I had ESOL students when I taught third grade science. I found that using picture vocabulary cards was extremely helpful. I would also modify tests/quizzes to have two choices instead of four in a multiple choice format.

In order to help my students understand vocabulary and content I use a lot of visual aids in class and on the tests. Students have the opportunity to draw pictures for their notes. They are also provided the Spanish version of the word but are also provided the English version and must use the English version. Assessments also contain pictures and are heavily differentiated.

I have found that using thinking maps help out a lot and providing pictures with content helps as well. Also, I have few students in my classes that speak both English and Spanish fluently so I have those students work with the students who are having trouble understanding.

The suggestions I have on helping ESOL students understand is to show more visuals during my teaching. Also, have the student try the "hands on approach" to science.

Picture vocabulary cards will be your best friend in this situation. You could even take it a step further and include the language of the ESOL student on the card too. For example, if you were doing the solar system and you're teaching them about the planets, have a card with the picture of Earth, with the word Earth on one side, and for instance, if they spoke Spanish have the Spanish word for Earth on the other.

The best solution for this is using pictures and translating the words in their native language. That has worked with me. Try sending the words home ahed of time and have parents build a picture dictionary with the kid. Depending on their English Proficiency I would accommodate the assessment as well.

I would suggest using illustrations, video clips, and skits to help ESOL students understand science content/vocabulary.

I would modify science lessons to include a lot of pictures, diagrams, and labels. During ELA small group activities, you could incorporate word sorts that have science content. Repetition also helps, so referring back to vocabulary during science lessons could keep the words fresh in their minds. Try to make science fun and relevant. Include their culture in science lessons that way they may be able to make connections better.

I think what would help the most are visuals. Visuals work across language barriers. For science this could be hands on experiments, photos with labels in L1 and L2, or even a video with captions in L1.