Expert: Walter Hintz - 5/18/2008

Question
I bought 2 viles of agar for a science fair project.The directions said 1/2tsp of agar to 1 cup water.I read online 1/2tsp to 1/4c.water??????? already mixed agar with the 1 cup directions.will my science work? will a heating pad help the bacteria stay warm enough to grow? do you need heat???how long for bacteria to grow//

Answer
Hi toni
The agar should work as long as it is a gel.  Follow the directions on the product not what the internet says.
Bacteria need warm temperatures and a heating pad will probably be too warm.  They grow best at body temp (98 degrees) in 24 hours You can use a light from a regular bulb.  They would take about 12 hours longer.  After 48 hours no new growth will occur.
 I have helped a lot of students with bacti projects so if you need more help let me know.

walter