Experiment to separate salt and sand using filtration and evaporation.

Problem Analysis:

The task involves separating a mixture of salt, sand, and water using basic laboratory techniques. The goal is to isolate the salt from the mixture by dissolving it in water, filtering out the sand (which does not dissolve), and then evaporating the water to recover the salt.

Solution Explanation:

#### Step-by-Step Procedure and Observations:

1. Mixing Salt, Sand, and Water:
- Procedure: Add 5 grams of a mixture containing salt and sand to 250 mL of water in a 250 mL beaker glass. Stir gently.
- Observation: The salt dissolves perfectly in the water, while the sand does not dissolve and remains as solid particles.
- Explanation: Salt (sodium chloride, NaCl) is soluble in water, meaning it forms a homogeneous solution when mixed with water. Sand, being an insoluble solid, remains undissolved and can be separated later.

2. Filtering the Mixture:
- Procedure: Filter the mixture into a conical flask using a funnel and filter paper.
- Observation: The sand left in the filter paper because the particle size of sand is bigger than the pores of the filter paper, preventing it from entering the beaker perfectly.
- Explanation: Filtering is used to separate solid particles (sand) from a liquid solution (saltwater). The filter paper acts as a barrier that allows only the liquid (saltwater) to pass through while retaining the larger sand particles.

3. Evaporating the Salt Solution:
- Procedure: Pour the filtrate (the saltwater solution) into an evaporating dish and heat it gently until the water starts to "vapourize."
- Observation: The water will be evaporated, and the compound left in the evaporating dish will be white in color and still a little watery.
- Explanation: Evaporation is the process of converting a liquid (water) into a gas (water vapor). As the water evaporates, the dissolved salt remains behind in the evaporating dish. At this stage, the salt may still have some moisture, but most of the water has been removed.

4. Drying the Salt:
- Procedure: Turn off the spirit burner and let the salt dry.
- Observation: If the salt dries fully, it means that the residual compound is pure salt.
- Explanation: After evaporation, the remaining salt may still contain traces of moisture. Allowing it to cool and dry ensures that any remaining water evaporates, leaving behind pure salt crystals.

Final Answer:

The procedure successfully separates the salt from the sand and water mixture. The key steps are:
1. Dissolving the salt in water while leaving the sand undissolved.
2. Filtering the mixture to remove the sand.
3. Evaporating the water to recover the salt.
4. Drying the salt to ensure it is free of moisture.

Thus, the final product is pure salt.

$$
\boxed{\text{Pure Salt}}
$$