1f) Write down any four properties of objects that cannot be known by observation but can be found out through experiments.

 Here are four properties of objects that cannot be known by observation alone but can be determined through experiments:

1. Density

   • Requires measuring the object's mass and volume, then calculating density using the formula $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.

2. Melting Point

   • Found by gradually heating the object and observing the exact temperature at which it transitions from solid to liquid.

3. Electrical Conductivity

   • Determined by connecting the object in an electrical circuit and measuring its ability to conduct electricity.

4. Reactivity with Other Substances

• Observed by testing how the object reacts with acids, bases, or other chemicals (e.g., does it produce bubbles, heat, or new substances?).

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