Frozen Balloon - Results

Answers

Answer to question 1. All answers are correct, if you have written down what you thought that would happen.
Answer to question 2. There are small white crystals on the balloon. The water inside the balloon has become hard, it is ice. The ice is less transparent than liquid water. Often you can see cracks in the block of ice.
Answer to question 3. All answers are correct, if you have written down why you thought this happened. The ice crystals appear on the balloon, because water from the air freezes on the balloon surface. The water in the balloon freezes at a temperature below 0 degrees Celsius. Because the temperature is below zero in a freezer, the water freezes and becomes ice. Cracks can appear because not all parts of the water freeze at the exact same moment.
Answer to question 4. The ice is floating in the water. A small part of the block of ice is above the water surface.
Answer to question 5. All answers are correct, if you have written down why you thought is happening. When water freezes, it increases in size. The water becomes larger, while it remains as heavy as before. Therefore one liter of ice is less heavy than one liter of water. And because the ice is less heavy, is will float.

Extra Explanation

When you keep water in a freezer for a longer period of time, it cools down and freezes. We call frozen water ice. The particles of the water, the water molecules, are stacked on top of each other, and this is why ice is solid and hard.

When water freezes, no new water molecules appear. So the mass of the water remains the same. But the water does increase in size, so the volume becomes larger. When its mass remains the same and the volume becomes larger, the density (mass per volume) becomes smaller. You can also say that a liter of frozen water weighs less than a liter of liquid water.

The ice will float in water, because a liter of ice weighs less than a liter of liquid water. A part of the ice is above the water surface. This part has approximately the same size as the size of the water has increased. Only the 'tip of the ice berg' is above the water surface, when ice floats in water, the rest of the ice is below the surface.

Once you remove the ice from the water, after a while, you can clearly see the part that was above the surface and the part that was below it. The ice melts faster in the water than in air. You can clearly see the edge up to where the ice has melted faster.