Question

EXPERIMENT: FORMS OF CHANGE

Here are your goals for this lesson:

Determine the change as physical or chemical
Write a scientific report including the specifications given in the experiment

A physical change is a change in the size and shape of a substance. Hardness, shape, mass, and density are physical properties which may be involved in a physical change. In a chemical change, however, new substances with different physical properties are produced.



In this investigation, you will be conducting a simple experiment. You will classify the result as a physical or chemical change. It is up to you to determine the type of change. Use the steps of the scientific method as you work.



EXPERIMENT

Supplies needed: sugar, beaker or dish, water, stirring rod or teaspoon

Instructions:

1. Place several teaspoons of sugar in a small beaker half full of water, and stir until the water is clear.

2. Pour some of the solution into a dish. Set the dish on a shelf or a windowsill. Observe the dish for a day or two. Record what you observe.



Compile a scientific report from your hypotheses, observations, data, inferences, and conclusions. Be sure to answer the questions below in your summary and include your personal findings.

What did you observe after the solution set in the dish for a day or two?

What kind of change (physical or chemical) occurred in this experiment?

How do you know the kind of change?

What happened to the sugar?

Name another mixture that could be separated in this way.

What did you find out from this experiment? Be thoughtful in your answer.

Answer 1

The experiment involves mixing sugar and water and observing the physical changes that occur as the water evaporates. The sugar dissolves in water to form a solution, and when the water evaporates, the sugar recrystallizes. This is a physical change because the identity of the sugar remains the same.

The experiment involves mixing sugar and water and observing the changes that occur over time. After the solution sets in the dish for a day or two, you may observe that the water has evaporated, leaving behind sugar crystals. This is a physical change because the size and shape of the sugar crystals have changed, but the identity of the substance remains the same.

The kind of change that occurred in this experiment is a physical change. This is because the properties of the substance (sugar) have changed, but the substance itself has not been transformed into a different substance. The sugar is still sugar, just in a different physical form.

The sugar dissolved in water and formed a solution. When the water evaporated, the sugar molecules came together and recrystallized, forming sugar crystals.

Another mixture that can be separated in a similar way is a salt-water solution. When the water evaporates, the salt will remain behind as crystals.

From this experiment, it can be concluded that when a substance dissolves in a liquid and the liquid evaporates, the dissolved substance can come together and recrystallize. This is a physical change, as the identity of the substance remains the same.