• Why do we wake up from sleep?

Sleep is essential to give the brain and nerves some rest. While we sleep, our bodies too, get a chance to recover from the fatigue caused by daily activities. When we are well rested, both physically and mentally, we wake up. Sometimes, we wake up because we feel cold or hungry or because a bad dream has made us afraid.

To sum up, we all have an internal body clock that tells our brain to wake our bodies up after a certain amount of time. However, some things or situations such as noise, temperature in the room or sunshine interrupt our sleep and wake us up too.

• Why doesn’t glue stick to the insides of the bottle?

The regular white glue that we use is made up of a variety of chemicals that are either sticky or stretchy. White glue also contains water. Water acts as a solvent that keeps the glue liquid until you want it to stick. When you put glue on a piece of paper, the water in it is exposed to air. The water eventually evaporates and as it does so, the glue dries and hardens and holds the things that need to be glued, stuck together.

When the glue is inside the bottle, there’s not enough air inside the bottle to cause the water to evaporate to make the glue sticky. The bottle protects the glue from the air and keeps the glue runny. This is also why if you’ve ever left the top off a glue bottle for a while, the next time you try to use the glue, it would have dried up.

• Why do the lights of a distant town appear to twinkle?

When you are traveling at night, the lights of towns in the distance appear to twinkle. This is because of the constant movement of air above towns. The air above towns is warm, as a result of the heat given off from buildings. Warm air keeps moving up to be replaced by cold air which then gets heated and rises. This constant movement of air is known as turbulence.

When we are near a town or in it, we don’t notice the turbulence because it is quite small and the lights are nearly. However, when we are some distance away, the lights are far away too. They appear as only pinpricks. The warm and cold air that make up the turbulence above the town have different densities and light passing through the layers is bent at different angles because of this difference. As a result it appears as though the lights of the distant town are twinkling.

• Why do clouds have different shapes?

Clouds are made up of tiny droplets of water vapour or ice particles or both. The shape of the cloud depends on its height and temperature. Cumuliform clouds are shaped liked mushrooms and are formed when rising warm air cools as it goes up. Stratiform clouds come in flat, dull layers and are formed when air sinks in a high pressure area, creating a layer of cold air near the ground that doesn’t rise or rises only very slowly. Cirriform clouds are clouds that have risen on a front or tropical cyclone and frozen into ice crystals at very high altitude. They look like thin hair. The shape of cloud also depends on the time of the day.

Towards evening, clouds tend to be thinner and flatter than during daytime. Changes in wind patterns also change the shapes of cloud.

Thank you for reading. Have a nice day!🌼