A science fair project presentation, from question to conclusion

The deck, slide by slide

Every slide as it is designed in Notebook, with its text written out beside it.

1. Does Warmth Make Yeast Work Faster?

   Year 10 science fair project

   March 2026

   Maya Okonkwo, 10C · Supervised by Mr Hughes

   01Cover

   Does Warmth Make Yeast Work Faster?

   Year 10 science fair project · Maya Okonkwo, 10C · Supervised by Mr Hughes · March 2026

2. 02Agenda

   What I'll cover

   • My question
   • My prediction
   • How I tested it
   • What I found
   • What I learned
3. 03Section

   My experiment

   Five temperatures, three repeats each, one balloon per bottle.

4. 04Key numbers

   Yeast worked fastest at 35°C

   Each bottle had the same yeast, sugar and water. Only the water temperature changed between groups.

   • 15 — Bottles tested
   • 5 — Temperatures
   • 35°C — Fastest temperature
   • 0 cm — Growth at 60°C
5. 05Chart

   At 35°C the balloon grew five times more than at 15°C

   Chart: 15°C (cm), 35°C (cm) across 5 min, 10 min, 15 min, 20 min.

   • 15°C (cm): 5 min 0.6 · 10 min 1.2 · 15 min 1.9 · 20 min 2.5
   • 35°C (cm): 5 min 3.6 · 10 min 7.9 · 15 min 11 · 20 min 13.6

   After 20 minutes the 35°C balloon measured 13.6 cm, against just 2.5 cm at 15°C.

6. 06At a glance

   My project at a glance

   • Warmth helps yeast, but only up to a point — Gas production rose from 15°C to 35°C, then dropped. At 60°C nothing happened at all, because the heat killed the yeast.
   • Prediction partly right — I guessed 45°C.
   • 3 repeats each — Results within 0.6 cm.
   • 4 sources used — Book, sites, my teacher.
   • 2 weekends — To run all 15 tests.
7. 07Points

   Three things my results show

   They match what my textbook says about enzymes and temperature.

   • Yeast is a living thing, and its enzymes work faster as they warm up, so more carbon dioxide is made.
   • Above about 40°C the enzymes start to change shape and stop working, so the gas slows down.
   • At 60°C the yeast died within minutes, which is why bakers never use boiling water for dough.
8. 08Two columns

   What I kept the same, and what I changed

   Kept the same

   • 7 g of dried yeast per bottle
   • 2 teaspoons of sugar
   • 100 ml of water

   Changed

   • Water temperature, 15°C to 60°C
   • One temperature per group
   • Nothing else between bottles
9. 09Comparison

   My prediction against what actually happened

   I predicted

   • Fastest at 45°C
   • Steady growth all the way up
   • Some gas even at 60°C

   I found

   • Fastest at 35°C
   • A sharp drop above 40°C
   • No gas at all at 60°C
10. 10Table

    My results, averaged over three repeats

    Temperature	10 min (cm)	20 min (cm)	Notes
    15°C	1.2	2.5	Slow start
    25°C	3.8	7.4	Steady
    35°C	7.9	13.6	Fastest
    45°C	5.1	7.2	Slowed down

11. 11Timeline

    How my project came together

    1. JanuaryChose my question and read about yeast and enzymes.
    2. FebruaryWrote my method and did a practice test at home.
    3. Early MarchRan all 15 tests over two weekends and recorded results.
    4. Late MarchDrew my graphs and made this presentation for the fair.
12. 12Process

    How I ran each test

    1. MixYeast, sugar and water at the set temperature.
    2. SealStretched a balloon over the bottle neck.
    3. WaitKept the bottle in a water bath for 20 minutes.
    4. MeasureMeasured the balloon with string and a ruler.
13. 13Composed

    From question to answer: how my science project worked

    1. Question: Does warmth speed up yeast? (Planning)
    2. Research: Textbook, websites, my teacher (Planning)
    3. Test: 15 bottles, 5 temperatures (Experiment)
    4. Measure: Balloon size at 10 and 20 min (Experiment)
    5. Conclude: Fastest at 35°C, dead by 60°C (Planning)

    Checks

    • Every test: thermometer reading
    • Every bottle: same measuring spoon
    • Every group: three repeats

    	Source	Type	Used for
    1	GCSE Biology textbook	Book	Enzymes and heat
    2	School science website	Website	Method ideas
    3	Baking science guide	Website	Why bakers use warm water
    4	Mr Hughes	Teacher	Checking my method

    Keeping it fair

    • One variable: Only temperature changed
    • Repeats: Three bottles per temperature
    • Same timing: Measured at exactly 10 and 20 min

    Next time: Use a gas syringe for exact volumes

14. 14Image

    The balloon test, step by step

    As the yeast feeds on sugar it gives off carbon dioxide. The gas fills the balloon, so a bigger balloon means faster work.

    • Cheap and easy to repeat at home
    • Shows the result you can see

    Image: Row of plastic bottles with balloons of different sizes on a kitchen table

15. 15Team

    People who helped me

    • Maya Okonkwo, Student, Year 10. Planned and ran every test.
    • Mr Hughes, Science teacher. Checked my method.
    • Ms Lindqvist, Lab technician. Lent me thermometers.
    • Daniel Okonkwo, My brother. Timed the tests.
16. 16Quote

    Why this matters outside the lab

    “Dough rises best somewhere warm, never hot. Now I know why my grandma covers her bread dough by the oven.”

17. 17Closing

    Warmer helps yeast, up to 35°C

    Next I want to test whether the type of sugar changes the result. Thank you for listening — any questions?

Questions