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Difussion in Agar Cubes – Lab Report

Essay by   •  September 27, 2016  •  Lab Report  •  529 Words (3 Pages)  •  1,455 Views

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DIFUSSION IN AGAR CUBES – LAB REPORT

Research question

What is the effect of temperature change on yeast fermentation?

Background

The rates of chemical reactions may affect by temperature. The purpose of this experiment was to test the effect of different temperatures on the rate of carbon dioxide production in yeast by measuring the fermentation rate. Yeast is good for this experiment because of its characteristic of alcohol fermentation.

Yeast fermentation:

 C6H12O6---- 2CH3CH2OH + 2CO2 (+2ATP)

Hypothesis

If temperature has effect on yeast fermentation, the higher it is, the more CO2 produce will be produced. However, at some point the temperature can be too high and destroy yeast cells, causing gradually less carbon dioxide production.

Variables:

dependent:

  • the temperature, 20, 30, 40, 50, degrees Celsius

independent:

  • the rate of CO2 production

controlled:

  • amount of yeast
  • type and quantity of sugar which we add to help yeast ferment quickly:1 spoon, common sugar
  • amount of water
  • Time we start measuring
  • Volume of the solution – 5cm height in each test tube
  • The method of measuring the height of CO2 bubbles.

Controlling the variables

Type of solution

We put 1 spoon of sugar into 3 spoons of yeast and then add 3ml water.

The solution temperature

We measure it with a thermometer and control it with achieve hot water from the lab office as soon as possible. The same amount of water in each beaker is also controlled.

Time we start measuring

We measure this with a timer (± 0.5 s)

The method of measuring the length of cube edges

We use the same ruler for all

Apparatus and materials

  • Yeast
  • Sugar
  • Ruler
  • Beaker
  • thermometer
  • Timer
  • Spoon
  • Test tube
  • water

Method

This is for one of the temperature.

  1. Add 3 spoons of yeast into test tube.
  2. Then add 1 spoon of sugar.
  3. Then add 3ml water
  4. Put the tube into the beaker with 20 degrees water.
  5. Immediately turn on the timer.
  6.  Leave the tube in the solution for 1 minute.
  7. After the 1 minute had passed, take out the tube and measure the height of CO2 bubbles.
  8. Take notes.

Safety

Too much CO2 may lead the popping of the tube plug. The tube shouldn't point to people.

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