Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Photosynthesis is the process by which green plants use sunlight to synthesize nutrients from carbon dioxide and water. For Grade 3, we understand this as the plant's way of 'making food' using light.
Investigation of Light: If a plant is placed in a dark cupboard, it will stop growing healthily. If a plant is placed in a box with a single hole, the stem will bend and grow towards that hole to reach the light.
📐Formulae
💡Examples
Problem 1:
Sara has two identical potted plants. She places Plant A on a sunny windowsill and Plant B inside a dark closet. She waters both plants equally. What will Sara observe after two weeks?
Solution:
Plant A will be green and healthy. Plant B will have yellowing leaves and a thin, weak stem.
Explanation:
Plant A has access to sunlight, allowing it to make food and grow. Plant B is deprived of light, so it cannot perform photosynthesis. It uses up its stored energy, loses its green color (chlorophyll), and stretches out to try and find light.
Problem 2:
Why do plants kept near a window often look like they are 'leaning' towards the glass?
Solution:
The plants are growing towards the light source.
Explanation:
This is a natural response. Since light is essential for survival, the plant moves its stem and leaves in the direction where the light is strongest to capture as much energy as possible.