Green tea and Daphnia
The hypothesis that herbal green tea reduces the heart beat of daphnia is proven to be true.
Green tea has a lot of healing properties and it contains antioxidants that can help to protect our cells from damage by the toxins in our body. However, excessive consumption of more that 5 or 6 cups of tea a day can cause insomnia, appetite loss, irregular heartbeat, diarrhea and dizziness.
The science fair project can also be done by using different types of herbs like garlic or ginger.
Try to repeat the science fair project by adjusting the room temperature.
Green herbal tea - http://theherbaldigest.com/tag/rregular-heartbeat/
Green tea side effects - http://www.greenteasecrets.com/greenteasideeffects.html
Altace - http://www.healthsquare.com/newrx/alt1014.htm
Daphnia - http://en.wikipedia.org/wiki/Daphnia