Have you ever dropped a toy in the bath? Some toys bob on top of the water. Others sink straight to the bottom. Why?

When something floats, the water pushes up on it. We call this push the water's lift. If an object is light for its size, the water can hold it up, and it floats. If it is heavy for its size, it pushes down harder than the water can lift, so it sinks.

Shape matters too! A ball of clay sinks. But press that same clay into a bowl shape, and it can float, because it pushes against more water. That is how heavy metal boats float even though metal is heavy.

Scientists test ideas like this all the time. Now it is your turn: what will sink, and what will float?

Stir a spoonful of sugar into warm water and watch closely. The sugar seems to disappear! It did not really vanish — it dissolved.

When something dissolves, it breaks into pieces so tiny you cannot see them, and they spread all through the water. The water still tastes sweet, so you know the sugar is still there.

Some things dissolve in water, like sugar and salt. Other things do not, like sand and pepper — they just stay the same. Warm water makes things dissolve faster than cold water.

Mix baking soda and vinegar and something exciting happens — it bubbles and fizzes and foams!

Those bubbles are full of a gas called carbon dioxide. A gas is a little like air: you cannot see it, but it takes up space and can push things.

When two things mix and make something brand new, scientists call it a reaction. The fizzing is a sign that a reaction is happening. The gas can even blow up a balloon or make a paper volcano erupt!

A tiny seed holds a whole plant inside, waiting. To wake up and grow, a seed needs the right things.

First, it needs water to soften and sprout. Next, it needs sunlight — plants are the only living things that can make their own food from light! It also needs air and a little warmth.

When a seed has what it needs, a small root grows down and a green shoot grows up. Slowly, leaves unfold to catch the sun.