8 Short Scientific Method Examples

Problem: Ice cubes and their melting time.

Observation: Place each ice cube on a plate of different material, on them observe the time it will take for them to melt. Why don’t the ice cubes melt at the same time?

Hypothesis: Possibly one of the plates is a heat conductor, and therefore makes the ice melt faster.

Experimentation: Verify after a certain period of time which of the cubes are melting faster and in which type of container.

Conclusion: According to this, it can be said that when a solid is heated, its temperature increases until it begins to melt and passes to liquid form. At this point the temperature remains constant until the solid melts completely (melting point).

This occurs mainly due to the material in which the ice is exposed because wood and metal do not have the same properties, especially because metals are excellent conductors of heat, as they transfer heat through a substance, which is carried by two components with different temperatures, the same appear from the hottest component (metal) to the coldest (ice), until both have the same temperature, something that does not happen with wood because it does not have this feature.

Problem: Why do certain substances change state with liquid?

Observation: Observes minority substances (ice) in a solution, i.e. these substances are dissolved in a specific solvent (water).

Hypothesis: How does ice change in different presentations?

Experimentation: Initially, place several ice cubes in a glass, then add water filling it up to the rim to float the ice cubes. You will notice that the ice was not completely submerged in the water because the water pushes it, since ice has a lower density (1 g/cm3). After a certain time, the ice increases in volume and decreases in diversity, that is why it overlaps the water and at the moment of melting it does not become completely water, since the ice that was protruding turns into vapor (although it is not visible to the naked eye) and the part that is inside the water returns to its liquid state. Here, we speak of “solubility”, since it is the amount of solute that can dissolve in water.

Conclusion: Solubility is when a soluble solid is combined with a liquid, the solid begins to dilute and the concentration of the solute gradually increases. Once the entire solid has been diluted, the concentration remains constant and is defined by the weight of dilute solute and the volume of the separation.

According to this reasoning, to understand the definition of solubility it is necessary to know the terms solute and solvent. The solute is the substance that dissolves in another substance, while the solvent is the substance that dissolves the solute. The solubility of a matter depends on the condition of the solute and the solvent, as well as the temperature. As an example, we can say that we use different solvents on a daily basis, such as water, for paints used in the interior of the house; tinner, for enamel or oil paints; alcohol, for the ink of some markings, among others.

Problem: At what temperature does the liquid evaporate the fastest?

Observation: You must be very careful to calculate the time and temperature at which the liquid placed in the device evaporates.

Hypothesis: When an artifact is in a heat source for a short time, the liquid evaporates quickly.

Experimentation: You will observe that at first the pan was at room temperature, then when you placed it in the heat source for a few seconds, the temperature increased, you added drops of water where you could see that they evaporated faster, since the drops remained united; on the contrary, when the pan was in the heat source for a longer time, the drops separated, evaporating slower. Here, the process called “boiling point” takes place.

Conclusion: Accordingly, we can say that when a liquid is heated, its temperature increases until bubbling is evident. In this way, the temperature remains constant, i.e., the liquid is bubbling, boiling or boiling and passes into the gas form, i.e., evaporates.

Problem: What happens when hot air and moisture in a piece of cloth are placed together in a bag?

Observation: Place the bag near the hot air along with a piece of cloth and observe what happens minutes later.

Hypothesis: The formation of water droplets from evaporated water in a plastic bag with hot air.

Experimentation: Put the bag with a little air over the heat source, then place a damp cloth around it, in a few minutes some small drops of water begin to form in some parts of the bag; this is because the evaporated water condenses to form several drops. Subsequently, when the bag cools down, these droplets fall in a liquid state, as, for example, rain. Here, the process called “condensation” takes place.

Conclusion: According to this, we can conclude that condensation is the change of state obtained in a matter when it passes from the gaseous state to the liquid state. Both temperature and pressure can vary depending on the substance to be condensed.

Problem: Which substances have different densities and which substances do not?

Observation: Observe the different substances presented for the experiment, their attraction and rejection.

Hypothesis: The density of different substances together with the incorporation of objects, to verify the gravity that exists between them.

Experimentation: In a bottle go incorporating various substances such as water, honey, oil, alcohol; it is observed that each of them has different densities. Honey is denser, then water, alcohol and oil. The molecules of a liquid are related as in the case of water and alcohol, they will attract each other; on the contrary, if the molecules do not join, as in the case of water and oil, there is no attraction, and the less dense liquid will remain on top of the denser one.

Subsequently, he closes the bottle to mix all the substances, after a few minutes it is observed that all the substances return to their initial place, being the honey the first to settle because it has greater density. Finally, incorporate a nail, a grain of rice and a staple; all of them fall at the same time due to the gravity acting on them. Here, we speak of “density”, since this property depends on the mass and volume corresponding to a given amount of matter.

Conclusion: Density thus depends on the mass/volume ratio and is defined as the mass included in a unit volume. The greater the amount of matter included in a unit volume, the greater the density of the substance and vice versa. The mass/volume ratio is a constant value for each substance. In this regard, the density of water is 1 g/cm3, of oil 0.92 g/cm3, of alcohol 0.789 g/cm3 and of honey 1.402 g/cm3.

On the other hand, we can explain the gravitational fact of the experience based on the law of gravity or the law of falling bodies discovered by Galileo Galilei and perfected by Isaac Newton, which refers to the fact that the bodies, in this case the nail, the staple and the grain of rice, fall into the vacuum of the bottle with the same speed because they have equal or similar weights.

Problem: Does pressure play a major factor when inflating a balloon?

Observation: You must be aware of when the pressure plays a fundamental role so that the balloon can be inflated.

Hypothesis: The difference in pressure at different temperatures causes the balloon to inflate or not, inside or outside the bottle.

Experimentation: At first, arrange hot water in a glass bottle for a few seconds, then remove the liquid and place a balloon in the mouth of the bottle. Check that the bottle after having removed the water, is still hot; equalizing its temperature with the ambient temperature, because it will use the atmospheric pressure to equalize also the pressure inside the bottle. The ambient pressure will intervene in the equilibrium of the process. Also note that the balloon is sucked into the bottle (trying to inflate), trying to expand so that the pressure can be adjusted.

Finally, perform the same procedure, but after having removed the hot water from the bottle and having placed the balloon in it, put it inside a container with ice; when the system cools down, it will return to its initial temperature, to its initial state. The balloon that tried to inflate inward from the beginning, after some time in cold temperature, makes the attempt to come out. Here, we speak of “pressure”.

Conclusion: We conclude that air pressure and atmospheric pressure have a close relationship, since the force exerted on the bottle will depend on them, in addition to the temperature at which it is exposed. Generally we think that pressure is the amount of force exerted on an object in question; when an element is immersed in it, it is also under a temperature rise that increases its volume causing what was observed in the experience.

Problem: Why do some objects move?

Observation: Verify if the material to be used allows the mobility of the coin and other objects such as the pencil sharpener, eraser, spinning top, or that all of them are in a resting state.

Hypothesis: The movement of the coin and other objects on different surfaces.

Experimentation: Two procedures:

In procedure (a), observe that regardless of the material that you place over the mouth of the glass (1 playing card, 1 white sheet, 1 piece of cardboard), when you give it a strong blow, it makes the coin that is on it move, from being in a state of rest to being in a state of movement. When using 1 piece of cloth, it took a little longer for the coin to fall through the surface of the cloth, since it is not firm, therefore, the shape of the material influenced this procedure.

Conclusion procedure (a): Here, the “Law of Inertia” is developed. The blows given to the different materials made the coin move, and its inertia kept it in its position, but as gravity was acting on it, it made it fall to the bottom of the glass.

In procedure (b), observe that the objects (pencil sharpeners, erasers, coins, spinning top) that are on top of the sheet, at the end that is exposed on the table, are in a state of rest. Then, at the moment of pulling the other part of the leaf that protrudes from the table, a force is exerted, and these objects move slightly, to return to their original state (state of rest). Here, the “Law of Inertia” is developed again.

Conclusion procedure (b): According to this, inertia is the characteristic of bodies to remain still at rest – rest, or in rectilinear motion with a constant speed (unless there is some impulse that transforms this state). For this reason, the greater the inertia, the more difficult it is to modify the state of the body.

“First law. Every organism at rest continues at rest unless an external force is exerted upon it. An organism in motion continues to move with constant rapidity unless an external force is exerted on it”.

Problem: What is the force exerted on the objects?

Observation: Note that, at the moment of exerting an upward force to the table, an angle of inclination is achieved and thus the movement of the different objects can be obtained. In addition, the friction from one surface to another and the surface of the material is taken into account.

Hypothesis: The force exerted on an object helps its acceleration on any surface.

Experimentation: This procedure is performed on the wooden board with different angles and different objects:

Conclusion: It is important to note that as we increased the angle to the board (force exerted), the object fell more easily; as the angle decreased, the objects could not move. It was also performed on acrylic, where the objects slid faster, because they had less friction.

The degree of inclination of an angle will determine the force. Therefore, the greater the angle, the greater the weight. According to the base where the object is located, the friction of the object will depend on it. If an object slides faster, it means that the surface is smoother and therefore has less friction. According to this, the “Fundamental Law of Dynamics” is developed, in which when a force is exerted on a particular object, it will cause it to accelerate with the same force in which the movement was exerted, and in turn it will take the same direction in which it was executed.