Homework for All Grade 7 Classes

Please read section 8.3 "Separating Solutions and Mechanical Mixtures" at home this week. Please complete a note-taking worksheet in your package about the different separation methods.

Rate of Dissolving Lab Due Date

The due date for the rate of dissolving lab is Tuesday April 7th, 2015

Since the lab can be completed in a short time, I would recommend handing it in on Thursday April 2nd to avoid working over the holiday.

Discussion Question for Rate of Dissolving Lab

Please answer the following question in the Discussions section of your lab:

Explain why you observed the results you did? Use your understanding of the particle theory of matter to support your answer.

Lab Report Guideline

 Lab Report Guideline

Problem

What is the experiment designed to find out or demonstrate?

E.g., Will using different amounts of fertilizer affect the growth of plants?

Hypothesis

Write an educated guess as an “if, then,” statement. Be sure to include the independent variable and the dependent variable. An example of this would be:

If a plant receives more fertilizer then it will grow more quickly.

Safety

Provide any safety information that should be followed or safety gear that should be used when performing the experiment; e.g., safety goggles.

Materials and Equipment

Provide a list of all materials and equipment.

Variables

Identify the independent, dependent and controlled variables. A table is a good way of organizing this information.

Variable type	Definition	Example
Independent variable	The variable you are testing (the cause of the change you observe)	The use of different amounts of fertilizer in plants
Dependent variable	The variable that you expect to change (the effect of the independent variable)	The rate at which plants grow with different amounts of fertilizer
Controlled variables	Variables that must be kept the same in order to have a fair test	The amount of sunlight, the amount of water, the type of plant, etc.

Procedure

Make a numbered list of the steps you will need to follow as you perform the experiment. Your goal is to write enough information so you will know what to do, or that someone who has never done this lab would be able to follow your instructions step by step. Point form is acceptable.

 Data and Observations

1. Write a paragraph describing what you observed.
2. Create a table or chart for any data.  
3. Draw at least one picture that shows what you observed. Drawings should always be in pencil and labeled.
4. Create a graph with your data if possible.

Discussions/Analysis Questions

Do some research and answer the following question in this section of the lab:

• Using scientific reasoning, explain your observations. For example, why did the plant that was given more fertilizer grow at a faster rate?

Conclusions

1. Look back at your problem. Was the problem solved?
2. Was your hypothesis correct or incorrect?

Applications

• What specifically did you learn and how can that be applied to your life today or to your understanding of the world.

Sources of Error

Explain any possible errors that may have changed your results; e.g., one of your controlled variables wasn't consistently controlled.

Please note:

a)      You may have the same information as your group members up to and including the observations section. Beyond the observations section, everything is independent (group members should draw their own diagram

b)      Write using only one font and keep the font size to 11-12 point. Calibri font is preferred

c)       Subtitles should be in bold, the lab title may be in 14 point font, however the font style must not change

d)      Any research you do should be cited in a works cited list. Be sure not to plagiarize someone else’s ideas.

Rate of Dissolving Lab Procedures

Procedure #1 - Independent Variable: Temperature

1.       Fill 2 beakers with 200ml of water

2.       Label the beakers “A” and “B”

3.       Heat beaker A until boiling and then remove from hot plate

4.       Use a thermometer to record the water temperature in each beaker

5.       At the same time, add 5ml of granulated sugar into each beaker and begin timing the rate of dissolving

6.       Record observations

Procedure #2 – Independent Variable: Stirring

1.       Fill 2 beakers with 200ml of water

2.       Label the beakers “A” and “B”

3.       Use a thermometer to record the water temperature in each beaker

4.       At the same time, add 5ml of granulated sugar into each beaker and begin timer

5.       Using a straw, stir beaker A once every 5 seconds for one minute

6.       Record your observations

Procedure #3 – Independent Variable: Particle Size

1.       Fill 2 beakers with 200ml of water

2.       Label the beakers “A” and “B”

3.       Heat both beakers on one hot plate until boiling

4.       Use a thermometer to record the water temperature in each beaker

5.       At the same time, add 2 ml of table salt to beaker A and 2 ml of coarse salt to beaker B and begin timing

6.       Record your observations

Hypotheses for Rate of Dissolving Lab

Hypothesis #1 Temperature

 If the temperature of a solvent is higher (higher/lower) then the solute will dissolve more quickly (quickly/slowly) because when the solvent is heated, the particles move faster. These faster moving particles will dissolve the solute more quickly.

Hypothesis #2 Agitation (Stirring)

If the solvent is agitated then the solute will dissolve more quickly(quickly/slowly) because stirring the solvent and solute helps them bump into each other more quickly and therefore dissolve more quickly.

Hypothesis #3 Particle Size

If the particle size of a solute is larger (smaller/larger) then the solute will dissolve more slowly (quickly/slowly) because the solvent particles will only be able to dissolve the outside layer of a larger particle. 

Have a Safe Holiday!

I hope you all have an enjoyable and safe holiday. We will continue with the Pure Substances and Mixtures unit once we return from the break.

Have fun!

Mr. Meles

Homework for all Grade 7 Classes

If your group has already selected your developing nation for our STEM project, you must create 10 questions to guide your research. Please use the Q-chart as a starting point; however, you may create questions that have different prompts than those on the Q-chart.

Engineering Safer Drinking Water Video

Please review this video to help reinforce your understanding of the performance task assigned in class.

Section 8.1 Notes

Solutions: Concentration and Solubility

Solutions

• are homogeneous mixtures
• have the same appearance throughout

Alloys – a special name for solid solutions (e.g., steel)

Solute – the substance that dissolves

Solvent – the substance which does the dissolving

E.g., in sugar and water, the water is the solvent and the sugar is the solute

Water – The Universal Solvent

Water is able to dissolve many different solids, liquids and gases

Not all substances are soluble in water; e.g., fat is insoluble in water

Solubility

Solubility can be defined as:

a)      the relative ability of a solute to form a solution when added to a certain solvent

b)      the maximum amount of solute you can dissolve in a fixed amount of solvent at a given temperature

Forming a Solution

To form a solution, the solute particles must be attracted to the solvent particles; e.g., salt particles are attracted to water particles

We can say that salt is soluble in water because it dissolves in water

Salt and olive oil will not form a solution because the salt particles are not attracted to the oil particles

We can say that salt is insoluble in olive oil because it does not dissolve in olive oil

Concentration – Qualitative

A concentrated solution: A solution that contains a lot of dissolved solute compared to the amount of solvent; e.g., a can of frozen orange juice

A dilute solution: A solution that contains very little solute compared to the amount of solvent; e.g., a solution of water and the can of frozen orange juice

 Concentration – Quantitative

The concentration of a solution can be written as the amount of solute dissolved in a specific amount of solvent.

For example, if 5 grams of salt are dissolved in 500 milliliters of water; the concentration is 5g/500mL

Often we reduce this to a value out of 100mL; so it can be written as 1 gram/100mL

This can also be called a 1 percent solution; this means that for 100mL of solvent there is 1g of solute dissolved in it

Saturation

Saturation: The maximum amount of solute that can be dissolved in a certain amount of solvent at a certain temperature

Saturated Solution: one that has been saturated

Saturation Point: The point at which no more solute can be dissolved in a fixed volume of solvent at that temperature

If more solute can be dissolved into a solvent at a given temperature, then it is called an unsaturated solution.

Sometimes a saturated solution can be cooled below a critical temperature to form a supersaturated solution.

This type of solution contains more solute that would normally be dissolved in the solution.

Additional Grade 7 Science Homework

All students who have yet to read and take notes on section 8.1 (beginning page 211) must do so. This was assigned as class work while I was away at Muskoka Woods last week.

Homework for Next Class

Each student should research developing nations who would benefit from a new technology to help clean drinking water.

Answer the following questions in your research:

1. What are the needs of your nation?
2. Why do you believe this nation needs help?

Be prepared to support your choice to your teammates.

Pure Substances and Mixtures Performance Task Outline

Pure Substances and Mixtures Performance Task

You are a Clean Water Non-Governmental Organization (NGO). Many developed and developing nations are facing a clean water crisis worldwide. You have been approached by the World Health Organization (WHO) to come up with a prototype and a proposal that will solve the water issues in one of these nations.

As a Group:

·                         Decide which country you wish to assist in finding a clean water solution.

·                         Research, plan design and build a device that uses 3 different filtration materials to separate a mystery mechanical mixture that will be provided to you by the WHO

·                         Your device must be able to fit in a 30cm³ box for efficient transportation

·                         You need to use the concepts that you will be learning in class when designing your prototype

·                         Write a reflection about your solution

Please note:

·         It is important to consider the specific geography of the country you are helping when designing your device

·         Keep in mind the environmental, social and economic impacts that your solutions may have

As an Individual:

·                         Research a method to remove the chemical and biological contaminants from a fresh water source

·                         Create a one page report using your research to support your ideas; the criteria for the report will be provided

Assessment

·                         Your device will be evaluated by how much clean water can be filtered in one minute

·                         A list of materials will be made available to your group; each material will have an associated cost – the cost should be considered when designing your prototype

·                         You will also be assessed based on how your design meets the needs of the nation you have chosen to work with

Follow-up to Winnipeg Water Advisory News Reports

Grade 7 Videos for Developing Questioning Skills

This is the second video we watched in class. We developed 10 questions using the Q-chart.

Grade 8 English Homework

Complete filling in the 5-paragraph essay template started in class.

Go to www.mediasmarts.ca

Review the topics about digital and media literacy. Read about topics you are interested in by clicking on the topics.

CTV News Video: Energy-saving bulbs tossed in trash, mercury leaking into environment

Grade 7 Students: In class, we will watch this video and using the Q-chart write 10 questions about the video.

Grade 8 Students: Write a well-formatted paragraph about the video. Your topic sentence should be an opinion and you should be able to find 3 points from the video to support your opinion.

http://toronto.ctvnews.ca/energy-saving-bulbs-tossed-in-trash-leaking-mercury-into-environment-1.2209110