Boston — Susan Hendee remembers the houses: ''They were awful, just like a couple of boards. I'd never seen anything like that.'' Joe Anderson couldn't believe what the babies looked like: ''They were so skinny and bony, they made me feel like I wanted to help.''
Laurie Edmond can't forget how hard the older children studied in school: ''They were really concentrating. They knew their parents couldn't go to school, and they knew they wouldn't get another chance.''
Fran Griggs says he still feels bad when he gets ''greedy'' at home: ''I learned that there are other people in the world who barely have any food. Sometimes when I'm at home, I get greedy for more food, and then I wonder if the people in Guatemala have enough to eat. I think maybe I could send them my left-overs.''
Those are just a few of the things these seventh graders remember about some slides they saw last spring. Although it's been almost a year since a UNICEF volunteer came to their school in Chichester, N.H., to show them pictures and talk about UNICEF projects in several Latin American countries, they still recall the afternoon vividly.
''We have a very sheltered, small town here,'' says their teacher, Pat Brown. ''The kids here aren't rich, but neither do they have any concept of the level of poverty in Latin America. Mrs. Williams's talk made quite an impression.''
Mrs. Elizabeth Williams visited the Chichester Central School last year when her grandson's class invited her. A former Massachusetts state representative for the United Nations Children's Fund, she has spent more than 15 years talking to children about UNICEF. An unpaid worker, she also has financed her own trips to Guatemala, Ecuador, and India to see UNICEF projects first hand.
Mrs. Williams is one of the tens of thousands of volunteers UNICEF depends upon to turn statistics into felt needs.
To read UNICEF's recently released report, ''State of the World's Children 1981-82,'' for example, is to be overwhelmed by numbers. Some 17 million children in the world's developing countries died of malnutrition and disease in 1981, according to UNICEF estimates. And ''of the 125 million who will be born (in 1982), 17 million will again be dead before their fifth birthday,'' UNICEF reports. In some countries, one-third of the children will receive no education, and most will not complete primary school.
''. . . .Children themselves are relatively powerless. They have neither physical strength, nor economic sanction. They have no unions, and no votes,'' the UNICEF report points out. ''Usually it is the parents who are empowered to protect and provide. But if parents are deprived of that power, then the responsibility falls to the community of which the child is part. . . .We cannot allow the largest generation of children to grow up malnourished, unhealthy and uneducated in order to become the parents of another generation of malnourished, unhealthy and uneducated children.''
Established at the end of World War II, the United Nations International Children's Emergency Fund was set up to care for Europe's millions of displaced and hungry children. Although the words ''international'' and ''emergency'' were dropped in 1953, UNICEF remains the only UN agency committed solely to the needs of children in developing countries. It has no budget and cannot borrow money, and so depends entirely upon contributions to finance its programs. Three-fourths of the operating funds come from government donations ($233 million in 1980), and the rest comes from individual contributions and sales ($ 80 million in 1980). A spokesman for the Philanthropic Advisory Service of the Council of Better Business Bureaus says that UNICEF meets ''all the provisions'' of that watchdog agency's standards for use of funds.
As UNICEF volunteers like Mrs. Williams are quick to point out, the contributions come from an understanding of the world's needs and UNICEF's response. ''We don't push fund-raising when we talk to schoolchildren,'' she explains. ''We think there's a need to educate them about how the rest of the world lives first. Children helping children is really the theme of UNICEF.''
Mrs. Williams may begin a discussion with a group of sixth-graders by bringing a bucket full of water into the classroom. She'll have a number of children carry it around for a while, then ask them how they'd like to trudge to the nearest town several times a day to fill the bucket and carry it home for drinking water and for washing clothes.
Or she may ask how many in the class like rice, and then serve up several spoonfuls on a plate, explaing that that's all children in many countries have to eat for an entire day.
''It's a tricky business,'' says Sandy Thompson, another UNICEF volunteer who gives school talks. ''Our goal is to help kids see that they have it pretty good here without putting down other cultures or demeaning other people.
''I always start out by asking children what they consider important to grow up healthy - things like food and housing,'' she continues. ''In general, we try to get them to understand that things we consider basic and take for granted are unknown in many countries. All of us who are involved in this education aspect of UNICEF feel that in the long term it's the sense of caring that's crucial. And kids really care.''
After finding out that UNICEF can send a pound of pea seeds overseas for every $1. it receives, that a child-size hoe for a school garden costs only $5. 41, and that $50. will buy an elementary school science teaching kit, children usually want to know how they can help. Often, says UNICEF volunteer Mary Oleksiw, they come up with their own ideas for fund-raising projects. In Massachusetts during the past year:
* A Cub Scout troop decorated a ''haunted house'' at Halloween and charged 25 cents admission;
* An elementary school class sponsored a ''have a heart for UNICEF'' collection on Valentine's Day;
* A class of seventh graders did chores for neighbors for three months;
* A private school held a student-faculty soccer game;
* A community sponsored a craft fair.
''Remember Me,'' a UNICEF film made for the International Year of the Child, tells the stories of a number of children in developing countries, in their own words. The camera focuses on a young girl standing barefoot in a trash dump outside a large South American city: ''I collect and sort garbage,'' she says. ''I will marry at 12, and at 13 I will have a baby.'' Across the globe, a wistful youngster in India explains, ''I have to collect dung. I make it into balls and put them on the wall to dry in the sun. It is a dirty job, but still, I have to do it every day.'' His back strapped into a rope harness, a small boy in the Mideast tells the viewer: ''I work with my father and brothers on our boat. Pulling. . . .is hard, and when we walk in the water, for me, it is almost impossible. I cannot go to school, but I would like very much to be a teacher.''
At the end of the film, the narrator asks, ''What can we do to make a child smile?''