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Wild About Radishes – 8th Grade Science Scenario, Bethel SD
Wild About Radishes
8th Grade Inquiry Scenario
Original version published by the Science Assessment Team of the Washington Office of the Superintendent of Public
Instruction on September 14, 2007.
Adapted by Bethel School District – March 2012
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
Description: Students investigate the effect of acidity of water on the height that radish plants grow.
Item Description (Performance Expectation
statement from the 8th grade Item Specifications)
2009 WA
Science Std
& P.E.
Item
Type
1
Identify controlled (kept the same) variables in a given
description of a scientific investigation.
INQ – D(1)
MC
2
Identify the manipulated (independent) variable in a given
description of a scientific investigation.
INQ – D(2) CP or MC
B – (acidity; acidity of
water; pH; pH of water)
3
Identify the responding (dependent) variable in a given
description of a scientific investigation.
INQ – D(3) CP or MC
C – (height; height of plant)
INQ – D(5)
MC
A – (reduce number of
factors that could affect
plant height)
INQ – F(1)
SA
< see SA rubric >
LS2 – C(1)
MC
B – (transform light energy
into chemical energy)
Describe that the purpose for controlling variables is to be
sure that an investigation is valid (i.e., the investigative
4 question was answered with confidence; the manipulated
variable caused the change in the responding variable;
alternative explanations for results can be eliminated).
Generate a scientific conclusion using inferential logic and
5 including supporting data given a description of and the
results from a scientific investigation.
6
Describe that producers transform light energy from the
Sun into chemical energy in food through photosynthesis.
Give an example of how science helps solve technological
7 problems (e.g., the science of biology has helped sustain
APP – C(1)
fisheries).
D(1) – Describe whether a given cell structure (i.e., nuclei,
cytoplasm, cell membranes, mitochondria, chloroplasts, cell
walls) belongs to a plant and/or to an animal.
LS1 –
8
D(2) – Describe the function of a cell structure (i.e., nuclei,
D(1),D(2)
cytoplasm, cell membranes, mitochondria) in a given plant
or animal cell.
MC
SA
(two CP)
Explain factors that might influence where the boundaries of
the system can be drawn for the purposes of an investigation
9 to answer the question (e.g., the distance a type of insect
moves during its lifetime might influence where the system
boundaries are drawn).
SYS – B(2)
SA
Describe a plan to answer a given question for a controlled
experiment with the following attributes:
 At least one controlled (kept the same) variable
 One manipulated (independent) variable
10
 One responding (dependent) variable
 Data to be gathered and recorded from multiple trials
 Logical steps
INQ – B(1)
SA
Adapted by Bethel School District – March 2012
Answer
D – (volume of water)
A – (science results [pH]
help engineering design
[soil-watering system] )
Cell wall – (gives stiffness
to plant stem & leaves)
Chloroplast – (changes
light energy into food; does
photosynthesis)
Water – (water is the
manipulated variable)
Air – (air affects plant’s
ability to live & grow)
Light – (plant can’t grow
without light)
< see SA rubric >
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
Wild About Radishes
Directions: Use the following information to answer questions 1 through 10.
Amanda wanted to find out how acidic water affects plant growth. Amanda decided to do an investigation using
radish plants and several water samples with different acidities as measured by pH.
Question: What is the effect of the acidity of water on the height of radish plants?
Hypothesis (prediction): Radish plants given water with a pH of 7 will grow taller than radish plants given
water with a pH lower than 7 because plants will not grow well with water that is acidic.
Materials:
radish seeds
small plant pots filled with soil
water samples each with a different acidity: pH 4, pH 5, pH 6, and pH 7
graduated cylinders
labels
ruler
Adapted by Bethel School District – March 2012
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
Procedure:
1. Label six pots pH 4, six pots pH 5, six pots pH 6, and six pots pH 7 as shown in the Investigation
Setup diagram.
2. Plant one radish seed in each pot.
3. Every three days pour 5 milliliters of water with the labeled pH into each pot.
4. Measure and record the height of the tallest leaf of each radish plant after watering.
5. After two weeks, calculate and record the average plant height for each of the four pH groups.
Data: The table below shows the calculated average plant heights for the six plants in each of the groups.
Acidity of Water vs. Average Plant Height
Acidity of Water
(pH)
Average Plant Height
(centimeters)
4
0.5
5
0.5
6
12.5
7
9.0
Adapted by Bethel School District – March 2012
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
1 Which variable was a controlled (kept the same) variable in this investigation?
o
o
o
o
A. pH of the water
B. Size of the plants
C. Length of the roots
D. Volume of the water
2 Which variable was the manipulated (changed) variable in this investigation?
o
o
o
o
INQ-D(1)
A. Number of plants
B. Acidity of the water
C. Type of seeds in each pot
D. Days for the plants to grow
2 Which variable was the manipulated (changed) variable in this investigation?
Write your answer in this box:
Adapted by Bethel School District – March 2012
INQ-D(2)
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
3 Which variable was the responding (dependent) variable in this investigation?
o
o
o
o
INQ-D(3)
A. Number of seeds planted
B. Time for plants to grow
C. Average plant height
D. Type of water
3 Which variable was the responding (dependent) variable in this investigation?
Write your answer in this box:
4 In this experiment, all of the pots were the same size, shape and material. What is the purpose for
controlling variables like these?
o
o
o
o
A. Reduce the number of factors that could affect the height of the plants.
B. Increase the reliability of the plant height measurements.
C. Increase the reliability of the pH measurements.
D. Make the experiment more like a field study.
Adapted by Bethel School District – March 2012
INQ-D(5)
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
5 Write a conclusion for this investigation.
In your conclusion, be sure to:
 Answer the experimental question.
 Include supporting data from the Acidity of Water vs. Average Plant Height table.
 Explain how these data support your conclusion.
Question: What is the effect of the acidity of water on the height of radish plants?
Adapted by Bethel School District – March 2012
INQ-F(1)
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
6 How does the radish plant get its food energy?
o
o
o
o
LS2-C(1)
A. It absorbs organic material and mineral nutrients from the soil.
B. It transforms light energy into chemical energy in the leaves.
C. It releases gases into the air through openings in the leaves.
D. It transfers water from soil through the roots and stem.
7 Amanda now wants to use the experimental results to help design a soil-watering system for growing
delicious radishes. How does Amanda’s new design project show a relationship between Science and
Engineering?
o
o
o
o
A. The science results about pH help with the engineering design of the soil-watering system.
B. The controlled experiment procedure should be used to design the soil-watering system.
C. They are not related. Science and Engineering are totally separate kinds of work.
D. A scientist solves problems, and an engineer answers questions about systems.
Adapted by Bethel School District – March 2012
APP-C(1)
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
8 Choose two plant cell structures from the list below (structures that only appear in plant cells, not
animal cells). For each cell structure, describe how it helps the radish plants to grow tall:
LS1D(1),D(2)


Cell membrane
Cell wall


Chloroplast
Cytoplasm


Mitochondrion
Nucleus
First Plant Cell Structure:
How this plant cell structure helps the radish plants to grow tall:
Second Plant Cell Structure:
How this plant cell structure helps the radish plants to grow tall:
Adapted by Bethel School District – March 2012
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
9 To help explain the meaning of her
experiment’s results, Amanda made the
simplified system diagram at right.
Choose two of the three system
parts listed below (water, air,
light), and for each part give a
reason why it should be
considered part of the system for
Amanda’s experiment.
SYS-B(2)
LIGHT
RADISH
PLANT
AIR
AIR
WATER
SOIL
In your answer, be sure to:


Choose two of the three system parts (water, air, light).
Give a reason why it should be considered part of the system for Amanda’s experiment.
First System Part:
Why this should be considered part of the system for Amanda’s experiment:
(water, air, or light?)
Second System Part:
Why this should be considered part of the system for Amanda’s experiment:
(water, air, or light?)
Adapted by Bethel School District – March 2012
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
Plan a controlled experiment to answer the question in the box. You may use any
materials and equipment in your procedure.
10
In your procedure, be sure to include:



logical steps to do the investigation
one controlled (kept the same) variable
one manipulated (changed) variable
 one responding (dependent) variable
 how often measurements should be taken
and recorded
Question: What is the effect of different amounts of pH 6 water on the height of radish plants?
Procedure:
Adapted by Bethel School District – March 2012
INQ-B(1)
Wild About Radishes – 8th Grade Science Scenario, Bethel SD
Procedure (continued):
Adapted by Bethel School District – March 2012