Practical investigation Methods Flashcards
what is the test for starch and the positive test results
Iodine test
turns blue/ black if present
what is the test for glucose and positive test results (hint traffic light)
Benedict’s
yellow to brick red, orange, green
what is the test for lipids and positive test results
Emulsion test
if present a white emulsion will form
what is the test for protein and positive test results
Biuret test
Turns purple (lilac)
what is the investigation for photosynthesis and explain step by step
Pond weed experiment
1. you need a light source, ruler and jar to contain the water and pondweed
- place the 10cm of pondweed into the jar of water.
- cut under the stem of pondweed at a slant under water (to ensure a steady stream of oxygen)
4.once acclimatized count the number of bubbles given off by the pondweed in one minute.
- move the lamp (light source ) away by 10cm each time up to 50cm.
- Repeat the process moving the lamp each time
- repeat the experiment 3 times and calculate an average
what is the investigation the energy content in a food sample
Banana chip test
1.Fill up boiling tube with 20cm^3 of water and measure the starting temp
- Clamp tube to resort stand
- Measure the mass of the food
- Prick food with mounted needle
- light the food on fire
- place food under the boiling tube and wait until the food has completely stopped burning.
- measure the temperature of the water (final temp)
- add results to results table, empty out the water and repeat experiment with other food samples.
- To calculate use the formular
final temp - start temp (x mass of water x 4.2)/ mass of food (g)
what is the test for carbon dioxide
bubble it through lime water
turns cloudy
what is a potometer used for
to measure the rate of transpiration
describe how a student could use a potometer to measure the rate of water taken up by the plant.
- Cut shoot underwater at a slant (to avoid the risk of too many air bubbles)
- place shoot under water creating one air bubble to measure.
- measure the starting point before 1hr and the finishing point of the air bubble after the 1hr.
- calculate the distance moved of the air bubble after 1hr.
- repeat three times and calculate an average.
investigation for the population size of an organism
use quadrants
- uses several quadrants
- place them in a random position using a number generator or dice
- count how many there are- number of organisms there are in each quadrant.
- Multiply up to calculate total in large field.
Describe a practical investigation for a living organisms of osmosis
cut up a potato into identical cylinders
- get some beakers with different sugar levels
- one with pure water
- one with a very high concentration of sugar solution
then have a few other beakers with concentrations in between
- measure the initial length of the cylinders
- leave for around half-hour
- measure the final length
- if the cylinders have drawn in water via osmosis they will be a bit longer
- if they have shrunk then they have lost water via osmosis
Describe the practical investigation on how enzyme activity can be affected by the change in temp
- Add 5cm3 starch solution to a test tube and heat to a set temperature using beaker of water with a Bunsen burner
- Add a drop of Iodine to each of the wells of a spotting tile
- Use a syringe to add 2cm3 amylase to the starch solution and mix well
- Every minute, transfer a droplet of solution to a new well of iodine solution (which should turn blue-black)
-Repeat this transfer process until the iodine solution stops turning blue-black (this means the amylase has broken down all the starch)
-Record the time taken for the reaction to be completed
-Repeat the investigation for a range of temperatures (from 20°C to 60°C)
Describe the practical investigation on a non-living system in diffusion
Phenolphthalein is a pH indicator—- it’s pink in alkaline solutions and colourless in acidic solutions
- First make up some agar jelly with phenolphthalein and sodium hydroxide
- Put some hydrochloric acid in a beaker
- cubes of jelly and place in beaker
- If you leave the cubes for a while they’ll eventually turn colourless as the acid diffuses into the agar jelly and neutralises the sodium hydroxide.
- you can investigate the SA:VOL ratio by changing the size of the cube
practical investigation of breathing in human
- first sit still for five minutes.
- then for one minute count the amount of breaths you take
- now do four minutes of exercise
- as soon as you stop exercising count your breaths for one minutes
- repeat experiment three times and calculate an average.
