Name___________________
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Science 8
A.
Title and date.
B.
Aim
Design a fair test that will allow you to rank the 5 metals in order from the most reactive don’t to the one that is least reactive.
Design a lab testing the reactivity of the 5 metals, measuring the reactivity by using eyesight to estimate the most vivid reaction represented by fizzing, bubbles, fire or another reaction. The lab will be controlling the surface area ( how much of the material surface is exposed) , temperature, and agitation (. Rank the five metals in order from most reactive to least reactive), when they are combined with hydrochloric Acid. The reactions will be categorized by how powerful their reactions and then thereafter one will find out which is the most and least reactive.
C. Variables.
Variables of Reactivity lab
Identify the variable Changed, Measured, Controlled
Independent Variable
Dependent Variable
Controlled
Variables/constants
The metals (Magnesium,
Alumnium, Copper, Zinc, Iron)
The reactivity
Surface Area
Agitation
How it will be changed?
The metals (1tsp of it as powder) will be changed by physical movement. The metals will be put into each their own test tube, where all the variables will remain the same except the metal.
How it will be measured?
Measure how much time it took for it for dissolve, measured with a stopwatch with seconds. The amount of fizzing, or bubbles as well the speed of it. This will be measured by eyesight.
How they will be controlled?
All of the metals will be in powder form.
How they will be controlled?
There will be no agitation, the test tubes will stay in the test tube rack which won’t be moved either.
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Name___________________
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Science 8
Temperature
Hydrochloric Acid
How they will be controlled?
The temperature will be controlled by using a thermometer. The temperature will be room temperature; there will no touching the test tube (giving it warmth).
How they will be controlled?
There will be 5ml of hydrochloric acid in each test tube; the amount will remain the same for each test tube.
Explanation:
The independent variable in this lab is the metals, Magnesium, Aluminium, Copper, Zinc, Iron. However these are all different metals and have difference such as weight, and flexibility etc. Therefore, in order to make it a fair test and ensure they all have the same surface area and are of the same form, it was decided that they were to be in powder form. This way they will all have almost the exact same surface area, and they will all be standardized. You can get the metals in powder form by either ordering from a supplier online for example http://www.metalpowders.com.au
(Scroll down to the bottom to see citation) or using your own techniques in order to grind the metals to fine powder. By having them in powder form it means your results are much more accurate as well.
The independent variable is the reactivity, the reactivity is going to be measure via eyesight, the way it will be categorized is :
Very strong reaction: Maybe Explosion, fire, excessive fizzing and a lot of rapid bubbling, flows over the test tube
Strong reaction: There are many bubbles fizzing rapidly
Medium reaction: There are some bubbles fizzing, but not at a high speed
Small reaction: There are a few bubbles and a bit of fizzing,
Very small reaction: There is a bit of movement very few bubbles
No reaction visible.
The 3 controlled variables are as following, surface area, agitation and temperature.
Surface area has already been standardized, so that is quite controlled. The agitation just depends on how much you touch the test tubes and how much they are moved or if there was any stirring. In this lab however test tube’s won’t need to be moved so there is no risk of any agitation. The temperature would be the most difficult, because body heat, air around you, heat from your hands, sunlight etc. all these things can affect temperature you just need to make sure you don’t change anything, like you done open the door to the lab halfway. Other than that then the variables in this lab are very controlled and the results should be quite fair as well as accurate.
The reactivity and the levels
Temperature
Agitation
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Science 8
The hydrochloric acid
D. Hypothesis
If you add each of the 5 metals to the hydrochloric acid then according to my knowledge the 2 most reactive metals will be magnesium and aluminium and the 3 least reactive metals will be zinc, iron, and copper because the elements which are closest to the sides of the periodic table are more reactive, since it’s easiest for them to loose or gain valence electron depending on what side they are, which results in them being more reactive. The reactivity would be exposed as movement, strong scents, change of color etc. the more it changes the more reactive
Explanation
All metals react differently, some are seen all by themselves in nature while others are difficult to find just as their own element as they are very reactive and easily create compounds. The reason that magnesium and aluminium are the most reactive is because, take Magnesium for example, it is in the second column meaning that it only needs to get rid of 2 valence electrons in order to have a full valence shell. The elements are reactive according to how easy it is for them to have a full valence shell, for example it’s easier to gain one electron then it is to loose 3. However all metals react differently, and react differently to different elements and compounds depending on their electrons, how they bond etc.
The hypothesis can be tested by looking at how the different metals react. If Magnesium begins to excessively fizz and bubble rapidly whereas iron might just produce a few bubbles then it would be proven correct that, magnesium is more reactive than iron. The reactivity can be measured in many ways, like temperature, the gas output, bubbles etc. We chose to focus on the bubbles/fizzing and the movement in the test tube. For example if the liquid began creating many small bubbles making the entire liquid fizz it would prove the reactivity. Therefore, to prove the hypothesis correct then aluminium and magnesium would have the highest amount of bubbling and fizzing in comparison to the other three metals.
E. Equipment and Materials
5 test tubes
1 test tube rack
aluminium, Magnesium, zinc, iron, copper in powder form (enough for there to be 1 teaspoon
1 teaspoon
1 knife or object with a blade (used to sweep off the metal, so there is exactly one teaspoon)
1 stopwatch
1 measuring cup
30 ml of Hydrochloric acid (5ml for each test tube)
Thermometer
Explanation
The five test tubes for the experiment will be the same size; the same spoon will be used each time.
When doing the materials, remember that there will have be enough for 1 teaspoon, you can get extra if you might be clumsy. The blade used for removing the extra material from the spoon doesn’t have to be a knife; it just needs to be something a thin solid edge which will be able to sweep the material of the spoon smoothly. The stopwatch used, should be using seconds and milliseconds and the measuring cup is for measuring the ml’s.
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Science 8
F. Method
1.
Take out the equipment and materials
2.
Place the 5 test tubes in the test tube rack-
3.
Take the funnel, stick the tip into the first test tube
4.
Measure out 5ml of Hydrochloric Acid with a measuring cup
5.
Pour 5 ml of Hydrochloric Acid into the funnel
6.
Repeat steps 2-4 with all five test tubes
7.
Clean and dry the funnel
8.
Stick thermometer into one test tube at a time and record the temperature
9.
Take one teaspoon of metal powder (this can be any of the 5 metals, there is no order)
10.
Take the teaspoon and take the knife glide over the teaspoon, sweeping away extra material
11.
Be ready with stopwatch
12.
Place funnel into the first test tube and pour the first metal into the funnel
13.
Start stopwatch
14.
Watch the reaction and record the observations
15.
Take a new metal and repeat steps 8-13 and continue till you have tested all 5 metals
Explanation
When you do this experiment you will start by taking out your equipment and your materials. When you place your test tubes, place them in the racket somewhere where there isn’t an AC or a door which might affect the temperature. Also when you have put them in the racket keep them in one place so you won’t be moving it around during the experiment, risking some agitation. The reason there is a funnel is because it will ensure that no material is spilled, and also remember to stick down into the test tube to be completely sure. Afterwards your pour up the acid and then you begin the process of measuring out the metals. However it’s very important that you clean and dry the funnels before you start pouring the metal powder into them.
There might be some residue of the acid left in it, which could cause it to react in the funnel. Then you measure the temperature to ensure it’s all the same.
Measuring out the powder will be done with a knife or something which can sweep away any extra material, that way the amount will be exactly the same for every test tube. As soon as the metal powder has been poured down the funnel, you start the stopwatch. Now you begin recording the data according to the reactions, “very strong reaction, strong reaction, medium reaction, small reaction, very small reaction and no reaction visible”
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Science 8
G. Diagram of apparatus
Diagram of Reactivity lab
Explanation
Here it shows the setup of the experiment, you see the funnel and the teaspoon above it. The teaspoon is pouring metal powder into the funnel leading it down into test tube with 5ml of Hydrochloric acid. The stopwatch is on the side for the other person to start and stop, recording the time for the metals to dissolve.
The thermometer is there as well, in order to check the temperature before adding the metal powder, in order to make sure that it is a fair test and that all the temperatures are the same.
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Science 8
Part two of lab
H. Presenting Data – Qualitative Observations
Aluminum
Magnesium
Iron
Zinc
Trial 1
After 30 seconds there is no visible reaction. The aluminium just floats on top of the acid. There are droplets of acid that sit on aluminium.
No change at 2min.
Stopwatch stopped at 2 min.
There is Immediate rapid fizzing and many small bubbles, the liquid is unclear with bubbles. The bubbles are jumping out, at about 1-2 cm, there is also some smoke rising slowly. After 8 seconds the acid reacts with the metal in a visible way,
The black, on the metal turns more silver. At 1 min there is condensed liquid on the sides of the container.
At 1.20 it smells like beer and smoke.
At 2 min bubbles are smaller and the acid becomes clearer, the bubbles aren’t rising as fast.
Stopwatch stopped at 2 min.
There is no immediate visible change. There are little bubbles at 45 sec. the Bubbles are a bit larger 2 min.
Stopwatch stopped at 2 min.
on the face of it.
After 10 seconds there are small bubbles on the edges of the piece of zinc. After 30 seconds the bubbles grow larger and they begin appearing
Stopwatch stopped at 2 min.
Trial
After 10 seconds the acid turns pink.
The aluminium just floats on top of the acid. There are droplets of acid that sit on aluminium.
No change at 2min, the acid is still a slight pink shade, however the acid is clear.
Stopwatch stopped at 2 min.
There is Immediate rapid fizzing and many small bubbles, the liquid is unclear with bubbles. The bubbles are jumping out, at about 1-2 cm, there is also some smoke rising slowly. After 8 seconds the acid reacts with the metal in a visible way,
The black, on the metal turns more silver. At 1 min there is condensed liquid on the sides of the container.
At 1.20 it smells like beer and smoke.
At 2 min bubbles are smaller and the acid becomes clearer, the bubbles aren’t rising as fast.
Stopwatch stopped at 2 min.
At 50 sec there are small bubbles, which have appeared. At 1.30 some of the bubbles begin to rise. Bubbles are getting larger at 1.50
Stopwatch stopped at 2 min.
After 10 seconds the acid turns a clear light pink color. There is fizzing and bubbles rising from the piece of zinc at 40 sec .Big bubbles appear at the bottom of the container, and rise up at a medium speed. There is smaller bubbles on the surface of the metal piece at 1 min.At 2 min bubbles are still fizzing
Copper The metal turns pinkish, when the acid reacts with it. The acid gets a light brown color. There are little brown particles in the edges of the
Stopwatch stopped at 2 min.
The metal turns pinkish, when the acid reacts with it. The acid gets a light brown color. There are little brown particles in the edges of the
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Name___________________
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Science 8 container. After 20 seconds there isn’t much visible change. container. After 40 seconds the copper has a lighter colour.
Stopwatch stopped at 2 min. Stopwatch stopped at 2 min.
I.
Interpret data
Visual representation of qualitative data of the reactivity of the metals mixed with Hydrochloric Acid.
J. Conclusion
The Hypothesis – “If you add each of the 5 metals to the hydrochloric acid then according to my knowledge the 2 most reactive metals will be magnesium and aluminum and the 3 least reactive metals will be zinc, iron, and copper because the elements which are closest to the sides of the periodic table are more reactive, since it’s easiest for them to loose or gain valence electron depending on what side they are, which results in them being more reactive. The reactivity would be exposed as movement, strong scents, change of color etc. the more it changes the more reactive”
According to the qualitative data Magnesium and zinc were the two most reactive metals; both of them produced many bubbles, they fizzed when they came in contact with the acid, the least reactive was iron, copper, and aluminum, some of them just produced some bubbles. The acid turned pink though when it came in contact with the copper, but it did that with zinc as well on the second trial, which was very strange and unexpected. An empty small container had some acid poured into to test whether it was the metal reacting or if it was some residue chemical from the container. The empty container’s acid turned pink so it was concluded that it was the container which had leftover chemicals, leading it to turn pink, so the color change wasn’t included when looking at which metal was most reactive. The original hypothesis was half proven correct, magnesium was the most reactive. Aluminum nonetheless, wasn’t visibly reactive; it just floated on top of the acid, there was no change which could be seen with the human eye. The zinc however, had some bubbles and some fizzing, which proved the hypothesis wrong; it was more reactive than aluminum and some of the other metals. Zinc has 2 electrons in the outer orbital, which means it is easier for it to get rid of electrons rather than gaining, it was also centered in the middle meaning it should be less reactive according to the knowledge which I already have. A theory could be that the aluminum which was used had been treated with chemicals or some
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Name___________________
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Science 8 sort of preservatives, which decreased the speed at which it reacts with other elements and compounds, such as the acid, which would be why it wasn’t as reactive as expected (Since It was household foil).
K, Evaluation
The method which was used to mix the metals with hydrochloric Acid was different from the one which was written in this lab.
Instead, the metals were in different shapes, and they were put into different small containers one trial by one, each in a different container. There was hydrochloric acid drops, dropped into each container, there was about 20 – 30 drops. The metals had different surface areas, as well as there were different amount since some of the metal pieces were larger than other when they were received. The time period in which mixture was observed was 2 min, observations were recorded during this time.
The validity of the method-
The method which was used wasn’t very accurate, it had several weaknesses and changed many variables.
It changed the volume, weight, metal and surface area, which is much more than only 1 variable; there could definitely be improvement to the method. There were no specific directions to how much of the metal was needed, so the amounts were estimated by eyesight. The trials were repeated only 2 times, it could have been more trials in order to get a more accurate results, since for example Zinc it didn’t fizz the first time but it fizzed the second time. If there had been a third trial one could determine which one was the accurate reaction.
The validity of the hypothesis-
The hypothesis was testable, the reactivity could be “measured” by observing the acid and the metals, the more rapid movements, and the bigger the difference was from there not being any change at all (by it just being the metal and the liquid, seeing no change in the acid or to the metal). After comparing all the observations, one could conclude which had the biggest changes to which had no change at all. The hypothesis was valid and testable, it included the independent and dependent variable as well as had qualitative values which could be subjected to testing and measured.
Weakness
The surface Area –
The surface area each of the metals was different which didn’t make it a fair test. It could have interfered with the reactivity of it.
Improvement
Next time, all the metals should have standardized the surface area one way or another. One possibility could be to order each of the metals from a company where they all have the same size, shape and surface area, a small square? Another way could be powdering each of the metals, that way they will have
The amount of the metal –
For each metal there was a different volume, meaning that the ratio to acid was different which could have impacted the reactivity. almost exactly the same surface area.
The amount of metal can be measured by volume; in the original method it showed a way to do this. Using a spoon and scraping of the top so there is an equal volume among the metals. Many other methods can be used, small cups, small containers etc. As long as the method is consistent and measures the same volume each time.
The cleanliness of the container can be improved in several Cleanliness of container –
The cleanliness of the container is known for a fact to have interfered. The container has left over chemicals which reacted with the acid by showing a pink color. There might have been other chemicals which impacted other metals, maybe prevented them from fizzing etc. It didn’t make it a fair test. ways. One could be to use a completely new one, in order to insure there is no residue, as well as diluting it with water for some time as preparation. Another method is testing the container to check whether there is still acid. In general remember to clean all containers thoroughly as well as test them before proceeding an experiment.
Due date of Part two 5/9/2013
Citaitions:
"Australian Metal Powders Supplies (AMPS)." Australian Metal Powders Supplies. AUSTRALIAN METAL POWDERS
SUPPLIES PTY, n.d. Web. 13 Mar. 2013.
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i.
ii.
iii.
iv.
v.
Name___________________
Date____________________
Science 8
Criterion C: Processing and evaluating
Maximum: 8
Students should be able to: present collected and transformed data interpret data and describe results using scientific reasoning discuss the validity of a hypothesis based on the outcome of the scientific investigation discuss the validity of the method explain improvements or extensions to the method.
Achievement level
0
Level descriptor
The student does not reach a standard described by any of the descriptors below.
1 - 2
The student is able to: i.
ii.
iii.
iv.
v.
collect and present data in numerical and/or visual forms accurately interpret data state the validity of a hypothesis based on the outcome of a scientific investigation state the validity of the method based on the outcome of a scientific investigation state improvements or extensions to the method.
3 - 4
5 - 6
The student is able to: i.
ii.
iii.
iv.
v.
collect and present data in numerical and/or visual forms correctly accurately interpret data and describe the results outline the validity of a hypothesis based on the outcome of a scientific investigation outline the validity of the method based on the outcome of a scientific investigation outline improvements or extensions to the method that would benefit the scientific investigation.
The student is able to: i.
ii.
iii.
iv.
v.
collect, organize and present data in numerical and/or visual forms correctly accurately interpret data and describe results using scientific reasoning describe the validity of a hypothesis based on the outcome of a scientific investigation describe the validity of the method based on the outcome of a scientific investigation describe improvements or extensions to the method that would benefit the scientific investigation.
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Science 8
7 - 8
The student is able to: i.
ii.
iii.
iv.
v.
collect, organize, transform and present data in numerical and/or visual forms correctly accurately interpret data and describe results using correct scientific reasoning discuss the validity of a hypothesis based on the outcome of a scientific investigation discuss the validity of the method based on the outcome of a scientific investigation explain improvements or extensions to the method that would benefit the scientific investigation.
Due date of Part two 5/9/2013
Criterion B: Inquiring and designing
Maximum: 8
Students should be able to: i.
ii.
iii.
iv.
describe outline a testable hypothesis and describe design
a problem or question to be tested by a scientific investigation
how to manipulate the variables, and
scientific investigations.
Achievement level explain it using reasoning describe how data will be collected
Level descriptor
0 The student does not reach a standard described by any of the descriptors given below.
1 - 2
3 - 4 i.
ii.
iii.
iv.
The student: attempts to state a problem or question to be tested by a scientific investigation is able to state a testable hypothesis is able to state the variables attempts to design a method. i.
ii.
iii.
iv.
The student is able to: state a problem or question to be tested by a scientific investigation outline a testable hypothesis using scientific reasoning outline how to manipulate the variables, and state how relevant data will be collected design a safe method in which he or she selects materials and equipment.
5 - 6 i.
ii.
iii.
iv.
The student is able to: outline a problem or question to be tested by a scientific investigation outline and explain a testable hypothesis using scientific reasoning outline how to manipulate the variables, and outline how sufficient, relevant data will be collected design a complete and safe method in which he or she selects appropriate materials and equipment.
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Name___________________
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Science 8
7 - 8 i.
ii.
iii.
iv.
The student is able to: describe a problem or question to be tested by a scientific investigation outline and explain a testable hypothesis using correct scientific reasoning describe how to manipulate the variables, and describe how sufficient, relevant data will be collected design a logical, complete and safe method in which he or she selects appropriate materials or equipment.
Command terms
Describe Give a detailed account or picture of a situation, event, pattern or process
Design
Explain
Produce a plan, simulation or model
Give a detailed account including reasons or causes
Outline
State
Give a brief account
Give a specific name, value or other brief answer without explanation or calculation
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