Test - Experiments With Water MCQ - 1 - Class 5 MCQ

• Sinking or Floating of Objects: The sinking or floating of an object in water depends on its density compared to water's density.
• Egg in Water: Typically, a fresh egg has a density greater than water, so it sinks.
• Lemon in Water: A lemon usually has a density slightly greater than water, so it also sinks.
• Conclusion: In normal conditions, both the egg and the lemon will sink in water, making option A correct.

• A bottle cap is typically made of plastic, which is less dense than water.
• Density determines whether an object will float or sink; objects with lower density than water will float.
• The cap's lightweight and its material's low density allow it to float on the water surface.

Hence, Option A is Correct.

• The Dead Sea, located between Jordan and Israel, holds the title for being the saltiest water body in the world.
• The salinity of the Dead Sea is around 34.2%, which is almost 10 times saltier than the average ocean water.
• This high salt concentration is due to the fact that the Dead Sea has no outlet for water to flow out, causing the water to evaporate and leave behind minerals and salts.

Therefore, the correct answer is Option C: Dead Sea.

• A needle sinks in water because its density is greater than that of water.
• Density is the mass per unit volume of a substance. Though a needle is small, its material (usually metal) is dense.
• Water cannot support the needle's weight due to its lower density than needle, causing it to sink.

Hence, Option A is the correct answer.

• The correct answer is sinks. When a puri is put in hot oil, it initially sinks to the bottom of the oil pan.
• The correct answer is float. As the puri starts to cook, it puffs up due to the steam formed inside. This causes it to become lighter, and as a result, it floats on the surface of the oil.
• So, the correct answer is option B: Sinks, float.

• The Dead Sea is one of the saltiest bodies of water on Earth, with a salinity level around 34%.
• This high salt content significantly increases the water's density.
• A person's body is less dense than the dense, salty water of the Dead Sea.
• Due to the principle of buoyancy, objects less dense than the fluid they are in will float.
• Thus, the increased water density in the Dead Sea makes it easy for people to float without sinking.
• Hence Option C is the correct answer

• Yes, it's true that some things float on water while others sink.
• For example, when you put a plastic bottle full of water in a tub, it usually floats.
• But if you put a heavy iron nail in the water, it sinks to the bottom.
• This happens because some things are lighter and have air in them, making them float, while heavier things sink.
• So, remember, things that are light and have air in them float, and heavy things sink!

• Nonpolar Oil: Oil doesn't dissolve in water because oil molecules are nonpolar, meaning they don't have electrical charges.
• Polar Water Molecules: Water molecules are polar, which means they have slight positive and negative charges and can form bonds with each other.
• Since oil and water molecules have different properties, they don't mix well. Instead, oil gathers together and floats on top of the water because it is less dense.

• Sugar dissolves in water easily because sugar molecules are polar, meaning they have positive and negative charges.
• These charges allow sugar to interact with the polar water molecules, leading to the sugar dissolving in water.
• In contrast, oil molecules are nonpolar and cannot mix with water, which is why oil floats on the surface instead of dissolving.

• Materials like mango jelly and papad are dried in the sun primarily to remove excess moisture.
• Sun drying reduces the water content in these foods, which helps to preserve them and prevent spoilage.
• By removing moisture, the risk of bacterial growth and decay decreases, extending the shelf life of the products.
• Additionally, drying can concentrate flavors by allowing natural sugars and other compounds to become more intense, but the main purpose is to ensure the food remains safe and stable for longer periods.