A professor got a new idea from a sunburn . Sunlight changes DNA shape . Molecules can hold energy . Twisted molecules can release stored energy later . This clean technology is cheap . Her system stores more energy than phone batteries . The stored heat was strong enough to bubble water . A big problem is it needs UV light . She wants to use normal sunlight . Future versions could be clear paints on windows .

Phrases:

big problem . 大問題 . fossil fuels . 石化燃料 . heat energy . 熱能 . later on . 隨後 . small amount . 少量 . think about . 想一想 . ultraviolet light . 紫外線 .