Liquids are unique because they take the shape of whatever container they are in. This happens because of how the tiny parts that make up liquids (called molecules) are arranged and how they interact with each other.

How Molecules Are Arranged

• Close But Not Fixed: The molecules in a liquid are close together, but they aren't stuck in one place. This lets them slide past each other.
• Forces Between Molecules: The forces that hold these molecules together are not as strong as in solids. However, they are still strong enough to stop the molecules from moving apart completely.

How Temperature Affects Liquids

Temperature really matters when it comes to how liquids behave. When the temperature goes up, here’s what happens:

1. Energy of Molecules: The energy of the molecules increases. For every degree Celsius that the temperature rises, the energy goes up a little bit.

2. Flow Resistance: The resistance to flow, also known as viscosity, decreases. For instance, water becomes much easier to pour when it’s heated. At 20 °C, water's viscosity is about 0.89 mPa·s, but when it heats to 100 °C, it drops to around 0.3 mPa·s.

3. Expanding Volume: When you heat most liquids, they expand. Typically, they grow in size by about 0.000214 for every degree Celsius increase in temperature. This means that hot liquids take up more space, which helps them fit into their container better.

In short, liquids can change shape based on their containers because of how their molecules are arranged. Plus, temperature has a big impact on how easily they flow and how they act.