[Physics Class Notes] on Impact of Temperature Pdf for Exam

The hotness and coldness of an object is its temperature. The units of temperature are ℃, ℉, and K. The units of temperature were named after the name of the following scientists:

℃ = Anders Celsius

℉ = Daniel Gabriel Fahrenheit

 Thermodynamic Temperature – K = William Thomson, 1st Baron Kelvin 

High temperature affects the oceans, weather, snow/ice, plants, and animals. The warmer the environment becomes, the harder the survival of living beings becomes. A rising temperature and its effects can be seen in a sudden change in weather, on PV cell characteristics, on the rate of reactions in Chemistry, and so on.

Impact of Temperature 

In this article, we learn the rise of temperature and its effects on the following places:

Impact of Temperature on Viscosity 

We know that fluids comprise two things viz: liquid and gas. The molecules in the liquid are close to each other, while in gases, these molecules are far away.

Impact of Temperature on Viscosity of Liquids

When you heat a liquid, the intermolecular distance increases. As we know, liquids have a good amount of cohesive force between the molecules that resist its easy flow over the surface. On raising the temperature, the strength of cohesive forces decreases, which, in turn, decreases the resistance to flow in the liquid. 

We also know that the resistance to the liquid flow is viscosity. When the temperature rises, the liquid viscosity decreases.                 

A practical example can be seen in vehicles. 

During winters you find it difficult to start your two-wheeler with the self-start. 

What you do is, apply three-to-four kicks with the choke pulled up. Do you know why we do this? Let’s understand it:

After applying kicks, your engine sets. As soon as your scooter starts, you keep it started in a standing position till the oil in the vehicle melts because in the winter season, the oil becomes thick or solidifies, i.e., attains higher viscosity, so when the temperature in the vehicle rises by the power offered through the kick, the oil becomes thin (viscosity of the oil decreases) and you’re all set to drive your two-wheeler now.

You can find the graph for the above scenario below:

(Image to be added soon)

Now, talking about the impact of temperature on gases

Impact of Temperature on the Viscosity of Gases

In the case of gases, when the temperature rises, the gas molecules collide with each other because of which the resistance increases. It means that the viscosity of gases increases with the temperature rise. So the graph for this case will be:

(Image to be added soon)

Impact of Temperature on Internal Resistance

On increasing the temperature of the conductor, the kinetic energy of electrons increases, which means the relaxation time decreases. When the relaxation time decreases, then by the following relationship:

                   R = [frac{ml}{ne^{2}Atau }]

Where,

N = electron density

τ = relaxation time

l = length of the wire

m = mass of an electron

A = cross-sectional area

e = charge

The change in the resistance of conductors depends upon the following factors:

From the above equation, we can see that R ∝ 1/τ . So, when the temperature increases, the resistance of the conductor also increases.

Impact of Temperature on the Rate of Reaction

Let us study the reaction of oxalic acid with potassium permanganate in the presence of sulphuric acid:

Take 0.5 g of oxalic acid (C2H2O4) crystals and dissolve them in 20 ml of water in a beaker to make a solution. Now, pour 5 ml of dilute H2SO4 into the solution and add a few drops of KMnO4 solution into the mixture.

What Do You Observe? 

The solution turns pink. Now, stir the solution with a glass rod. After some time, the solution remains pink. 

Now, prepare the solution of oxalic acid as we did earlier with the same quantities. Now, heat the solution to 60-80 ℃ and add a few drops of KMnO4 solution to it. You observe that while stirring the solution it becomes colourless. 

Our desired result was to obtain a colourless solution. Now, as the solution becomes hot, the rate of reaction of the reaction of C2H2O4  with KMnO4 increases, and the colour disappears. 

Impact of Temperature on Weather and Climate

The rise in temperature leads to global warming. It can cause the following environmental issues:

• It can reduce the water levels in oceans, 

• Sudden changes in climatic conditions

• Melting of ice in glaciers

• Depletion of the ozone layer and the direct reach of UV-rays to the Earth’s surface.

The rise in temperature leads to the spread of heat waves; these heatwaves lead to illnesses like heat cramps, heat strokes, and even death.

We face many health issues like skin diseases, dryness, ecological imbalance, global warming, and so on.