assistant
atoms
card
caucasian
chemical
chemicals
chemist
chemistry
classroom
dutch
education
element
elements
european
experiments
instructor
labor
learn
learning
lines
male
man
middle aged
molecules
periodic table
person
pointing
points
profession
professional
research
researcher
school materials
school subject
schoolteacher
science
scientific
study
symbol
symbols
teach
teacher
teaching
wall
wall chart
wall plate
work
worker
working