MICHELA SACE STAGE 1 FORMATIVE EXPERIMENT DESIGN
‘Effectiveness of solid oxygen bleach in stain removal’
Part A: Experimental Design
VARIABLES:
Independent variable: Water temperature (50, 70 and 90 degrees)
Dependant variable: % stain intensity removed
Variables held constant: amount of bleach, area of stain, amount of water, type of material (cotton), time of soaking.
HYPOTHESIS: The hottest water will remove the most stain from the fabric.
SAFETY: Take care when handling the bleach.
MATERIALS:
- 60g of powdered oxygen bleach
- Scales (to measure bleach)
- 3x Timmers
- 3x Thermometers
- 1L of water
- 3x Kettles
- 1.5L Measuring jug
- 3x small bowels
- 1 cup of recycled coffee grounds
- 1/3 cup measure
- 6x 5L plastic containers
- 3x cotton t-shirts
METHOD:
1. Measure and mark out a square of 15cm by 15cm on each of the cotton t-shirts.
2. Apply 1/3 of a cup of coffee grounds inside the area of each of the squares on the t-shirts, taking care to make sure all of the area is
filled.
3. Prepare a total of three litres of water in the kettle.
4. Meanwhile, measure 20g of the solid oxygen bleach into each of the small bowels.
5. Measure and pour 1 Litre of the water into each of the plastic containers.
6. Add the thermometer to each of the containers. It is recommended that there is a second person to check the temperatures of the
remaining containers of water while step 7 is being conducted.
7. When one of the containers reaches exactly 90 degrees, add the 20g of bleach set aside to the container as well as the soiled t-shirt.
8. Immediately start the timer for 1 hour.
9. When one of the containers cools down to 70 degrees, repeat step 7, ensuring to set a second timer to 1 hour.
10. Repeat for the remaining container when it reaches 60 degrees.
11. While containers are soaking, prepare another three containers with 1L of room temperature water.
12. When the first container has finished soaking, remove the cotton t-shirt.
13. Briefly submerge the t-short into the clean water for 20 seconds to remove the excess bleach.
14. Measure the area of stain removed and calculate the percentage stain the solid oxygen bleach had removed.
15. Repeat steps 12-14 with the remaining t-shirts.
16. Clean up all equipment
Part B: Investigation (done in double lesson)
Part C: Practical Report (see pages 2-5)
, MICHELA SACE STAGE 1 FORMATIVE EXPERIMENT DESIGN
‘Effectiveness of solid oxygen bleach in stain removal’
AIM- To determine the effectiveness of solid oxygen bleach in removing stains
VARIABLES:
Independent variable: Water temperature (20, 30, 40 and 50 degrees)
Dependant variable: % stain intensity removed (colour)
Variables held constant: amount of bleach, amount of stain (3 drops), amount of water (500 mL), type of material (cotton), time of soaking (15
minutes).
INTRODUCTION
Solid oxygen bleach contains the compound sodium percarbonate which is a water soluble, colourless, hygroscopic (absorbs moisture form the
air) and crystalline substancei. Percarbonate is the adduct (sum) of hydrogen peroxide and sodium carbonate and has the chemical formula,
Na2CO3 · 3 H2O2. The compound is less corrosive and is used as an ecofriendly alternative to Chlorine bleachii.
Percarbonate is an oxidising agent which forms hydrogen peroxide (which decomposes into water and oxygen) and sodium carbonate (also
known as ‘soda ash’) in the following decomposition reaction:
Percarbonate sodium carbonate + hydrogen peroxide
iii
Both the hydrogen peroxide and the oxygen work as ‘bleaching agents’ and helps break down the stain into smaller soluble units which can be
removed with wateriv.
The oxygen bleach is added to a container of water. Garments are then added and left to soak for at least one hour. The active ingredient in
solid oxygen bleach (hydrogen peroxide) is activated when dissolved in water. Oxygen bleach will only work properly when the water
temperature is high enough to dissolve the sodium percarbonate v.
As the rate of reaction increases with increased temperature, the water with the highest temperature will be the most effective at removing
stains from the fabric. This is because the oxygen bleach will decompose into hydrogen peroxide faster due to the particles colliding with each
other more. The higher water temperature will have more kinetic energy from the particles thus increasing the rate of reaction with the oxygen
bleach.
HYPOTHESIS: The hottest water (50 degrees) will remove the most stain from the fabric.
MATERIALS:
1. Pipette 5. Measuring cylinder
2. Hot sauce (see figure 1) 6. Scales
3. 3X500mL or larger beakers 7. Thermometer
4. 250mL beaker 8. Kettle
METHOD:
Figure 1- Hot sauce
• Cut a piece of white fabric into 4 equal pieces
• Fill the pipette with hot sauce and place 3 drops in the middle of the 4 pieces of fabric
• Allow to stand for 5 minutes
• Quickly rinse in the beaker of cold water to remove excess stain and record
• Weigh out 1.5g of oxygen bleach powder
• Heat some water using the kettle. Adjust the temperature using cold water until the water is at 20oC.
• Take 500mL of this water and add 1.5 g of oxygen bleach
• Stir with a stirring rod to dissolve all the powder (see figure 2)
• Place one piece of material in the beaker and stir for 15 minutes
• Rinse the material in cold water to remove any bleach and allow to dry. Figure 2- Oxygen
• Repeat the experiment changing the temperature of the solution to 30oC, 40oC and 50oC bleach and 500mL
water
‘Effectiveness of solid oxygen bleach in stain removal’
Part A: Experimental Design
VARIABLES:
Independent variable: Water temperature (50, 70 and 90 degrees)
Dependant variable: % stain intensity removed
Variables held constant: amount of bleach, area of stain, amount of water, type of material (cotton), time of soaking.
HYPOTHESIS: The hottest water will remove the most stain from the fabric.
SAFETY: Take care when handling the bleach.
MATERIALS:
- 60g of powdered oxygen bleach
- Scales (to measure bleach)
- 3x Timmers
- 3x Thermometers
- 1L of water
- 3x Kettles
- 1.5L Measuring jug
- 3x small bowels
- 1 cup of recycled coffee grounds
- 1/3 cup measure
- 6x 5L plastic containers
- 3x cotton t-shirts
METHOD:
1. Measure and mark out a square of 15cm by 15cm on each of the cotton t-shirts.
2. Apply 1/3 of a cup of coffee grounds inside the area of each of the squares on the t-shirts, taking care to make sure all of the area is
filled.
3. Prepare a total of three litres of water in the kettle.
4. Meanwhile, measure 20g of the solid oxygen bleach into each of the small bowels.
5. Measure and pour 1 Litre of the water into each of the plastic containers.
6. Add the thermometer to each of the containers. It is recommended that there is a second person to check the temperatures of the
remaining containers of water while step 7 is being conducted.
7. When one of the containers reaches exactly 90 degrees, add the 20g of bleach set aside to the container as well as the soiled t-shirt.
8. Immediately start the timer for 1 hour.
9. When one of the containers cools down to 70 degrees, repeat step 7, ensuring to set a second timer to 1 hour.
10. Repeat for the remaining container when it reaches 60 degrees.
11. While containers are soaking, prepare another three containers with 1L of room temperature water.
12. When the first container has finished soaking, remove the cotton t-shirt.
13. Briefly submerge the t-short into the clean water for 20 seconds to remove the excess bleach.
14. Measure the area of stain removed and calculate the percentage stain the solid oxygen bleach had removed.
15. Repeat steps 12-14 with the remaining t-shirts.
16. Clean up all equipment
Part B: Investigation (done in double lesson)
Part C: Practical Report (see pages 2-5)
, MICHELA SACE STAGE 1 FORMATIVE EXPERIMENT DESIGN
‘Effectiveness of solid oxygen bleach in stain removal’
AIM- To determine the effectiveness of solid oxygen bleach in removing stains
VARIABLES:
Independent variable: Water temperature (20, 30, 40 and 50 degrees)
Dependant variable: % stain intensity removed (colour)
Variables held constant: amount of bleach, amount of stain (3 drops), amount of water (500 mL), type of material (cotton), time of soaking (15
minutes).
INTRODUCTION
Solid oxygen bleach contains the compound sodium percarbonate which is a water soluble, colourless, hygroscopic (absorbs moisture form the
air) and crystalline substancei. Percarbonate is the adduct (sum) of hydrogen peroxide and sodium carbonate and has the chemical formula,
Na2CO3 · 3 H2O2. The compound is less corrosive and is used as an ecofriendly alternative to Chlorine bleachii.
Percarbonate is an oxidising agent which forms hydrogen peroxide (which decomposes into water and oxygen) and sodium carbonate (also
known as ‘soda ash’) in the following decomposition reaction:
Percarbonate sodium carbonate + hydrogen peroxide
iii
Both the hydrogen peroxide and the oxygen work as ‘bleaching agents’ and helps break down the stain into smaller soluble units which can be
removed with wateriv.
The oxygen bleach is added to a container of water. Garments are then added and left to soak for at least one hour. The active ingredient in
solid oxygen bleach (hydrogen peroxide) is activated when dissolved in water. Oxygen bleach will only work properly when the water
temperature is high enough to dissolve the sodium percarbonate v.
As the rate of reaction increases with increased temperature, the water with the highest temperature will be the most effective at removing
stains from the fabric. This is because the oxygen bleach will decompose into hydrogen peroxide faster due to the particles colliding with each
other more. The higher water temperature will have more kinetic energy from the particles thus increasing the rate of reaction with the oxygen
bleach.
HYPOTHESIS: The hottest water (50 degrees) will remove the most stain from the fabric.
MATERIALS:
1. Pipette 5. Measuring cylinder
2. Hot sauce (see figure 1) 6. Scales
3. 3X500mL or larger beakers 7. Thermometer
4. 250mL beaker 8. Kettle
METHOD:
Figure 1- Hot sauce
• Cut a piece of white fabric into 4 equal pieces
• Fill the pipette with hot sauce and place 3 drops in the middle of the 4 pieces of fabric
• Allow to stand for 5 minutes
• Quickly rinse in the beaker of cold water to remove excess stain and record
• Weigh out 1.5g of oxygen bleach powder
• Heat some water using the kettle. Adjust the temperature using cold water until the water is at 20oC.
• Take 500mL of this water and add 1.5 g of oxygen bleach
• Stir with a stirring rod to dissolve all the powder (see figure 2)
• Place one piece of material in the beaker and stir for 15 minutes
• Rinse the material in cold water to remove any bleach and allow to dry. Figure 2- Oxygen
• Repeat the experiment changing the temperature of the solution to 30oC, 40oC and 50oC bleach and 500mL
water
