Rockwoods International School, Udaipur
Session – 2023-24
Grade -8
Subject-Science
Practice Worksheet-1
1 (a)Write down one reason why plants need magnesium. [1]
____________________________________________________________________________
(b) A scientist investigated whether giving plants different quantities of magnesium affected their growth.
He measured growth by counting the number of new leaves produced. Write down a hypothesis he could
test in his investigation. [1]
____________________________________________________________________________
____________________________________________________________________________
(c) Here are his results.
• 0.5 mg magnesium: 3 new leaves
• 1.0 mg of magnesium: 5 new leaves
• 1.5 mg of magnesium: 6 new leaves
• 2.0 mg of magnesium: 4 new leaves
• 2.5 mg of magnesium: 1 new leaf
Draw a results table and fill in the scientist’s results. [2]
2 Complete the sentences. Choose words from the list. [2]
Asteroid astronomer climate mass photosynthesise respire stellar weather
67 million years ago, an _________________________ collided with the Earth. This filled the air with
dust. Less light could reach the ground, so plants could not _________________________. The
_________________________ of the Earth changed, as it became cooler. Many animals could not
survive because they did not have enough food. There was a _________________________ extinction.
3 (a) Here are some statements about the carbon cycle. Tick (✓) the two correct statements. [2]
Plants take carbon dioxide from the air when they respire.
( )
Decomposers obtain their carbon from dead animals and plants.( )
Combustion of fossil fuels adds carbon dioxide to the air. ( )
Carbon dioxide is returned to the air by photosynthesis.( )
( b) Explain the difference between chloroplasts and chlorophyll. [2]
_______________________________________________________________________________
_____________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Making predictions
4 Each of these sentences is a prediction of what will happen if something else happens. Complete each
sentence. There is more than one possible way of completing each one, so do not worry if your sentences
are not the same as someone else’s.
1 If a plant does not have enough sunlight, it will
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
2 If a plant respires faster than it photosynthesises,
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
3 If a plant is growing in soil that does not have enough magnesium,
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
4 If we burn fossil fuels,
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
4 Complete the given Carbon Cycle.