Activity 5.2 Showing diffusion In this experiment you can see diffusion taking place. Your teacher will give you a dish containing a jelly called agar, which has been made using water and Universal Indicator solution. cork borer Petri dish agar stained with Universal Indicator solution Carefully cut a circle from the jelly in the centre of the dish. Use a dropper pipette to place a small amount of sodium hydroxide solution in the hole you have made. Questions A1 What is Universal Indicator solution used for? A2 What does the colour of the jelly tell you? A3 Record what happens over a period of time. You may find it useful to draw diagrams. A4 Explain what is happening in terms of particles.
Answers
Answer:
here is your answer
Explanation:
All biological cells require the transport of materials across the plasma membrane into and out of the cell. By infusing cubes of agar with a pH indicator, and then soaking the treated cubes in vinegar, you can model how diffusion occurs in cells. Then, by observing cubes of different sizes, you can discover why larger cells might need extra help to transport materials.Agar-agar powder
Digital scale
Graduated cylinder
Water
Whisk or fork
Microwaveable bowl or container at least 500ml in volume
Microwave (not shown)
Hot pad or oven mitt
Heat-safe surface
pH indicator, such as bromothymol blue or phenolphthalein
Ammonia
Small glass baking pan or cube-shaped silicone ice-cube molds
Clear plastic metric ruler
Sharp knife
Clear container for immersing agar cubes
Vinegar
Calculator
Pencil and notepaper
Spoon
White paper or plate
TimersMeasure out 1.6 g of agar-agar and 200 ml water. Mix them together with a whisk or fork in a large microwave-safe bowl.
Heat the solution in the microwave on high for 30 seconds. Remove to a heat-safe surface using a hot pad or oven mitts, stir, and return to the microwave for 30 seconds. Repeat this process until the mixture boils. (Keep your eye on it as it can boil over very easily!) When done, remove the container, and set it on a trivet or other heat-safe surface.
Choose ONE pH indictor to work with (either bromothymol blue or phenolphthalein) and add a few drops of it to the agar solution. If you’re using bromothymol blue, add enough indicator so that the mixture turns blue. If it has a greenish hue, add ammonia a drop at a time until it is blue (see photo below). If you're using phenolphthalein, add enough indicator so that the mixture turns pale pink. Add ammonia drop by drop until the mixture turns (and remains) a bright pink color (see photo below).
Carefully pour the agar solution into silicone ice-cube molds or a small glass baking pan. Make sure the agar block(s) will be at least 3 cm deep when they solidify. If you don’t have enough solution, make more using the ratio of 0.8 g agar-agar powder to 100 ml water.
Let the agar cool until it solidifies (an hour is usually sufficient). Remove the agar blocks from the molds or cut in the pan with a sharp knife to obtain two sets of cubes of three sizes: 1 x 1 x 1 cm, 2 x 2 x 2 cm, and 3 x 3 x 3 cm. If you're using bromothymol blue, you should have two sets of blue cubes. If you're using phenolphthalein, you should have two sets of pink cubes. The sets need to match in order to compare the color change later on in the Snack.
Answer:
what does the color of the jelly tell you