1. Introduction

1.1 Background information

Global warming is the long-term heating of Earth’s climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere (NASA, 2022). It is the cause of sea ice in the north pole to start melting. Global warming has become such a big global threat that it has caught NASA’s attention, in which they are now looking into global warming. Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about 1 degree Celsius, a number that is currently increasing by 0.2 degrees Celsius per decade (NASA, 2022). Because of this, sea ice has been decreasing in extent and thickness (Maggy Hunter Benson, 2022). On the other hand, the water level on seas is rising quickly. By 2040, Arctic sea ice may disappear altogether during the summer months (Maggy Hunter Benson, 2022).

1.2 Specific topic and its importance

In this experiment, we are trying to determine if salt concentration can affect the freezing point of water. This could allow us to discover a new way to prevent the Arctic sea ice from melting, thus preserving the habitats of many animal species.

1.3 Previous research

The bright surface of sea ice reflects a lot of sunlight out into the atmosphere and, importantly, back into space. Because this solar energy " bounces back" and is not absorbed into the ocean, temperatures nearer the poles remain cool relative to the equator (NOAA, 2021). This will also help to reduce the rate of rising sea levels. Glaciologists believe that, despite the massive ice loss, we do still have time to save the glaciers from their predicted disappearance. This will also help reduce the effects of these 4 problems, Sea level rise: Glacial melting contributed to rising sea levels by 2.7 centimeters since 1961. Furthermore, the world's glaciers contain enough ice — about 170,000 cubic kilometers — to raise sea levels by nearly half a meter, Impact on the climate: Glacial thawing at the poles is slowing the oceanic currents, a phenomenon related to altering the global climate and a succession of increasingly extreme weather events throughout the globe, Disappearance of species: Glacial melting will also cause the extinction of numerous species, as glaciers are the natural habitat of a number of animals, both terrestrial and aquatic and Less freshwater: The disappearance of glaciers also means less water for consumption by the population, a lower hydroelectric energy generation capacity, and less water available for irrigation (IBERDOLA, 2022). SALINITIES OF H20-SALT inclusions are most often determined by measuring the melting temperature of the ice in the inclusion and then referring this value to an equation or table describing the relationship between salinity and freezing-point depression. In the low-salinity range (less than about 10 wt%) the difference between the results of HALL et al. (1988) and previously published data for H20-NaCl is small, and the equations of POTTER et al. (1978) and HALL et al. (1988) agree within +O. 1 “C or +O. 1 wt%. However, the equations of POTTER et al. (1978) and HALL et al. (1988) begin to diverge at higher salinities, and the magnitude of the difference increases with increasing salinity. Based on their new experimental data, HALL et al. (1988) presented an equation relating to freezing temperature and salinity. Salinity = 0.00 + 1.78 -+, (1) where is the depression of the freezing point in degrees Celsius. Table 1 may be used to obtain the salinity corresponding to a measured freezing temperature for any temperature between 0.0 and the eutectic temperature of -21.2” C (Bodnar, R.J., 1993). In a nutshell, salt is a great ice melter because it causes “freezing point depression.” This means that salt helps in lowering the freezing point and, consequently, the melting point of water (the main component of snow and ice). In its pure state, water freezes at 0°C or 32°F. By using salt, that freezing point can be lowered which forces the ice to melt and prevents the water from freezing or re-freezing. With 10% salt solution, water freezes at 20°F (-6°C) With 20% salt solution, water freezes at 2°F (-16°C) It must first be combined with water to start the melting process. Fortunately, ice and snow are generally covered with a thin film of water. As salt touches this water, it starts to dissolve – subsequently lowering the freezing point and melting the ice surrounding it (Kissner, 2019).

1.4 Conclude the Introduction

1.4.1 Specific objectives of the research

Hence these studies indicate that the salinity of water affects the freezing point of water. If this hypothesis holds, we would have a convenient way of knowing how fast the polar ice caps would melt as global temperatures increase, and we could use this to reduce the rate of the polar ice caps melting by getting rid of or increasing salt levels. However, to verify our hypothesis, we would need to experiment to show the relationship between salinity and the melting point of water.

1.4.2 Research Questions

Our Research Question is:

How do different salt concentrations affect the freezing point of water?

1.4.3 Research Hypotheses

Our hypothesis is that the freezing point of water will decrease as the salt concentration increases.

1.4.3.1 Independent variable

The independent variable is the salt concentration in the water. Specifically, it is the mass of salt in g against 1kg of water.

1.4.3.2 Dependent variable

The dependent variable is the freezing point of water.

1.4.3.3 Controlled variables

a) The location of the sampling should be the same

b) the amount of water in each sample should be the same.

c) The sampling period should be around the same time.

d) Type of container should be the same