An important part of enabling the future information infrastructure is to provide convenient services for application users that make such an environment highly functional and easy to use for the non-expert. In other words, the scientist should be able to focus on the science but should have sophisticated tools at hand that enable new and enhanced modalities in which science can be performed. We describe a general architecture that provides access to scientific applications. We demonstrate how such services can interact with each other and be reused by the scientific application architect to orchestrate Grid services. Our architecture is implemented by reusing concepts, infrastructures, and middleware from Web and Grid services, as well as from the newest Globus Toolkit and the Java CoG Kit. We apply our general architecture to a specific application: Active Thermochemical Tables. This application demonstrates a number of interesting and future-oriented uses, such as the need for batch processing, interactive and collaborative steering, use of multiple platforms,visualization through large displays, and access via a portal framework. Besides the innovative use of the Grid and Web services, we also provide a novel algorithmic contribution to scientific disciplines that use thermochemical tables. Specifically, we modified the original approach to constructing thermochemical tables to include an iterative process of refinement leading to increased accuracy. We have designed a variety of access environments including a shell, a Grid desktop, and a portal for accessing the set of services provided, which include the display of network dependencies between the reactions a chemist may be interested in and interactive querying of associated species data. Modalities that need to be supported are the protection of intellectual property, the creation of metadata and information shared with and gathered by the community, and easy access to the service by the application scientists.