Separating sand and salt
In this experiment students separate a mixture of sand and salt, illustrating the fundamental means of separating a mixture of an insoluble material from one which is soluble.
Read our standard health & safety guidance
Lesson organisation
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.
Apparatus and chemicals
Eye protection
Beaker (250 cm3)
Glass stirring rod
Filter funnel
Filter paper
Conical flask (250 cm3)
Evaporating basin
Bunsen burner
Heat resistant mat
Tripod
Gauze
Mixture of sand and salt (Low hazard), about 6 or 7 g per group of students (see note 1)
Technical notes
Salt (sodium chloride) (Low hazard) Refer to CLEAPSS Hazcard 47B
1 A suitable sand-salt mixture should contain approximately 20% salt by mass.
Procedure
HEALTH & SAFETY: Wear eye protection throughout this experiment.
a Pour the sand-salt mixture into the beaker so that it just covers the base.
b Add about 50 cm3 of water, or add water until the beaker is about one-fifth full.
c Stir the mixture gently for a few minutes.
d Filter the mixture into a conical flask.
e Pour the filtrate into an evaporating basin.
f Heat the salt solution gently until it starts to decrepitate (“spit”). CARE: Keep eye protection on and do not get too close.
g Turn off the Bunsen burner and let the damp salt dry in the dish.
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. Whilst 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
Here are some questions for students.
a Why can sand and salt be separated using this experiment?
b Why is the salt, sand and water mixture stirred in step c?
c Why is the salt solution heated in step f?
d How might the final traces of water be removed from your samples to ensure that they’re totally dry.
e Give two reasons why the sand you have obtained might still be contaminated with salt.
f How could you adapt your experiment to obtain a purer sample of sand?
g Give two reasons why the salt you have obtained might still be contaminated with sand.
h How could you adapt your experiment to obtain a purer sample of salt?
Health & Safety checked, April 2008
Updated 29 Oct 2008Average rating: 
3 out of 5
Your reviews
Nice!
Submitted by: jahanvi on 10 November 2008
Pretty good
Submitted by: Anne on 14 January 2009
This site is number one.
Submitted by: demoy reid on 18 March 2009
It was good, helped me for a test - thanks.
Submitted by: benny on 23 July 2009
Nothing - it's already brilliant.Keep up the good work! If only other sites were like this.
Submitted by: dinah on 28 September 2009
Great!
Submitted by: salt+sand on 1 November 2009
The experiment was a good one, the steps were clear and precise but the numbering of the materials would have made it better.
Submitted by: Ravi Balchan on 27 January 2010
Really good, helped me with my homework and for a test! :) Keep up the good work :)
Submitted by: Emma O on 10 February 2010
Really does work - it helped me to excel in my chemistry assignment.
Submitted by: wanano sheperd maposa on 11 February 2010
Your site's great. It is simple yet the experiment is great for younger students.
In chemistry we had to apply this experiment to another. After separating salt and sand, we had to gravimetrically analyse each component.
Submitted by: Bob on 21 February 2010
Why don't you put a explanation for the experiment? It may help and be a bit more interesting for people looking at your site.
Submitted by: cordelia on 26 February 2010
I want to answer number (b) Why is the salt, sand and water mixture stirred in step (c)? They stir so that the salt dissolves in the water. I am a 7th grader.
Submitted by: Maryann joe on 12 March 2010
Needs more examples, but good for homework.
Submitted by: ben dingdong on 20 April 2010
I think it was not bad. Thanks!
Submitted by: Zhou Zhefang on 27 May 2010
That was good!
Submitted by: Ike Abaah on 3 June 2010
I think that was cool but we need more.
Submitted by: majeed mohammed on 3 June 2010
Great! Very very helpful, I got an A+ on my test for Science!!!! I can't believe it either so Thank You very much for this awesome website. I also actually think that it could've used the sizes (where possible) of the materials needed. For example: Filter Funnel (400cm) just like the Beaker and that. But in other words it was very helpful so thank you. I really do appreciate it!
Submitted by: Anonymous on 19 August 2010
Good, but please tell us how to do this using simple items available at home.
Submitted by: Anirudh G on 29 August 2010
Explain more details, please.
Submitted by: Superdiva on 11 November 2008