Experiments

• Filtration - departing an insoluble solid and a liquid.

  1. Set up the apparatus

  2. Slowly and carefully pour the mixture into

  the filter paper as shown.

  3. Allow time for the water to separate from the soil.

  
• 1. Cut a strip of chromatography paper to fit inside the gas jar
  2. draw a horizontal line 2-3 cm from the bottom of the paper.
  3. Using the capillary tube, place a small concentrated spot of the ink/colour to be separated on the centre of the line.
  4. Pour a suitable solvent into the gas jar, ensuring that the level of the solvent is below the level of the ink.
  5. Back in the jar, place the chromatography paper, and hang it from the glass rod.Use a paper clip to ensure that the paper does not fall into the solvent.
  6. Allow time for the solvent to soak up to near the top (10-15 minutes).

  
• Onion

  Preparing the slide:

  1. Remove outer, dry scaly leaves of an onion.
  2. Use a tweezers to pull a strip of thin, translucent epidermis from the onion.
  3. Place a the epidermis on a microscope slide.
  4. Add two drops of iodine using a dropper, to stain the nucleus (dark brown).
  5. Using a mounting needle slowly add a cover slip at a 45° angle (reduce air bubbles).
  6. Note: the purpose of the cover slip is to protect the microscope lens.
  7. Examine using course focus wheel and then sharpen the image with the fine focus wheel.
  8. Results - nucleus is brown and cell walls are visible
• To investigate the effect of exercise on the pulse rate

  Hypothesis: Exercise increases heart rate.

  • The pulse is detected by placing two fingers on the wrist or neck (below jaw).

  2. In a sitting (resting) position determine your pulse rate at rest and record result. The resting pulse rate is the control.

  3. Using a stopwatch, jog on the spot for 2 minutes and immediately count your pulse rate straight after. Record result.

  4. Compare results and graph data.

  Result:
• The pulse rate increases with exercise.

  Conclusion:

  • Muscles use more oxygen (respire more) when exercising thus requiring the heart to pump oxygenated blood around the body faster.
• Co2 in inhaled and exhaled air.

  Hypothesis: There is more carbon dioxide in exhaled air compared to inhaled air.

  1.Using a graduated cylinder place 10 mL of limewater into two test tubes.

  2. Set up the apparatus (diagram).

  3. Suck in air through tube X.

  4. Blow air out through tube Y.

  5. Record which test tube turns limewater milky first.

  6. Note: Limewater turns colourless to milky in the presence of carbon dioxide.

  More co2 in exhaled air
• Diagram for co2 experiment

  
• Melting point - (candle wax).

  1. heat the substance in a test tube in a water bath.
  2. Record the Temperature every 30 secs for 5 minutes. Then observe the change of state

  
• Tes for oxygen gas

  • Place a lid under the jar filled with oxygen gas.
  • Light a splint and blow it out then place it in the jar of oxygen then it will relight
• Evaporation - to separate a soluable solid and a liquid. The solvent (water) evaporates and the solute is left behind.

  1. Set up apparatus + heat directly until most of the water has evaporated
  2. Using tongs (similar to a scissors), carefully transfer the evaporating dish onto a beaker of boiling water.
  3. Evaporate the rest of the water (solvent) and remove the salt from the dish when cooled.