Change
• Egg Experiments
• Fairy Tale Science
• Edible Science
• Human Health
• Inspirational Women
• Forces and Motion
• Science Fair Projects
• STEM Challenges
• Science Sparks Books
• Contact Science Sparks
• Science Resources for Home and School

Mixtures for Kids

September 2, 2020 By Emma Vanstone 5 Comments

What is a Mixture?

A mixture is a substance in which two or more substances are mixed but not chemically joined together, meaning that a chemical reaction has not taken place.

Mixtures can be easily separated and the substances in the mixture keep their original properties.

Imagine mixing skittles and full size marshmallows, the individual components (skittles and marshmallows) could easily be separated using a filter and each component of the mixture ( skittles and marshmallow ) doesn’t change. 

How to make a mixture

You can make your own mixtures with items from around the house.

1. Firstly try to make a mixture of toys.

2. This time use cereals or sweets.

What is a solution?

A solution is made when a solid (which we call a solute) dissolves into a liquid (that we call the solvent) One example of a solution is salt dissolved in water. The salt and water can be separated again by evaporation ( the water will evaporate if left in a hot place leaving he salt behind ).

Investigation

Aim : To test out these three mixtures to see which form solutions and which don’t

• Salt and Water
• Sugar and Water
• Sand and Water

Results Table

You should find that both salt and water and sugar and water dissolve and form solutions and that sand sinks to bottom!

How do you separate mixtures?

Can you separate the components out of the mixture again? Hint – to separate the sand from water you could use a sieve. This is possible as the sand is insoluble ( doesn’t dissolve in water ).

Salt and sugar are soluble ( dissolve in water ) and can be separated by evaporation.

Another way to separate a mixture is by using a process called chromatography .

Challenge – how would you separate rock salt and water?

Rock salt is a mixture of salt and sand and is often spread on roads in winter to stop cars skidding.

Stage 1 – Grinding

First the rock salt should be ground using a pestle and mortar.

Stage 2- Dissolving

The ground rock salt should be dissolved in a beaker and stirred thoroughly.

Stage 3 – Filtering

The solution of water and rock salt should be passed through the filter paper where the sand ( which will not have dissolved in the water ) will collect.

Salt does dissolve in water and so will pass through the filter paper.

Stage 4 – Evaporating

To separate the salt from the water the water needs to be evaporated off, either by leaving the salty solution in the sunshine or placing under a heat source.

The salt will form as crystals – this process is called crystallisation .

Last Updated on May 24, 2021 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

July 18, 2012 at 2:17 pm

Those are great educational play activities. I love your ideas for teaching the difference between a mixture and a solution in a meaningful way. Families can try out your mixtures and solutions and then come up with their own too. Thank you for sharing this on Artsy Play Wednesday on Capri + 3.

: 0 ) Theresa

July 23, 2012 at 6:50 am

Thank you. I’m glad you like it. x

October 08, 2020 at 12:08 pm

This helps me to keep my child busy and I love it So well done!

February 24, 2021 at 8:44 pm

Simple, fun, and accurate!! Thanks from myself and my e-schooled granddaughter 😉

October 08, 2021 at 3:29 pm

I´m a middle school student and and it has helped me understand things better

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Choose an Account to Log In

Notifications

Science project, separating mixtures.

Grade Level: 3rd - 5th; Type: Physical Science

Objective :

To explore the different properties of matter than enable mixtures to be separated. To demonstrate the separation of mixtures through filtration and evaporation.  

Research Questions:

• How can mixtures be separated?
• Why are the physical properties of matter important in separating mixtures?
• What occurs during filtration of a mixture?
• What occurs during evaporation of a mixture?      

Different types of matter can be combined to form mixtures. Thanks to the physical properties of matter such as size, shape, and density, mixtures can also be separated back into their different kinds of matter. One way mixtures can be separated is through filtration. Filtration is the passing of matter through a filter to separate larger particles. Another way mixtures can be separated is through evaporation. Evaporation is the process where the liquid in a mixture changes to a gas leaving other solid particles behind.

• Coffee filters
• Straw                                          

Experimental Procedure :

• Stir a spoonful of sand into a half a cup of warm water. What happens to the sand? Record your observations.
• In another cup, stir a spoonful of salt into a half a cup of warm water. What happens to the salt? Record your observations.
• Stick the straw into the salt water mixture. Take a small sip. What does it taste like? What does this prove about the salt?
• Look at the sand mixture and the salt mixture. How are the mixtures different? Record your observations. Do you think the mixtures can be separated?
• Place a coffee filter over one of the empty cups. Carefully and slowly pour the sand mixture into the filter. Record your observations. What happens to the water and the sand?
• Try the same filtering method with the sand water. What happened? Taste the “filtered” salt water again with a straw. What do you notice about the taste?
• Pour a small amount of salt water into another cup. Set it on a windowsill and observe it every day for a few days. Record your observations. After the water is gone, what is left behind? 

Terms/Concepts: Matter; Mixture; Particles; Filtration; Evaporation

References:

a.     http://answers.askkids.com/Fun_Science/how_to_separate_mixtures b.     http://chemistry.about.com/cs/5/f/bldistillation.htm

Chemistry for Kids

Separating mixtures.

• To separate liquid solutions where the substances have similar boiling points, a more complex version of distillation is used called fractional distillation.
• Painting uses the separation process of evaporation. The wet paint is a mixture of color pigment and a solvent. When the solvent dries and evaporates, only the color pigment is left.
• The separation process of winnowing was used in ancient cultures to separate the grain from the chaff. They would throw the mixture into the air and the wind would blow away the lighter chaff, leaving the heavier grain.
• High speed centrifuges can spin up to 30,000 times a minute.
• Many separation processes are occurring constantly in nature.

Your browser is not supported

Sorry but it looks as if your browser is out of date. To get the best experience using our site we recommend that you upgrade or switch browsers.

Find a solution

• Skip to main content
• Skip to navigation

• Back to parent navigation item
• Primary teacher
• Secondary/FE teacher
• Early career or student teacher
• Higher education
• Curriculum support
• Literacy in science teaching
• Periodic table
• Interactive periodic table
• Climate change and sustainability
• Resources shop
• Collections
• Remote teaching support
• Starters for ten
• Screen experiments
• Assessment for learning
• Microscale chemistry
• Faces of chemistry
• Classic chemistry experiments
• Nuffield practical collection
• Anecdotes for chemistry teachers
• On this day in chemistry
• Global experiments
• PhET interactive simulations
• Chemistry vignettes
• Context and problem based learning
• Journal of the month
• Chemistry and art
• Art analysis
• Pigments and colours
• Ancient art: today's technology
• Psychology and art theory
• Art and archaeology
• Artists as chemists
• The physics of restoration and conservation
• Ancient Egyptian art
• Ancient Greek art
• Ancient Roman art
• Classic chemistry demonstrations
• In search of solutions
• In search of more solutions
• Creative problem-solving in chemistry
• Solar spark
• Chemistry for non-specialists
• Health and safety in higher education
• Analytical chemistry introductions
• Exhibition chemistry
• Introductory maths for higher education
• Commercial skills for chemists
• Kitchen chemistry
• Journals how to guides
• Chemistry in health
• Chemistry in sport
• Chemistry in your cupboard
• Chocolate chemistry
• Adnoddau addysgu cemeg Cymraeg
• The chemistry of fireworks
• Festive chemistry
• Education in Chemistry
• Teach Chemistry
• On-demand online
• Live online
• Selected PD articles
• PD for primary teachers
• PD for secondary teachers
• What we offer
• Chartered Science Teacher (CSciTeach)
• Teacher mentoring
• UK Chemistry Olympiad
• Who can enter?
• How does it work?
• Resources and past papers
• Top of the Bench
• Schools' Analyst
• Regional support
• Education coordinators
• RSC Yusuf Hamied Inspirational Science Programme
• RSC Education News
• Supporting teacher training
• Interest groups

• More navigation items

Separating sand and salt by filtering and evaporation

In association with Nuffield Foundation

• Four out of five

Task students to separate an insoluble material from a soluble one in this experiment using sand and salt

This is a very straightforward experiment. It can be carried out individually or in groups of two. Pupils must stand up during heating activities and beware of hot salt spitting when evaporation is almost complete.

• Eye protection
• Beaker, 250 cm 3
• Glass stirring rod
• Filter funnel
• Filter paper
• Conical flask, 250 cm 3
• Evaporating basin
• Bunsen burner
• Heat resistant mat
• Mixture of sand and sodium chloride (salt), about 6–7 g per group of students (a suitable sand–salt mixture should contain approximately 20% salt by mass)

Health, safety and technical notes

• Wear eye protection throughout this experiment.
• Pupils must stand up during heating activities and beware of hot salt spitting when evaporation is almost complete.
• Sodium chloride (eg table salt), NaCl(s) - see CLEAPSS Hazcard HC047b .
• Pour the sand–salt mixture into the beaker so that it just covers the base.
• Add about 50 cm 3  of water, or add water until the beaker is about one-fifth full.
• Stir the mixture gently for a few minutes.
• Filter the mixture into a conical flask.
• Pour the filtrate into an evaporating basin.
• Heat the salt solution gently until it starts to decrepitate (spit). CARE: Keep eye protection on and do not get too close.
• Turn off the Bunsen burner and let the damp salt dry in the dish.

Source: Royal Society of Chemistry

Equipment for a class experiment to separate a mixture of sand and salt.

Teaching notes

If desired, the experiment can be extended to isolate dry samples of sand and salt. To do this, the damp sand in the filter paper can be transferred to another sheet of dry filter paper, and, by folding and dabbing, the sample can be dried. If necessary, another piece of filter paper can be used.

Students often like to present their specimens in small bottles for approval, so a spatula could be used to accomplish this. While the first student of a pair is transferring the sand, the other can be scraping the dried salt from the evaporating dish and transferring it to another specimen bottle.

If this extension is carried out, the students should be encouraged to label the bottles. They should be told that all samples prepared in this way need to be labelled, even if in this case, it should be obvious which substance is which.

Student questions

• Why can sand and salt be separated using this experiment?
• Why is the salt, sand and water mixture stirred in step 3?
• Why is the salt solution heated in step 6?
• How might the final traces of water be removed from your samples to ensure that they are totally dry?
• Give two reasons why the sand you have obtained might still be contaminated with salt.
• How could you adapt your experiment to obtain a purer sample of sand?
• Give two reasons why the salt you have obtained might still be contaminated with sand.
• How could you adapt your experiment to obtain a purer sample of salt?

Primary science teaching notes

If you teach primary science, the following information is designed to help you use this resource.

Skill development

Children will develop their working scientifically skills by:

• Drawing conclusions and raising further questions that could be investigated, based on their data and observations.
• Using appropriate scientific language and ideas to explain, evaluate and communicate their methods and findings.

Learning outcomes

Children will:

• Observe that some materials will dissolve in liquid to form a solution.
• Describe how to recover a substance from a solution.
• Use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering, sieving and evaporating.
• Demonstrate that dissolving, mixing and changes of state are reversible changes.

Concepts supported

Children will learn:

• That there are various techniques that can be used to separate different mixtures.
• That dissolving is a reversible reaction.
• That not all solids are soluble.
• That the rate of dissolving can be affected by various factors.
• That melting and dissolving are not the same process.

Suggested activity use

This activity can be used as a whole-class investigation, with children working in small groups or pairs to look at how to separate the salt and sand. This could provide a stimulus for further investigations looking at how to separate other mixtures of solids, either of different particle sizes or by solubility. 

Practical considerations

Primary schools often don’t have Bunsen burners, so viable alternatives need to be sourced. Similarly, it may be difficult to source the equipment needed to evaporate water to recover the dissolved salt. Head stands and tea lights can work well as possible alternatives.

When carrying out this activity be aware that some insoluble solids are able to form suspensions. This is where the particles appear to have dissolved, when in fact they have been spread out throughout the liquid. A good indicator that a suspension has formed is that the liquid will go cloudy or the particles can be heard scraping as the mixture is stirred.

The layout of this activity is very prescriptive as the procedure is set out on a step by step basis. An open challenge activity, with children working in small groups and devising their own methods, would extend the children’s thinking. Different groups’ suggestions could be compared and evaluated as a class.

Additional information

This is a resource from the  Practical Chemistry project , developed by the Nuffield Foundation and the Royal Society of Chemistry.

Practical Chemistry activities accompany  Practical Physics  and  Practical Biology .

© Nuffield Foundation and the Royal Society of Chemistry

• 11-14 years
• 14-16 years
• Practical experiments
• Compounds and mixtures

Specification

• AT.4 Safe use of a range of equipment to purify and/or separate chemical mixtures including evaporation, filtration, crystallisation, chromatography and distillation.
• Mixtures can be separated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography. These physical processes do not involve chemical reactions and no new substances are made.
• AT4 Safe use of a range of equipment to purify and/or separate chemical mixtures including evaporation, filtration, crystallisation, chromatography and distillation.
• 4 Safe use of a range of equipment to purify and/or separate chemical mixtures including evaporation, filtration, crystallisation, chromatography and distillation
• Safe use of a range of equipment to purify and/or separate chemical mixtures including evaporation, filtration, crystallisation, chromatography and distillation
• (i) atoms/molecules in mixtures not being chemically joined and mixtures being easily separated by physical processes such as filtration, evaporation, chromatography and distillation
• 1.9.5 investigate practically how mixtures can be separated using filtration, crystallisation, paper chromatography, simple distillation or fractional distillation (including using fractional distillation in the laboratory to separate miscible liquids…
• 2. Develop and use models to describe the nature of matter; demonstrate how they provide a simple way to to account for the conservation of mass, changes of state, physical change, chemical change, mixtures, and their separation.

Related articles

Solubility | Review my learning worksheets | 14–16 years

By Lyn Nicholls

Identify learning gaps and misconceptions with this set of worksheets offering three levels of support

Representing elements and compounds | Review my learning worksheets | 14–16 years

How to teach chromatography at post-16

2024-03-11T04:00:00Z By Andy Markwick

Everything you need to help your students master the fundamentals of this analytical technique

2 readers' comments

Only registered users can comment on this article., more experiments.

‘Gold’ coins on a microscale | 14–16 years

By Dorothy Warren and Sandrine Bouchelkia

Practical experiment where learners produce ‘gold’ coins by electroplating a copper coin with zinc, includes follow-up worksheet

Practical potions microscale | 11–14 years

By Kirsty Patterson

Observe chemical changes in this microscale experiment with a spooky twist.

Antibacterial properties of the halogens | 14–18 years

By Kristy Turner

Use this practical to investigate how solutions of the halogens inhibit the growth of bacteria and which is most effective

• Contributors
• Email alerts

Site powered by Webvision Cloud

June 7, 2012

Salty Science: How to Separate Soluble Solutions

A fun chemistry challenge from Science Buddies

By Science Buddies

Key concepts Chemistry Solubility Water Temperature Introduction Have you ever mixed sand and salt together and wondered how you could separate them again? If you had to separate them, would you have nightmares of tiny tweezers, a magnifying glass and hours spent picking grains of salt and sand apart? Don't be afraid, there is another way! Using the differences in solubility between salt and sand, you can find the simple "solution" to this problem. Background Chemistry for the most part is the study of matter and how it behaves and interacts with other kinds of matter. Everything around us is made of matter. One important property that matter has is solubility. We think about this when we dissolve something in water. If a chemical is soluble in water, then when you add it to water it will dissolve, or disappear. If it is not soluble, then the chemical will not dissolve and you can see it, either suspended in the water or at the bottom of the container. When a chemical is dissolved in a liquid, such as water, it creates a solution. In a solution, the liquid is the solvent, and the soluble chemical that is added to and dissolves in the liquid is the solute. Even though a solvent dissolves a solute, the latter blends in but is still there. If you evaporated all of the liquid from the solution, you would be left with the dry solute again. In fact, this is how salt is processed in giant salt flats where seawater is slowly evaporated, leaving behind huge amounts of sea salt. Materials •    Strainer (optional) •    Salt •    Sand •    A napkin •    Magnifying glass •    Two glass jars with lids •    Measuring cup •    Water •    Teakettle or pot •    Two spoons •    Stove and oven •    Funnel •    Coffee filter •    Spoon •    Oven mitts Preparation •    If the sand has a lot of debris in it, use a strainer to strain out the large debris and purify the sand. •    Place some salt and sand separately on a napkin and, using the magnifying glass, closely examine the salt and sand. What do you notice? How does the size, shape and color of the grains of sand compare with the grains of salt? •    Be careful when using the stove and oven, and when handling the boiling water. An adult should help you with these steps. Procedure •    In a glass jar add one quarter cup of salt and one quarter cup of sand. Put the lid on the jar and shake until the salt and sand are completely mixed together.* •    Using the magnifying lens, closely examine the mixture. What do you notice? Can you still see the individual grains of salt and sand? •    Fill the teakettle or pot with at least one cup of water. Heat the water on the stove until it is boiling. Be careful when using the stove and handling the boiling water. An adult should help you with this. •    Very carefully pour one half cup of boiling water into the jar and stir the mixture with a spoon. Be careful when handling the boiling water, which will make the jar become very hot! (Caution: You should pour the water very slowly, so the glass jar does not shatter from a rapid change in temperature.) •    Using the magnifying lens, closely examine the solution. What do you notice? Can you still see the individual grains of salt and sand? •    Place the coffee filter in the funnel and place the funnel on top of the second glass jar. Slowly pour the entire solution over the filter. As the solution seeps through the filter, let it collect in the second jar. •    Looking at the coffee filter, what do you see? Carefully scrape off any particles from the coffee filter with a spoon and place them in the first jar. •    Turn the oven on to 325 degrees Fahrenheit. Be careful when using the oven and ask an adult to help you with this. Place both jars on to a cookie sheet and bake them in the oven until all of the water has evaporated from them. This may take over an hour. When you check on the jars to see how much water has evaporated, what do you notice? •    Turn off the oven and let it cool down. (When glass changes temperature very quickly, it can shatter.) Then, using oven mitts, carefully remove the jars and allow them to cool to room temperature. They will probably still be very hot! •    After the jars are cool, closely examine their contents using the magnifying glass. What do you notice? Can you still see the individual grains of salt and sand? Are they mixed together or separated? •    Extra : At the end of this activity, you can carefully use a measuring cup to measure the amount of salt and sand you ended up with. Do these amounts match the amounts you started with? Why do you think this happened? •    Extra : Many different chemicals have different degrees of solubility. By adding different amounts of salt, sugar or baking soda to water you can see how soluble each chemical is. Just add each chemical, one teaspoon at a time, to a half-full glass of water until you notice that it no longer dissolves when you stir it. Which chemical is the most soluble (dissolves the most into the same amount of water); which chemical is the least soluble? •    Extra : How might temperature affect the solubility of a chemical? Try dissolving the same amount of sugar in hot water, room-temperature water and ice-cold water, using the same amount of water each time. What happens? Can you think of other variables that might affect solubility?

* Correction (6/11/12): The sentence was edited after posting to remove reference to liquids; at this stage in the activity, only solids —sand and salt— have been mixed.

Observations and results When you added the boiling water, did the salt dissolve or disappear? After drying in the oven, did the salt appear in the second jar and mostly the sand was in the first jar? Salt is soluble in water whereas sand is insoluble (not dissolvable ) in water. If sand were soluble in water, we would not have beautiful sandy beaches! Because of this, when the boiling water was added to the mixture of salt and sand, the salt should have dissolved, or disappeared, whereas the sand stayed visible, creating a dark brown solution with possibly some sand particles stuck on the walls of the jar. Temperature can affect the solubility of a chemical, and in the case of salt in water the hot temperature of the boiling water improved the salt's ability to dissolve in it. The dissolved salt should have easily made its way through the coffee filter and into the second jar whereas the muddy, undissolved sand particles became stuck on the coffee filter (possibly mixed with some salt as well). After the liquid in the two jars was evaporated in the oven, the salt in the second jar should have become apparent again, mostly as a crusty white substance along the sides and the bottom of the second jar. More to explore Matter from Chem4Kids.com Solutions from Chem4Kids.com A Soluble Separation Solution from Science Buddies

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing . By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

This activity brought to you in partnership with Science Buddies