Practicals Flashcards
control variables
what you keep the same
independent variable
what you are changing
dependent variable
what you measure
Test for glucose (result, control, independent, dependent variables and risks)
Benedict’s solution turns from blue to brick red
Control –> Amount of Benedict’s solution or amount of food
Independent –> The food
Dependent –> Measure if there is glucose or not
Risk: Solutions can irritate your skin.
Test for starch
Iodine turns from orange to black
test for protein
Potassium hydroxide and copper sulphate(biruet) turns from blue to purple
Test for fat
Etanol and water solution turn from colourless to white cloudy
Effect of temperature on enzymes(experiment result, variables and risks)
The experiment consisted in iodine and adding amylase solution to each circle of iodine every 30 seconds. We must have seen that the higher temperature (60-90) didn’t work because enzymes were denatured and the lower temperature (0-20) didn’t work because the enzymes didn’t have much kinetic energy and didn’t collide fast enough with the active site. Control variable = Amount of Iodine or amylase solution. Independent = The temperature of amylase solution. Dependent = ·0 seconds between each drop of amylase.
Diffusion experiment (Results, variables and risks)
Put different sizes of agar cubes (10mm, 8mm, 6mm, 4mm and 2mm) into hydrochloric acid and time it until the agar cube has compleatly turned transparent. The results are that the smaller cubes turned transparent quicker than the bigger. Control = Strength of hydrochloric acid. Independent Variable = Size of cubes Dependent variable = Time it takes to be transparent Risk is be careful with the scalpel
Osmosis Potato Experiment (Results, Variables and risks)
Put different potato masses cylinders in sucrose solution. The more concentrated solution will loose mass as the water moves from high to low concentration. In the more dilutes solution the other way around, it will increase in mass as the water moves from a high to low concentration of water.
Pondweed experiment (Results, Variables and risks)
Pondweed is placed in water, as photosynthesis is carried out oxygen is made and we can see it through bubbles. Factors that affect rate of photosynthesis: Light intensity, carbon dioxide concentration, chlorophyll in leaves and temperature. As the lamp is moved closer there is more oxygen being made (bubbles). Control variable = temperature of water. Independent variable = Distance of the lamp. Dependent variable = The rate of photosynthesis by bubbles. Risk: Water in the lamp because of electricity.
Testing leaves for starch experiment (results, variables and risks)
Kill the leaf at 100 degrees and remove color in boiling ethanol, wash with cold water and put iodine to test starch. Results should be positive for leave with light and negative with dark and no CO2. Control variable = Amount of iodine. Independent variable = Conditions of the leaf. Dependent variable = Carries photosynthesis my making starch and testing it with iodine.
INVESTIGATING EFFECT OF EXERCISE ON BREATHING
- Stationary breathing rate of participants is recorded
- Specific exercise will be performed by participants at the same intensity for a fixed period of time
- Breathing rate after exercise is recorded
- Results are compared
Result:
- During exercise, more energy is needed via respiration to allow muscle contractions to accur to facilitate movement
- So the rate of breathing will increase to allow more Oxygen transport in blood to respiring cells for movement to occur
Investigating germinating seeds
Quadrats
- Make a map and add a grid of both areas
- With an app choose 10 random coordinates
- Place the quadrat in this coordinates
- Record the % covered over total
