Complex sentence: Whilst lecturing he insisted his students had a sound knowledge of the sciences so that they could understand why engineering theories worked, he also built the first engineering laboratory in the country so that hi spupils could experience the practical side of the subject.
Split into simpler sentences: Whilst lecturing he insisted his students gain a sound knowledge of the sciences so that they could understand why engineering theories worked. He also built the first engineering laboratory in the country so that his pupils could experience the practical side of the subject.