What plants need to grow well
Biology · Key Stage 1 · The School
The water highway
Water goes in through root hairs. It travels up tiny tubes inside the stem. Then it leaves through the leaves as vapour. That escape at the top PULLS the next drop up. It is like sucking through a straw. But evaporation does the work. Put a white flower in coloured water overnight. The petals will show you the route in colour.
Leaves are food factories
Leaves are flat and wide. That helps them catch as much light as possible. They are green because of chlorophyll. Chlorophyll is the substance that captures light energy. A leaf uses light, water and a gas from the air. With those it builds sugar. Plants make their own food. Animals cannot. That is why every food chain starts with a plant.
Recording properly
Measure the same way each time. Same ruler. Same day of the week. From the soil to the tip. Put your results in a table. Put the units in the heading, like Height in cm. Then draw a line graph. A table you can still read a month later is worth more than a careful experiment whose results you cannot remember.
Put a white carnation in a glass of water. Or use a stick of celery. Add red food colouring. Come back after a few hours. You will see red streaks in the petals. In celery you see them in the stringy tubes. Cut across the stem and you can see the coloured tubes. Nothing pumped it up there. The leaves lost water to the air. That pulled the rest up behind it. Cut the leaves off and the colour stops rising.