Tensai Lab provides an opportunity for Junior high school students to learn about the purpose of conducting research, how to conduct research and most importantly, how to be safe while conducting experiments.
Scientists make plans to guide them on how they will conduct an experiment to solve a probem or to learn something new. Their plan is called the scientific method. Scientists might not use all the steps, or they might do the steps in a different order.
A variable is something that can change, and could influence the outcome of the problem a scientist is investigating.
The variable that changes in an experiment is the independent variable. Most experiments test only one independent variable at a time. Which means the other variables that can influence the experiment should be controlled so that they do not influence the results and mess up the things we measure.
An experiment is a scientific test that can be used to support or disprove a hypothesis.
Think of a natural area such as a ravine, forest, a river etc, where you like to visit. Think of the various human activities that occur there. For example, people may be using it for physical exercises like jogging, others could be using it to walk their dogs, to fish, or agriculture etc. Think of how these human activities could negatively impact the natural environment such as too much litter, interferance with wildlife and vegetation etc. Work with a friend, select 4 or five of these negative impacts and write a one-pager summarizing these impacts. Include why you think this is impactful and what measures can be taken to prevent/reduce the negative impact.
Explain how the following individuals impact their environments.
Look around your classroom to find as many biotic (living) and abiotic (non-living) factors as possible. Make a table to list these factors. You can Work with a partner or in groups as you wish. Compare your table with those of other groups. As you compare with other groups, you can add any missing factors to your table.
Indicate using arrows, the interactions between the biotic and abiotic factors. For example, if you have a potted plant in your classroom, you can indicate that the plant interacts with soil, air, light and water etc. The students (biotic factors) also interact with the same air. Use arrows to connect the factors that interact.
Create a table with three columns. On the left column, make a list of several different types of packaging/containers used for various drinks. In the middle column, write a list of the Pros (advantages/positive attributes) associated with that packaging type. In the right column, write a list of all disadvantages (Cons) or negative attibutes associated with that packaging. The pros and cons may include (but not limited to) cost, availability, environmental impact, energy, recycling etc. As a group, determine which material would be best, or would have the least negative impact on the environment. Justify your choice.
Prepare a presentation to give to your class about the process you utilized in your group to choose the packaging material with the least environmental impact.
This of three foods you ate in the past 24 hours and write them down. Now draw an arrow on the left of each of the foods you listed and write where that food came from. Then draw another arrow on the left and indicate where that food also came from. You can have multiple arrows pointing at the same food item if its made with multiple ingredients.
What did you list as the very last food source for each food item on your list? What is common among all the food items you listed?
Creating a food web and food pyramid
List about 15 different organisms you can think of. Now draw an arrow indicating the transfer of energy from one individual to another. The arrow should point at the animal to where the energy is transferred to, for example, an arrow from kale to a rabbit indicates that kale 'is eaten by' rabbits and so energy is transferred from kale to the rabbit.
You can then transfer your information to a different sheet of paper. Aim to create a more organized looking food web so begin at the bottom of the paper listing all the organisms on your list that are producers. Producers are plants that utlize energy from the sun to create their own energy. Abive the producers write the primary consumers; organisms that feed on producers, such as rabbits, sheep, grasshoppers, etc. continue to create layers including secondary consumers, tertiary consumers until you get to decomposers.
Food web in action (group activity)
Work in groups of about 8 or more individuals. Let each person in the group pretend to be a different organism. Create labels using stickers for each organism in the group, for example, grass, spinach, rabbit, grasshopper, rat, frog, snake, lizard, hawk, owl, sheep, humans, bacteria, mushrooms etc. The group should stand up and make a circle. Give each producer in the group (plants) a ball of string. While holding on to one end of the the string, the organism should pass the ball to another organism in the group to whom energy can flow to. For example the organism labeled grass can pass the ball to the organism labeled rabbit or grasshopper. The organism then holds that section of the string and pass the ball ahead to the next organism where energy can flow to. For example, the rabbit could pass the ball to the hawk.
This is a group activity. you need an odd number of about 9 people, minimum 5 people. One person will be the recorder and the rest will be the population. Half of the group is given forks and the other half is given spoons. The recorder will place several 'food items' on the floor/ground/field. Food items can include tooth picks, tennis balls, boiled eggs, ball of yarn, erasers etc. The group will line up with their forks and spoons. On the ring of a bell or a whistle, the group is given 30 seconds to go to the area where the food items have been placed and ensure they pick at least one food item using ither the fork or the spoon they have. AFter 30 seconds all individuals stop and go back to the recorder who records every individual that has collected at least one food item. Anyone in the group who does not have a food item is eliminated from the game.The recorder will replace some of the food items back to the area but not all of them. The individuals remaining in the game will again have 30 seconds to pick at least one food item. This may be repeated until there is either no food item remaining or all individuals have been eliminated.
You can look at the fork and spoon as differences in adaptations among the individuals that allow them to be able to obtian certain food items better than others. The game should be such as whatever food items you chose provide almost equal opportunities for the spoons and forks to survive. If you notice that there are no individuals being eliminated, you can reduce the time from 30 seconds to 20, or even 15 seconds and test the game again. You could also reduce the amount of food items available.
How did the competition affect the number of individuals or populations in the ecosystem?
A. Water use
You can calculate your water use for a specified amount of time by adding up all the various ways you utilize water. For example, you drink about 2 L of water a day, You use about 30 L of water to shower, 2 L to brush your teeth, 30 L to wash your dishes after eating, You flush about 20 L in the toilet per day etc. Make a list of all the ways you utilize water and provide an estimate of how much water you use per day.
B. Waste disposal
There are four categories of waste to consider: organic (will decompose), inorganic (will not easily decompose), items to be reused or recycled, and miscellaneous. In this activity, you will determine how much waste you generate in a day.
C. Goods and services purchased
Make a list of everything you purchased in the last week. Include food items. Determine the approximate total cost of these items to obtain an estimate total expenditure per week. Identify items on the list that could be classified as non-essential, then recalculate your total cost for the week, so that you have two totals: one for essential items and the other for non-essential items.
The idea of the ecological footprint was developed to help people understand why they need to find a sustainable lifestyle. Research online to find out what a sustainable lifestyle is.
Obtain 4 plant cuttings. In one cutting, remove all the leaves. In the second cutting, remove the leaves and leave only one healthy leaf on the cutting. In the third cutting, remove half of the leaves leaving the other half on the cutting. In the fourth (last) cutting, leave all the leaves intact.
In 4 separate beakers, add 30 mL of water into each beaker, being careful to ensure each beaker has exactly 30 mL of water. cover the top of the beaker with clear plastic wrap. Make a small hole on the plastic wrap just enough to pass the cutting though it.
Place the beakers (containing the cuttings) near a sunny window or outside for two days (about 48 hours).
Remove the cuttings and transfer the water into a measuring cylinder and record the amount of water left in each beaker.
For each cutting, remove the leaves and trace them on a squared paper. use the squares to estimate the surface area of each leaf. Add up the surface areas for the leaves in each beaker and record that number in the same table you recorded the volumes of water.
Draw two bar graphs, one showing the volume of water for each of the 4 beakers, and the other showing the surface area of the leaves corresponding to each beaker.
Is there a relationship between the number of leaves you left on the cuttigs and the surface area of the leaves as counted on the squared paper? What do you observe as the relationship between the leaf surface area and the volume of water remaining in the beaker?
Think about the following agricultural practices:
Are the benefits/consequences of the practices the same? Are you able to sort the practices from the least beneficial to the most beneficial? Are there practices you were uncertain about their net impact?
Create a classification key that will distinguish between five different varieties of a plant. The classification criteria must must distinguish each of the varieties by at least one unique trait and must be clear and easy to use.
Share your classification key in your classroom and compare it with those of your classmates. Did everyone use the same traits? Was the visual tool that others used more or less effective than yours?
Obtain an ice cube from an adult of from your teacher in class. You will need to melt this ice cube in the fastest way possible, following these instructions.
You must only use whatever is on or at your desk right now.
You must keep and collect as much of the melted ice as possible.
Do not put the ice cube in your mouth
Use a stopwatch to record the time it takes to competely melt the ice cube.
What strategies did you use to melt the ice cube?
If you could do this activity again, what would you do differently? Why?
If the rules changed to allow you to use anything to melt the ice cube, what would you use? How do you think that might change your results? Why?
Obtain a plastic bag such as a garbage bag. Ensure there are no holes, or seal them. Use a tape or paper clips to seal a part of the opening and leave an opening of about 10cm in diameter. Spread the paper clips evenly around the opening. Use a hair dryer with its nozzle pointing upwards and swith it on to its highest heat setting. Gently position the open end of the platic bag over the hair dryer about 10 cm away from the nozzle. Hold the bag in place until it appears to be full of hot air. Turn off the hair dryer and release the bag. What happens?
Using only a sheet of paper (roughly the size of a page from your notebook), design a structure that will rest between the two stacks of books and support the can of pop. You have 5 min to work on your design at your desk. You will then get a chance to put your structure to the test on the set-up at the front of the class.
You can try multiple designs just use only one paper each time.
1. Tie 4 long skewers together about 2–3 cm from the end of each skewer. Splay them out in 4 directions to make a base and stand the structure on a non-skid mat. Wrap the frame with plastic.
2. Tie 2 short skewers and 2 long skewers together, about 2–3 cm from the end of each skewer. Splay the skewers out and set the structure on the second non-skid mat so that the 2 short poles are at the NW and SW positions. Wrap the frame with plastic wrap.
Place a fan about 50 cm away from the teepees at the NW position. Turn the fan on high. How do the teepees respond to the force?
Which of the 2 teepee designs is more stable?
Research the material composition of a plant or an animal of your choice. Make a list of some of the materials that can be found in the organism you chose. Find out what properties these materials have and what advantages these give the structure in terms of how it functions. How are the parts of the structure in your chosen plant or animal are joined?. Present your findings and include drawings where possible.
Think about the several backpacks you have used since you started school. List the things that you would have changed to make the backpacks more comfortable, user friendly, last longer, stronger/able to carry heavier items, optimal size etc.
Now design the perfect backpack and indicate the reason for the different components you have incorporated into your design.
In this activity, you will make your own fossil mould and cast. You can use seashells or other small objects that have an interesting texture to make your fossil.
Apply petroleum jelly on the outside of the sea shells.
Mix up about a cup of plaster of Paris and water in a small bowl so that it looks like thick cream. Add food colouring, mixing well
Slowly pour the plaster mixture into a plastic cup until it is about 3 cm from the top. Press the seashell, greased side down, into the wet plaster. Leave overnight.
Remove the shell the next day. The coloured plaster is the fossil mould. Coat the entire surface of the plaster mould with petroleum jelly.
Mix up a new batch of plaster of Paris, but this time don’t add food colouring. Pour the plaster onto the mould so that it fills the cup.
The next day, carefully separate the two plaster pieces. Examine the coloured mould and the white cast.
Science research begins with a Question asking why something behaves the way it does, or what would happen if something was introduced into a system, how a system would respond to change. Science research is aimed at creating new knowledge.
Hypothesis: Researchers create a hypothesis regarding around the research question. A hypothesis is a possible explanation for the observation. For example, if the question is, Is bird migration associated with changes in weather patterns in their habitat? A hypothesis will be something like: Weather patterns influence the migration of birds from their habitats.
You can also design a hypothesis using the If....then...because structure. If the weather changes, then the birds will migrate because they need to find a more suitable habitat.
To be valid, a hypothesis must be testable.
Experimental Design
Researchers design controlled experiments to test the hypothesis. This means that all variables (conditions) must be kept the same (controlled), and only the one variable that is being tested for is allowed to vary.
The study population is randomly divided into a control group and an experimental group.
The control group allows the researcher to compare the test results with a group that has not been exposed to the experimental variable, but all other conditions remain the same.
The experimental group gets the variable being tested for while all other conditions remain the same as the control group.
Independent Variable – The variable that is controlled by the experimenter/researcher, or the variable that changes and influences the response variable (dependent variable).
Dependent Variable or Response variable – The variable that is measured in the outcome of the experiment. The variable that we hypothesize that it will be influenced if the independent variable changes.
Lets assume we are researching the impact of high carbohydrate levels in feed on milk production in dairy cows. We develop a Low carbohydrates diet of about 5% (which will act as our control) and a high carbohydrate diet of about 50% (which is the diet we want to test, so, the treatment). Remember the diets and the control vs treatment groups are determined by the research question. In this case, the question is, will high carbohydrate levels influence milk production? so we are just testing one high carb diet. A different research question such as..do carbohydrate levels influence milk production? would require us to create different treatments and controls.
Data collection: The same data should be collected in both the treatment and the control groups. The data can be recorded in many different formats such as tables, tallies, counts, and even images. You need to think about the methods you will use to analyse the data as this will then influence what data needs to be collected. The data should be able to answer the question you started the experiment with. In the example about, we will collect milk production data, which is the volume of milk produced per animal per day. Ideally, we can collect this data even before exposing the animals to our treatments. The treatments will then be initiated at the same time in the experimental and the control groups. and data collection will continue for the time period of the research. Some of the decisions a researcher makes may be informed by other research reports or information about the underlying effects of the variables. For example, for how long should the researcher collect milk production data? Remember if the groups are uniform, (most variables have been controlled), it is easy to associate the changes in milk production to the treatments. But we also know that because the carbohydrates have to undergo metabolism to the extent where they can affect milk production, we have to give them sufficient time to have this impact. This means we may not be able to detect true effects in the first 3 days of introducing the diets, but we may also not observe significant changes after 6 months. The researcher should decide the critical time period that they would like to observe the effects of the diet.
Data can be both qualitative and quantitative. Qualitative data includes observations such as high, low, tall, short etc. Quantitative data includes measurable numbers such as 2 L of milk, 160cm tall, etc.
Data analysis and visualization: The goal of data analysis is to test the hypothesis. Data recorded as numbers on a table may be more difficult to 'see' so various methods of data visualization can be used to convert numbers into images that can be easier to interpret. For example, we could use a graph that expresses the milk production during the research period. We could go further and develop two graphs showing the milk production of the group that got high carbohydrates and the milk production of the group that received low carbohydrates. This way it will be easier to visualize the differences between the two graphs.
Conclusion: State the results you have obtained from the study. Indicate whether the hypothesis was supported or rejected. Also show how the results lead you to decide whether your hypothesis was supported. Mention any errors that could have been made that would have affected the results. Provide suggestions for improvement in experimental design in future. This is mostly based on the results you got and the limitations you observed in your experimental design. Lets say for example you notice that the carbohydrate levels in the feed affected how much feed the animal consumed. Especially if the high carbohydates resulted in animals consuming less feed, while the low carbohydrate group seemed to consume more feed. This would indirectly affect how much carbohydrates enter the animals metabolism and skew the milk production data. You may therefore recommend that future researchers should regulate how much feed is given to the animals and ensure each animal consumes all the provided feed.
Lab safety rules and symbols are needed to guide students and prevent injuries. You have reveiwed several lab safety tips in previous classes. Here is a summary just to remind you of some key rules.
Keep your workspace tidy. Put apparatus away if you are done using the.
Spontaneous generation was theory proposed in the 16th century when it was proposed that Living things would develop from non-living things. People observed maggots and flies appearing from rotting meat or mice appearing from stacks of hay and proposed that these organisms would develop spontaneously. This theory was considered true for over 200 years until the 18th century when researchers sealed meat into a jar and observed that maggots and flies did not appear unless the meat was exposed where flies would lay their eggs on the meat.
Several studies have been conducted wrongly and led to wrong results and conclusions. One of the most common errors in research has to do with what is called stratification. Remember we mentioned previously that the assignment of treatment and control groups has to be completely random so that there will be no any other variable that may influence the response variable except the variable being tested. Consider the example of carbohydrate levels on milk production. Imagine if the animals that received low carbohydrate in their diets were Jersey cows and the ones that received high carbohydrates were Friesian cows. This would be a startified population because all the animals receiving the treatment already have one thing in coomn (they fit into one strata). The differences in milk production you observe may be due to the diet, but may also be due to inherent differences in the two breeds of cattle. These results are said to be confounded.
Is the black ink in a marker pen a pure substance or a solution?
Experiment Procedure:
What did you observe? Is the ink in a marker a pure substance or a solution? Support your answer with your data
Your teacher will provide you 3 different substances, which may include sugar, salt and powdered drink crystals. Use the graduated cylinder to measure 50 mL of water into a beaker. Measure 5 g of one substance. Add this to the water. Stir the mixture until the substance has dissolved. Record your observations in a table. Keep adding more of the same substance to the water, 5 g at a time, until no more will dissolve. Record how many grams you added to achieve this saturation point.
repeat these steps for the rest of the substances, recording the amount of substance that the water could dissolve before reaching saturation.
How did you know when the solution was saturated?
Calculate the concentration of each solution in grams per 100 mL. Don’t forget you used only 50 mL of water, so you will need to adjust the mass and volume.
Your teacher will provide juice drink crystals, petroleum jelly, sugar, and salt as solutes, and water and vegetable oil as solvents.
Your task is to identify which solutes dissolve in which solvent. Add water in 4 beakers and vegetable oil in 4 other beakers. then add one solute in each beaker containing water and repeat for the beakers contianing vegetable oil.
Which solutes dissolved in water and which solutes dissolved in the vegetable oil?
In this activity, you will observe the effect of temperature on the solubility of sugar and salt. Prepare a saturated solution of sugar and salt so that you can observe undissolved solute particles. Under the suprvision of an adult or your teacher, gently heat the solution and continue to stir gently. What do you observe? Continue adding each solute and stir as the solution continues to heat and record your observation. Did you get to a point where no more solute would dissolve even at a higher temperature?
A supersaturated solution is one that contains more solute than it normally would be able to dissolve at a certain temperature.
Pour 50 mL of water into one beaker, 50 mL of rubbing alcohol into another beaker, and 50 mL of vinegar into a third beaker. Label the beakers. Mark each piece of fabric with mud, lipstick, and chocolate. Place one piece of soiled fabric into each beaker. Swirl the fabric around in each solution using the forceps. Leave for at least 10 min. Look at the stains. Add some laundry detergent to the beaker containing water. Use the forceps to swirl the fabric around in the solution. Leave for at least 10 min. Look at the stains.
Did the mud dissolve in each solvent? Did the lipstick dissolve in each solvent? Did the chocolate dissolve in each solvent? Did the detergent help the water dissolve the stains?
Which substances would you recommend to include in a cleaning agent?
Set up your microscope and obtain a prepared slide of plant cells, and place the slide on the microscope stage and hold it in place using the stage clips. Make sure the low-power objective lens is above the slide and start observing through the eye piece. Use the coarse adjustment knob to bring your specimen into focus. Then use the fine adjustment knob to get a clear, sharp image.
Gently move the glass slide left and right to observe different areas of the slide.
Record your observations. You may draw the cells if necessary. Be particularly keen to the shape of the cells, their arrangement and the organelles. Count or estimate the number of cells you observe in the field of view.
Remove the slide and place the animal cell slide provided your teacher and repeat the process as you did for the first slide.
What are some of the striking differences you noticed between the plant and the animal cells?
Prepare a wet mount of a small piece of onion skin. Position the skin as flat as possible on the slide. Place the slide under the microscope and draw one or two of the cells you observe. Remove the slide and place several drops of saltwater solution on one side of the cover slip. Use a piece of paper towel to 'pull' the saltwater solution under the cover slip. Wait for about 60 seconds and then place the slide under the microscope again to observe. Once again, draw one or two of the cells you observe.
Repeat these steps using distilled water and observe under the microscope again.
1. Diffusion
Obtain three jars or beakers. In one jar, add cold water. In another jar add warm water and in the third jar add hot water. Be careful when handling hot water and please ask an adult for assistance if necessary to avoid burns. In each jar, add a tea bag and wait for one minute as you observe what happens. After one minute, remove the tea bags and place them on a paper towel. Which jar change color the most? Did you notice how fast the color change occured? Why do people use a spoon to stir tea bags or sugar when making tea or coffee?
2. Osmosis
a. Obtain two jars. In one add plain water and in another add a concentrated sugar solution. Add dry raisins in both jars and leave them for 30 minutes. Remove the raisins and observe the changes.
b. Your teacher will provide you pieces of a tube made using an semi-permeable membrane. Tie one end of each tube tightly with a string. Add equal amounts of concentrated sugar solution into the tube and then tie the other end. Obtain two jars and in one add plain tap water and in the other tube, add the same concentrated sugar solution. Place a tube in each of the jars and leave for 30 minutes, then remove the tubes and observe.
Did the volume of the solution inside the tubes change? Was there a change in both tubes? How can you explain this change?
At the beginning of your gym class, your teacher will select 4 students to and apply a ultraviolet dye on their hands. Students will be allowed to go to the gym for their gym class as usual. When they return to class (within an hour of application), the teacher will switch off the lights and use a UV light. shine the UV light on each student one at a time to detect if they have contacted the UV dye. All students that have traces of the UV light will be asked to stay in one side of the class.
How many students tested positive for the UV dye? What is this proportion of positives in the class?
Use a pin to make a tiny hole in the centre of the bottom of a cup. Place a piece of wax paper over the open end of the cup using a rubber band to hold it in place. Turn off the lights in the room and point the end of the cup with the hole toward the light bulb. Look at the image formed on the wax paper.
Place the lens in between the stand and the lit bulb. Move the screen and the bulb slowly inward, then outward, keeping the lens in the middle. At a particular distance, an upside-down bulb of the same size as the actual bulb will come into focus on the screen. This might take some time so be patient and keep trying. Measure the distance between the bulb and lens. Divide this value by 2. This is the approximate focal length of the lens.
Shine a light through a glass prism so that the light leaving the prism falls on an unlined piece of paper. What colours do you see? As you hold the prism and light steady, your partner will use coloured pencils to draw the colours on the piece of paper. Switch places with your partner. Again, trace the colours you see onto the piece of paper.
Was it difficult to see where one colour ends and the next begins? Did the order of the colours on the paper ever change?
Your teacher will provide you with a variety of materials and two light sources: a regular bulb and a black light bulb. The regular bulb emits infrared radiation (heat) as well as light. The black light bulb emits mostly ultraviolet light. Darken the room as much as possible and turn on the regular light bulb. Hold the materials up to the light and observe the appearance of each material. Repeat the process using the black light.
Which substances appear different under the regular light? and Which substances appear different under black light?
Why do you think that certain substances glow in the presence of ultraviolet radiation and not in the presence of infrared radiation?
For this activity, you will need to work with at least one partner. Obtain three syringes, two with a 50 mL capacity and one with a 10 mL capacity. Also obtain a latex tubing that can fit tightly over the syringe opening.
Connect the tubing to the 50 mL syringes, remove the plungers from both syringes and then hold them at the same level. Have your partner pour water into the one syringe such that the water will flow through the tubing into the other syringe until both syringes are full.
Remove all the air from both syringes and the tubing. Insert the plunger into one syringe and push it all the way down. Use a plastic tub to catch the overflow of water from the syringe. . Insert the plunger into the second syringe and push it halfway down. No air should be left in the syringes or the tubing. Ensure the plungers are able to move easily inside the syringe.
Use burette clamps to mount each syringe onto a support stand. Have your partner hold one support stand steady and place a 1-kg mass on that syringe's platform. Hold the other support stand steady as you push down on that syringe’s platform until the mass on the other syringe moves.
Estimate how much force you used to move the 1kg mass and record it as the control force.
Remove the mass and disconnect the tubing from one syringe. In its place, attach the 10 mL syringe in the same way you did for the previous syringe. Fill it up with water again but this time insert the plunger in the 50-mL syringe and push it down only halfway. Then attach the plunger into the 10 mL syringe ensuring once gain that there is no air trapped inside the syringes or the tubing.
Place the 1 kg mass on the 50 mL syringe and push the plunger on the 10 mL syringe until the mass moves. Record an estimate of the force you used to push the mass. You can use relative terms here, more force than the control, less force than the control. Then remove the mass and place it on the 10 mL syringe. Push the plunger on the 50 mL syringe until the mass moves and again record an estimate of the force your needed to move the mass.
Your records will include:
Control force: amount of force used when both syringes were 50 mL.
Relative amount of force applied on the 10 mL syringe to move the mass placed on the 50 mL syringe.
Relative amount of force applied on the 50 mL syringe to move the mass placed on the 10 mL syringe.
Your teacher will provide you with three water samples in beakers. (samples may include regular tap water, well water, rain water, pond water, ground water from a livestock farm etc. Do you notice any physical and chemical differences between the samples? Record the characteristics of the water samples.
Place a filter paper cone in a funnel and place the funnel in the empty beaker. Using the graduated cylinder, pour 100 mL of one water sample through the filter paper. Wait until all the water has drained through the filter. Observe the filter paper and the water in the beaker and record your findings. How is the filtered water different from the unfiltered sample? Filter the other water samples using the same steps and record your observations. Does the filter paper work effectively for all water samples?
Testing for Chlorine
Pour a small amount from each water sample into separate test tubes. Add 5 drops of silver nitrate solution to each test tube. Record any changes you see in the water in the flasks. (note that this is one of the tests for chlorine, there are many other tests, most of them rely of a color change where the degree of color change is correlated with chroline levels. Some tests come with standard colors that you can compare your sample with to estimate the chlorine levels.)
Testing for water hardness
Measure 100 mL of each sample into 3 separate Erlenmeyer flasks. Add 1 mL of soap flakes to each flask and put the stoppers in the flasks. Shake each flask vigorously for 30 s. Observe the soap froth in each flask. Record your observations.
Testing for Living Organisms
Pour 125 mL of the tap water into a clean Erlenmeyer flask. Put the same amount of each of the other samples in separate flasks. Add 5 drops of bromothymol blue to each flask. Tightly stopper the flasks and label them. Record the colour of the solution in each flask. Incubate the flasks in a warm, dark place for 24 hours. After 24 hours, remove the flasks and record the colour of the solution in each one.
Dissolve a tablespoon of salt in a bowl of clean water. Taste the water by touching it and tasting it off your fingertip. Place the bowl inside a plastic bag and close the top of the bag tightly with a rubber band or string. Set the bag and bowl next to a sunny window, and leave it there for 24 hours. Open the bag, and touch the liquid collected on the inside of the bag. Taste it to find out if it is salty.
Write an essay in response to the question: How can we keep our water quality levels high enough to protect ourselves?
Data can be collected in several forms such as numbers, images, statements etc. Often times, this data is hard to intepret and scientists can use charts or graphs to illustrate the patterns or trends in the data. For example, pie charts are used to effectively represent data that is part of a whole. Bar graphs may be used to assess relationships between sets of data.
Researchers have conducted a survey to count the number of species on the Earth and came up with the following numbers:
Organisms | Number of Species |
---|---|
Plants | 240,000 |
Spiders and Scorpions | 50,000 |
Roundworms | 32,000 |
Flatworms | 30,000 |
Birds | 23,000 |
Protozoa | 40,000 |
Earthworms | 16,000 |
Mollusks | 62,000 |
Bacteria | 3,800 |
Insects | 220,000 |
Mammals | 3,750 |
Come up with a way to visually represent the data from the table above to clearly represent the numbers of different species reported by the scientists. You may use technology as needed.
What information about the data is easily represented by the design you selected. What other designs would be used to represent other pieces of information in the data?
Species are usually very similar in appearance and it may be difficult to identify obvious differences.
For example, work with a partner in class to measure the length of your thumb. We will use a frequency distribution table for this activity. The whole class will enter their data on the same table using tallies.
Thumb length in cm | Number of Students |
---|---|
2.9cm or Less | |
3cm - 3.9cm | |
4cm - 4.9cm | |
5cm - 5.9cm | |
6cm or more |
What shape does the graph have? What does it show about variation in thumb length among your classmates?
Predict whether the graph would have the same shape if you measured the thumb length of students in other classes or in college.
Select one of the genetic technologies you have read or heard about. Research and describe how this technology works. Describe possible applications for this technology. What potential questions or issues may arise from the use of this new technology?
Some genetic technologies include cloning, artificial insemination, in-vitro fertilization, genetic engineering etc.
Rice is a staple for millions of people in many countries. However, rice does not normally contain vitamin A. Scientists utilized genetic technologies to create a genetically engineered strain of rice that does contain vitamin A to reduce the prevalence of vitamin A deficiency. Read about the genetic technology used to create 'golden rice' and its nutritional benefits.
Until the late 1600s, scientists hypothesized that a human child was the product of only one parent. They thought that sperm held a fully formed tiny fetus that grew in size for nine months until it was large enough to be born. Around 1685, Anton van Leeuwenhoek improved the microscope, which provided evidence that no longer supported this hypothesis.
Every year, several tourists visit national parks to observe various animals across the world. Some tourists use different kinds of vehicles and drive on ill-defined paths that can compromise the vegetation and the soil compaction in national parks. Some tourists install cameras in the national parks to observe animal behavior and other characteristics causing varying levels of impacts on the national parks. Although some of these activities are aimed for research to improve the integrity of national parks, most of these toruist activities are simply for recreation. Animals may have to change their behavior to successfully live in ecosystems with increasing numbers of humans. Other human activities occuring on national parks include hunting, hotels, skiing, swimming pools, camping etc.
Research the kind of human activities occuring on national parks providing examples.
Describe how these activities affect the animals in the national parks.
Write a summary or your recommendation about what policies needs to be changed so as to reduce the impact of tourism on wildlife welfare.
Your teacher will provide you with 5 'unknown' substances. Perform the tests described below to identify the properties of the substances.
Assessing Appearance
Place a small sample of each substance on different places on a blank piece of paper, ensuring the samples of different substances are not in contact. Examine the samples with and without magnifying glasses and describe their appearance. Record your observations.
Crystal shape
Use a hand lens or microscope to observe the crystal structures. Record your observations.
Behavior in water
Use one large sheet of wax paper or a spot plate for all your samples. Place a small amount of each powder on the wax paper or spot plate. Add a drop of water to each powder. Record your observations.
Behavior in acid
Place a small amount of each powder on a new sheet of wax paper or a clean spot plate. Add a drop of 5% acetic acid solution or 5% hydrochloric acid solution to each powder and record your observations.
Behavior in Iodine
Place a small amount of each powder on a new sheet of wax paper or a clean spot plate. Add a drop of iodine solution to each powder and record your observations.
Were you able to identify all substances? Describe how you inferred what substance or substances were in your unknown sample. Were some tests more useful than others? Were the results of some of the tests confusing?
The unknown substances should include salt, baking soda, corn starch, sodium nitrate, sodium thiosulfate
Complete the table below:
Compound | Elements in the Compound | Number of atoms |
---|---|---|
CaO | ||
CaCl2 | ||
Al2O3 | ||
Na2O | ||
AlCl3 | ||
KCl | ||
NaOH |
For this activity, you will use an Erlenmeyer flask containing 75 mL of dilute hydrochloric acid and 3 drops of methyl orange indicator. This is a model of an upset stomach. Methyl orange is orange in color when it is in an acid environment and turns yellow when the environment is neutral or basic. You will need to add different antacids to the model stomach and when the color changes, the stomach is no longer upset. In this reaction, carbon dioxide gas is produced. Ultimately, you need to determine which antacid worked best and the differences in efficacy between tablets and liquid antacids.
We can design several tests to assess the factors influencing the rate of reaction. For example, we know that increasing the temperature of the reactants most frequently increases the rate of the chemical reaction. Mixing the reactants using a stirring rod can also increase the rate of reaction. What other factors can you think of?
Design an experiment that can be used to assess the impact of temperature on the rate of a chemical reaction.
In this activity, you will measure the pH of various substances using either a pH meter, chemical indicators, or pH paper. The pH meter shows the pH of the substance measured on a scale of 1-14 with lower numbers indicating acidic pH and higher numbers indicating basic pH. Of course a pH of 7 is neutral. Indicators and pH papers can be use to determine pH by color change. A color guide can be used to help you measure the pH of acids and bases.
We can alter the pH of a substance by adding an acid or a base depending on which direction we would like to change its pH. When a substance's pH is altered to become neutral, we say the substance has been neutralized.
In this activity, you will be testing for different types of organic molecules. This table shows the color changes associated with positive reactions.
Substance | Test and results |
---|---|
Glucose | Benedict’s solution turns from blue to yellow-orange-red |
Starch | Iodine solution turns from red-brown to blue-black |
Fats | Fats and oils leave a spot on brown paper that light can pass through |
Proteins | Biuret solution turns from blue to purple or mauve |
Testing for the presence of glucose
Place a small amount of the sample in a test tube. Add a small amount of water to dissolve the substance. Add 10 drops of Benedict's solution and mix. Heat the tube in warm water for 2 minutes then record your results.
Testing for the presence of starch
Place your sample in a test tube or a in a well plate. Add a drop of iodine solution and record your observations.
Testing for presence of oils/fats
Divide a piece of brown paper into sections corresponding to the number of samples to be tested. Label each section accordingly to avoid mixing them up. Place a drop of each substance in their corresponding section. Leave the setup for 5 -10 minutes then look through the paper by holding it up to the light.
Testing for presence of proteins
Place samples in a test tube or a well plate. You may need to add a small amount of water if samples are in powder form. Add 3 drops of Biuret solution into each sample and record your observations.
Testing unknown samples
Your teacher will provide you with 8 samples to test for the presence of glucose, starch and protein. Describe how you would conduct these tests and create a table to report your results.
Attach a cork to a 15 cm of thread. Hang the cork from the end of your desk by taping the opposite end of the thread to the edge. Rub an acetate rod or plastic drinking straw with some wool or fur. Slowly bring the rod close to the hanging cork. Record your observations.
Now rub the cork on the wool or fur, and then rub the acetate rod with the wool or fur. Slowly bring the rod close to the hanging cork. Record your observations.
Turn on a water tap so that only a very thin stream of water is flowing. Rub the acetate rod with the wool or fur once again, and slowly bring the rod near the stream of water. Record your observations.
Your teacher will provide you with a battery (dry cell), 5 wires and 2 light bulbs.
Using the dry cell, one bulb, and wire, make one light bulb light up.
Make two light bulbs light up so that when you unhook one bulb, the other one goes out.
Make two light bulbs light up so that when you unhook one bulb, the other one stays on.
In this activity, we will determine the circuit design of an electronic toy.
Carefully take apart the toy vehicle, noting all the parts of the electrical circuit. Draw a schematic diagram for the toy vehicle and indicate the loads, conductors, switches, and energy sources in your diagram. Share your results with your classmates and see if they agree with the schematic you have drawn.
You have been asked to design a method of monitoring the temperature inside a kiln in a pottery studio. The potter has built a kiln but needs a way of measuring the temperature inside to ensure that the pottery is fired properly. You will be testing a thermocouple, a simple device that can convert heat to electricity.
You must produce a sketch to show how you could use a thermocouple to measure the temperature inside a very hot, closed environment, such as a kiln. You must prove that your thermocouple device is capable of converting heat into electricity and that it will work at high temperatures.
Why do you think the device used to produce electricity in this activity is called a 'thermocouple'
Obtain a meter stick (ruler), an aluminum foil and two white papers. Tape or tie the two white papers on the two ends of the meter stick. Attach the aluminum foil on one paper and make a pinhole not more than 1 mm wide. Now hold the meter stick in a way to allow light from the sun to pass through the pinhole and form an image on the other white paper. This may require a few tries and moving the stick until you obtain a clear good image. Get your partner to mark the edges of the image and measure the diameter. You may repeat this two or three times and then calculate the average of the three diameters.
The diameter of the sun can be calculated as:
Where d is the diameter of the image. 100 represents the length between the two papers on the meter stick.
D represents the diameter of the sun, to be calculated and 150,000,000 is the distance between the sun and the earth.
After completing this calculation, go online and find out the actual diameter of the sun. Compare your numbers and determine the difference. Was your number bigger (or smaller) than the actual number?
You can calculate the accuracy of your calculation by calculating the percent error as:
Indicate what factors could have resulted to the error.
This activity illustrates in a two-dimensional way how the Global Positioning System uses satellite signals to determine the position of someone holding a GPS receiver. A GPS receiver may be built into a cellphone, GPS enabled watch or a GPS tracker. You will need a pencil and a geometry compass. Your teacher will provide you with an enlarged copy of a map showing the positions of three satellites in respect to the earth. Imagine that you are standing in a location somewhere on the map when you turn on your GPS receiver. Satellite 1 transmits a radio signal to the receiver in your hand and the GPS device calculates that you are 1000 km from the satellite. Using the compass, measure 1000 km on the scale provided. Next, place the compass point on the position labelled Satellite 1 and draw a circle that has a radius equal to the distance from the satellite (1000 km). Repeat this step for Satellites 2 and 3, if the distances are reported to be 300 km and 940 km respectively. The spot where all three circles meet on the map indicates your position on the ground.