A Variation of Charles' Gas Law

Chemistry Mini-Lab


This mini-lab attempts to test a variation of an important gas law in the field of chemistry: Charles’ law. Charles’ law relates two variables of gas, volume and absolute temperature, proportionally while assuming constant temperature. However, using another constant may change the relationship between these variables. Using an alka seltzer pill can alter the nature of gas and the temperature could have an alternative effect on the circumference of the balloon. The circumference will then indicate the change in gas volume inside the balloon. Therefore, the primary impetus of this lab is to test the effect of an alka seltzer pill on Charles’ law equation. The data collected will be the temperature of the bunsen burner and the corresponding circumference of the balloon. This relationship will be graphed and compared to Charles’s gas law to observe any profound differences.

Lab safety and Instruction

Lab Safety Equipment

  • Safety Goggles- To protect the experimenter’s eyes. Secure it tightly so that it creates a suction so no chemicals can enter.
  • Lab Coat- To protect experimenters from chemical splashes on the body. Make sure to put it on correctly and tie it tightly.

Lab Safety Procedure

  • Be sure not to consume the alka seltzer pills; this consumption could potentially cause an allergic reaction or internal failure.

  • When using the bunsen burner, make sure the experimenter’s lab coats and goggles are tightly secured.

  • Before igniting a flame, make sure all long hair and papers are away from the spark and flame.

  • Make sure the bunsen burner’s gas tap is turned to the right setting in order to create the correct flame intensity.

Materials and Equipment

  • 3 Alka Seltzer pills

  • Tub of ice

  • Tripod

  • 3 Erlenmeyer Flasks

  • Bunsen burner

  • Measurement tape

  • 3 balloons of exact color and type

  • Journal

  • Pencil

  • Timer


  1. Fill all three Erlenmeyer flasks with 15 mL of water.

  2. Crush the Alka Seltzer pills and fill each balloon with a crushed pill.

  3. Carefully stretch the balloons over the mouth of the flasks while making sure the Alka seltzer doesn’t fall into the water.

  4. Turn one balloon so that the Alka Seltzer falls into the water.

  5. When the balloon is inflated, measure its circumference using the measuring tape after 1 minute.

  6. Record the circumference in a journal.

  7. Repeat Step 4 with another balloon.

  8. Put this flask on the tripod and light a bunsen burner underneath it.

  9. Repeat Step 5

  10. Repeat Step 6

  11. Repeat Step 4 with the last balloon.

  12. Put this flask in the tub of ice.

  13. Repeat Step 5

  14. Repeat Step 6

  15. Compare and analyze the change in size for the different temperatures.