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How fast does water go up a celery stem?
Prediction
1 a Water is taken up a plant’s stem to its leaves to be used in photosynthesis. Do you think water will move faster up a celery stem that has leaves or one that does not have leaves?
b Why do you think this?
Apparatus
celery stem without leaves
celery stem with leaves
beaker of food dye
stopclock
ruler
Method
A Place both celery stems in the beaker of dyed water. Put the beaker in a well-lit area.
B Time 20 minutes.
C Remove both stems at the same time and break them open lengthways. Measure how far up each stem the dye has reached.
Recording your results
2 Write your results in this table.
Considering your results/conclusion
3 You can work out how fast the dye moved using this formula:
speed = distance / time
Work out how fast the dye in each stem has moved. Show your working:
Answers:
a Speed for the stem without leaves mm/min.
b Speed for the stem with leaves mm/min.
c Which stem did water travel the fastest in?
4 Why do you think the dye moved faster in one stem than the other?
Evaluation
5 If your results (your evidence) can directly answer the question then it is valid. Is your evidence valid?
6 a Accuracy is about how detailed your measurements are. Is your evidence accurate enough to support your conclusion (answer to question 3c)?
b How could you collect more accurate evidence?
7 a Reliability is another way to judge how good your evidence is. Reliability is how sure you are that your results are correct. How reliable is your evidence?
b How could you collect more reliable evidence?
Can You:
> follow a plan carefully
> make accurate measurements
> evaluate your evidence saying whether it is valid, accurate and reliable
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