Theme: Earth and the environment

Project 1: Environmental radioactivity


The terrestrial environment in which we all live is constantly exposed to natural forms of radiation, arising from a variety of disparate sources including cosmic rays and radioactive substances that are naturally present in the environment. Because radiation is not detected by our five human senses, it is difficult to discern its presence in daily life. Moreover, modern society is awash in man-made sources of radiation—from medical radiation exposure to exposure in the workplace—that exert a profound impact on human life. For these reasons, it is important to acquire a conceptual understanding of the properties and intensity of the radiation surrounding us.

In this project, you will conduct experiments through which you will come to understand the essential features of gamma-ray propagation, including attenuation with travel distance and by barriers. In addition, you will take actual measurements of environmental radiation and study the conceptual basis underlying its quantification by dose.

Project 2: Quality of water in the Hirose River


Water is an essential ingredient of our daily lives, and the maintenance and improvement of water quality in rivers and lakes—our primary sources of water—are important environmental challenges. Although the quality of water in many lakes in Japan declined precipitously during Japan’s era of rapid economic growth after World War II, the situation regarding toxic substances such as lead and mercury has improved significantly since the 1967 Basic Law for Environmental Pollution Control went into effect. However, many lakes, reservoirs, inland bays, and other bodies of water in Japan continue to suffer from problems of eutrophication due to human activity—such as the disposal of household waste water, industrial waste water, and agricultural waste water—and the present state of eutrophication-related substances is in need of improvement.

In this project, you will conduct real-world analysis of phosphorus, one of the substances primarily responsible for eutrophication; in addition to learning new analytical methods, you will study the impact of phosphorus on the environment.

Project 3: Gravity on Earth


The entirety of human life takes place in the presence of Earth’s gravity. This gravity arises from the universal attractive force exerted on all bodies by Earth. If we account for the fact that Earth is not precisely spherical, we expect that the value of the gravitational acceleration g should depend on the site at which it is measured. Moreover, the actual masses we measure are influenced by other factors, including not only the centrifugal force due to Earth’s rotation but also local variations in the structure of Earth’s crust. In this project, we will take actual measurements of the gravitational acceleration g in the city of Sendai, then analyze our results to contemplate the significance of the gravitational forces we all experience.

In this project, you will use a special type of pendulum known as a Kater’s pendulum to take high-precision measurements of the gravitational acceleration in Sendai, acquiring in the process a deeper understanding of the phenomenon of gravity.